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Natural Medicines in the Clinical Management of Colds and Flu
Causes of Colds and Flu | Pathogenesis | Prevention of Colds and Flu
Treatment of Colds and Flu | Miscellaneous | The Bottom Line
References
 



The "common" cold is aptly named. It is something nearly everyone encounters. The U.S. population experiences nearly a billion colds annually. Children usually have about 6-10 colds per year. Adolescents and adults have 2-4. Adults over 60 typically have fewer than one cold per year.10762,10763

Influenza, more commonly called "the flu," is much more serious and much less common than the common cold. Each year 35-50 million people in the U.S. get the flu. Most people recover. But the flu still causes complications which lead to 100,000 hospitalizations and more than 50,000 deaths each year.10764

 
 
 
Pharmacy Technicians View How Natural Medicines Are Used for Colds and Flu
Causes of Colds and Flureturn to top 

More than 200 different viruses can cause the common cold. The rhinovirus is the most common. It's responsible for 30% to 50% of all colds. It is spread both by physical contact, like shaking hands and touching doorknobs, and through airborne transmission. Rhinovirus infections can occur throughout the year, but peak in April to May and September.10765 In autumn, rhinoviruses cause 80% of all upper respiratory infections.10766

Viruses that Cause the Common Cold10765,10766
Virus % of Cases
Rhinovirus 30 to 50
Coronavirus 10 to 15
Parainfluenza virus 5
Respiratory syncytial virus (RSV) 5
Adenovirus <5
Enterovirus <5
Unknown 20 to 30

The flu is caused by 3 types of viruses: influenza A, influenza B, and influenza C. No single type of flu virus is more common than another, but they do differ in their disease severity.

The influenza A virus is responsible for pandemics, flu outbreaks that spread worldwide. Influenza A causes severe disease and a significant number of deaths, even in young people. The H1N1 "swine flu" is a strain of the influenza A virus.10767

Get more information about Novel H1N1 Influenza A from Pharmacist's Letter/Prescriber's Letter.

The influenza B virus does not cause pandemics, but can cause severe disease in the elderly and other high-risk patients.10767

Influenza C causes mild disease with no seasonal variation.10767

The flu season typically lasts from November to March. Different vaccines are needed every year because of changes in viral proteins, especially in influenza A. Two proteins on the surface of the virus facilitate viral spread in the respiratory tract. These proteins can change. The changes produce what looks like a new virus to the immune system. Each time this happens the population doesn't have immunity to the "new" virus. This means the influenza virus reinvents itself to some degree every year or every few years. The greater the changes, the greater the risk for a pandemic.10767

Each year's flu vaccine is an educated guess by the U.S. Public Health Advisory Committee on Immunization Practices. This group predicts which viruses are likely to cause disease in the upcoming flu season. This decision is made 6-9 months in advance to allow production time for vaccines. A faulty prediction can result in a vaccine which doesn't fully protect against the season's prevalent flu strains.10767

Cold and flu viruses are usually transmitted by hand contact with secretions that contain the virus, either directly from an infected person or indirectly from environmental surfaces such as telephones and doorknobs. Subsequent rubbing of the eye or nose can lead to infection.10763,10766

Viral transmission can also occur by inhalation. Aerosols from an infected person enter the respiratory tract of a new host and begin colonization. Small-particle aerosols, which are thought to be the means of influenza and adenovirus transmission, can linger in the air for an extended period of time.10763,10766

There are a lot of myths about causes of the cold and flu. For example, some people believe becoming chilled or wet can cause a cold or flu. But this isn't necessarily true.10766 It may be the common timing of cool weather and peak flu season. Cold weather tends to keep people inside where exposure to infected individuals can occur more easily. Although some experts speculate that exposure to the elements might make nasal passages of some people more prone to infection, exposure to the virus is still the key ingredient.

Some people think smokers have more colds. Actually, cigarette smoking doesn't affect the incidence of colds and flu. But smokers do have more severe symptoms and longer duration of symptoms than nonsmokers.10763,10769

The effect of stress on the immune system is controversial. Some evidence suggests psychological stress might increase the risk of catching a cold.10771,10772 But other research suggests stress or a "weak immune system" doesn't seem to lead to infections in otherwise healthy people. When exposed to a cold virus under experimental conditions, nearly everyone becomes infected.10768

 
  Question #1
The common cold can occur at anytime throughout the year. What is the PEAK time of year for colds?
  •   Question #2
    During an influenza pandemic, which flu strain is most likely the culprit?
  •   Question #3
    Which of the following INCREASES the risk of cold virus infection in adults?
  • Pathogenesisreturn to top 

    Viruses colonize respiratory cells, triggering the release of immune system signals such as histamine, leukotrienes, interleukins, tumor necrosis factor, and other cytokines. The flu viruses cause extensive damage to the respiratory epithelium. In contrast, cold-causing rhinoviruses themselves don't cause changes to respiratory tissue. Rhinovirus symptoms may be caused by the body's own inflammatory response to the virus.10763,10766

    Colds typically begin with sore or scratchy throat, sneezing, nasal discharge, and stuffiness.10763,10766 Otitis and sinusitis can sometimes follow a cold. The flu often begins with a sudden headache, fever, myalgia, and malaise.10767 Influenza complications include viral and secondary bacterial pneumonia.10763,10766

    Symptoms of Cold and Flu10770,10771
    Symptom Common Cold Influenza
    Onset more gradual abrupt
    Headache mild, uncommon severe, common
    Fever uncommon or 0.5º C (1º F) increase common 37.7 to 40º C (100 to 104º F)
    Myalgia, arthralgia uncommon common
    Malaise mild severe
    Fatigue, weakness very mild, short duration common, lasts 2 to 3 weeks
    Cough (dry) mild to moderate common, severe
    Chest discomfort mild to moderate common, severe
    Anorexia uncommon common
    Nasal congestion common occasional
    Sneezing common occasional
    Sore throat common occasional

    Commonly Used Conventional and Natural Medicines for Colds and Influenza*
    Vaccines
    • Influenza vaccine (FluShield, Fluzone, Fluvirin, FluMist)
    Antivirals
    • Conventional Medicines
      • Amantadine (Symmetrel)
      • Oseltamivir (Tamiflu)
      • Rimantadine (Flumadine)
      • Zanamivir (Relenza)
    • Natural Medicines
    Immunomodulators
    Antihistamines
    • First generation antihistamines (chlorpheniramine, clemastine, diphenhydramine, etc)
    Decongestants
    • Naphazoline (Privine)
    • Oxymetazoline (Afrin)
    • Phenylephrine (Neo-Synephrine)
    • Propylhexedrine (Benzedrex)
    • Pseudoephedrine (Sudafed)
    • Xylometazoline (Otrivin)
    Anticholinergics
    • Ipratropium (Atrovent)
    Anti-inflammatories
    • Nonsteroidal anti-inflammatory drugs (ibuprofen, naproxen, etc)
    Miscellaneous
    • Saline nasal spray or drops
    *Note: Many natural products are tried for colds and influenza, but very few have reliable evidence that they work. Inclusion in this list does NOT imply that these products are effective for colds and influenza.

    		 
    Prevention of Colds and Flureturn to top 

    Vaccines

    The development of a vaccine against cold-causing rhinoviruses is unlikely. There are many different types of rhinovirus. Unlike the influenza virus types, these different types of cold viruses don't share enough in common, for example, proteins on the surface of the virus, to create an effective vaccine.

    Several vaccines against other cold-causing viruses including respiratory syncytial virus (RSV) and parainfluenza virus are in early clinical trials.10766 There are options already available for high-risk neonates and children up to age two such as the monoclonal antibody palivizumab (Synagis).

    There are many more options available for preventing the flu. Flu vaccines are very effective. They can prevent severe disease, hospitalization, and death. In fact, the U.S. Centers for Disease Control and Prevention encourages vaccination for EVERYONE over 6 months of age, except for those with contraindications.

    A flu shot is a "must" for people in high risk groups.10773
    • all adults age 50 and older
    • pregnant women who will be in their second or third trimester during flu season
    • residents of long-term care facilities
    • patients with chronic conditions such as lung disorders, including asthma, heart disorders, diabetes, renal dysfunction, or immunocompromised
    • children age 6 months to 18 years who are on long-term aspirin therapy
    • health care workers
    • household contacts of high-risk patients
    Most people should get flu immunizations in October and November. Patients are usually protected within 2 weeks of the shot and it lasts for about 6 months. Flu vaccines (FluShield, Fluzone, Fluvirin) are trivalent...each includes two influenza A strains and one influenza B strain.10773

    Children age 9 and under who are receiving a flu shot for the first time should receive 2 shots spaced a month a part.10767 More than one flu vaccine per year in adults provides no additional benefit.10861,10862

    A special H1N1 "swine flu" vaccine is currently being tested. It might be ready as soon as Fall 2009.16818

    Practice Pearl
    A common myth is that flu shots can cause the flu. Tell patients that flu shots DON'T cause the flu. Explain that they sometimes cause flu-like SYMPTOMS. About 5% to 10 % of people have mild side effects such as headache or low-grade fever for about a day after vaccination.

    FluMist is a new intra-NASAL vaccine. FluMist contains live attenuated flu viruses. Traditional influenza vaccines contain inactivated influenza viruses. FluMist is NOT recommended for people under age 5 and over age 49, pregnant women, or patients with chronic disease.

    Since FluMist is a live-virus vaccine, it also can't be given to immunocompromised patients. The flu SHOT may also be preferred for family members, healthcare workers, and other close contacts of immunocompromised patients.10774 This is because someone receiving a live-virus vaccine might transmit virus to an immunocompromised patient.

    Get the 2008-2009 update on who should get the influenza vaccine and when by reviewing Pharmacist's Letter/Prescriber's Letter Detail-Document #240902.

    Antivirals

    Antiviral drugs can be used as alternatives to flu immunization for patients who can't get a flu vaccine, though they must be used throughout flu season to prevent the flu. Amantadine (Symmetrel) and rimantadine (Flumadine) inhibit the growth of the influenza A. But they aren't effective against influenza B. Their use is also limited, particularly amantadine, by adverse effects such insomnia, restlessness, and anxiety.10775,10776

    Relenza (zanamivir) and Tamiflu (oseltamivir) are in a newer class of antivirals called neuraminidase inhibitors. They prevent viruses from penetrating the surfaces of healthy cells and inhibit the release of viruses from infected cells. Zanamivir and oseltamivir seem to be equally effective. The neuraminidase inhibitors seem to be better tolerated than the older antivirals. Zanamivir and oseltamivir are also effective against both influenza A and B.10775,10776

    Immunomodulators

    Many people try natural products promoted to "boost" or "support" the immune system. The thinking is that stimulating immune system activity might help the body ward off a virus. But some research suggests that a virus's innate ability to infect a host may be MORE important than the immune system function in catching a cold or flu.10768 In other words, a virus can cause illness even in the presence of a healthy, fully functioning immune system.

    Andrographis, also known as "Indian echinacea," is used to prevent both colds and flu. Andrographis is thought to have immunostimulant properties.2766 There's some preliminary evidence that suggests taking andrographis prophylactically reduces the risk of catching a cold by 50% after 2 months of continuous use.2772 But it's not known how long this benefit might last, or if it is safe for continuous, long-term use. This is promising, but too soon to recommend.

    Astragalus is a Chinese herb promoted to prevent colds and flu. There's some evidence astragalus can stimulate lymphocyte production.3713,10777 But there's no reliable clinical evidence that it's effective for cold or flu prevention.10778,10779 Advise patients not to use astragalus prophylactically for preventing cold or flu.

    Echinacea is widely used to prevent upper respiratory infections including colds and flu. In vitro research suggests that echinacea stimulates the immune system, causing macrophages to produce tumor necrosis factor, interleukin-1, and beta-interferon.6388,6389 Echinacea has been studied for prophylaxis against the common cold, but has consistently been shown to be ineffective.3281,3282,6386,6417,8228,10782,12354,13419,14419 Don't recommend echinacea for PREVENTING colds and flu.

    Practice Pearl
    Lots of patients associate natural medicines with immunostimulant effects with being healthy and disease free. But they might not be healthy for patients with an autoimmune disease such as rheumatoid arthritis or systemic lupus erythematosus (SLE). Theoretically, immunostimulants might activate autoimmune diseases processes. Advise patients with autoimmune disease to avoid taking immunostimulants.

    Garlic is often tried for preventing colds. Garlic might have immunostimulant activity and might also have antiviral activity.4769,8018 There's some evidence that taking a garlic supplement prophylactically might reduce the chance of catching a cold. According to one small study, patients taking a garlic supplement daily between November and February had one fewer cold episode than patients taking placebo.10787 This is promising, but more evidence is needed before garlic can be recommended.

    Advise patients who take garlic that it can have drug interactions and dose-related adverse effects...mainly bad breath and body odor. Watch for patients on warfarin (Coumadin) who take garlic. Garlic can increase INR and potentially increase the risk for bleeding.616,4802,4803

    Practice Pearl
    You can use Natural Medicines Comprehensive Database to quickly screen for interactions between natural medicines and conventional drugs. Go to the Natural Product/Drug Interaction Checker, type the name of any drug, natural ingredient, or multi-ingredient brand name supplement. Add in all the patient's medicines and click "Check Interactions." You'll get a nice summary of any potential interactions between natural medicines and conventional drugs.

    Panax ginseng, also known as Asian ginseng, might have immunostimulant effects. Some evidence suggests that it might protect against colds and improve response to the flu vaccine. Taking Panax ginseng 100 mg/day starting 4 weeks prior to influenza vaccination and continuing for 8 weeks after seems to reduce the risk of contracting both the cold and flu. It is thought that Panax ginseng might increase natural killer cell activity and the antibody response to vaccination.589 But it is still too soon to recommend Panax ginseng for this use.

    American ginseng might also be beneficial. Some evidence suggests that taking a specific American ginseng extract called CVT-E002 (Cold fX, Afexa Life Sciences, Canada) 200 mg twice daily over a 3-4 month period during influenza season might decrease the risk of developing symptoms of an upper respiratory tract infection such as the common cold or flu in adults aged 18-65 and older.11351,13192,14345 It might not reduce the chance of getting the first cold of a season, but might reduce the risk of getting repeat colds in a season.13192 When respiratory infections do occur, this extract seems to reduce the symptom severity and duration of symptoms.13192,14345 More evidence is needed to confirm these findings before American ginseng can be recommended for this use.

    Probiotics are gaining interest for reducing the risk of upper respiratory tract infections such as the common cold. Some research suggests that milk fortified with a specific strain of probiotic, Lactobacillus rhamnosus GG (Culturelle) seems to modestly reduce the incidence of respiratory infections in young children in day care.8565 Lactobacillus GG seems to stimulate some measures of immune function.7756,7757 Some clinical research also shows that children attending day care who drink a milk product containing a specific combination of Lactobacillus acidophilus plus Bifidobacteria animalis (HOWARU Protect, Danisco) for 6 months have a 45% lower risk of developing flu-like symptoms compared to placebo. This is promising, but still preliminary.

    Preliminary research also suggests a combination of the essential fatty acids linoleic acid and alpha-linolenic acid might reduce respiratory infections in children. These fatty acids might have a beneficial effect on immune function.10785 But this evidence is way too preliminary to recommend lactobacillus or fatty acids for preventing colds or flu.

    Many people try various vitamins and minerals to help ward off infections. Eating a healthy diet providing essential nutrients is important for overall health. But there is not much support for taking individual vitamins or minerals for cold and flu prevention.

    There is interest in vitamin E for preventing respiratory infections in the elderly. Some evidence suggests that vitamin E might increase antibody response to vaccination. But taking vitamin E supplements does not seem to lower the risk of respiratory infections in most elderly people.10788,12094

    Zinc inhibits rhinovirus replication in vitro, but there's no evidence this happens in vivo. Some evidence suggests that zinc might also increase cell-mediated immune response in elderly people. But there's also no reliable evidence that taking zinc supplements can help prevent a cold.10780,10783,10784 Zinc also does not seem to decrease the chance of getting the flu in vaccinated, institutionalized elderly patients.6563

    Some preliminary evidence suggests that a combination of zinc plus selenium might improve antibody response to the flu vaccine and possibly reduce the chance of respiratory infection in elderly patients with nutrient deficiency.6553,8921 But there's no reliable evidence that zinc and selenium help healthy patients with adequate dietary intake.

    Vitamin C has long been promoted for colds and flu and has generated lots of controversy over the years. Vitamin C might help immune function. It seems to increase T-lymphocyte activity, phagocyte function, leukocyte mobility, and possibly antibody and interferon production.1963,1965 But most evidence suggests that even in doses up to 1 gram/day, vitamin C does NOT prevent colds.1966,1967,1968,1987,3042,6458,7101,9832 Likewise, increasing DIETARY vitamin C intake does not seem to affect the risk of getting a cold.10780

    Practice Pearl
    Tell patients that a good way to prevent getting a cold doesn't involve taking any drug or supplement. Hand washing is one of the best ways to prevent the spread of cold viruses. Alcohol-based hand gels (Purell) seem to be more effective than water for hand washing...because it takes less time than a 1-2 minute soap and water scrub. There's some evidence that alcohol-based hand gels, which contain 62% ethyl alcohol, lower the amount of cold-causing viruses on fingers better than water alone.10863,10865 Alcohol hand sanitizers are also a good option when hand washing is inconvenient.

    A lot of people are hearing about a product called Airborne. Promotional material says that it was "developed by a school teacher who was sick of catching colds in class." But there is nothing much different about this product and many others promoted for preventing colds. It contains vitamin C, vitamin E, vitamin A, zinc, echinacea, and other ingredients. But there is no proof it can prevent or treat a cold. Don't recommend it.

    		 
      Question #4
    Which of the following is NOT recommended for those over age 49?
  • View brands containing:
    -Andrographis
    -Astragalus
    -Echinacea
    -Garlic
      Question #5
    Which of the following best describes the potential interaction between garlic and the contraceptive drug Loestrin (ethinyl estradiol/norethindrone)? HINT: See the interactions section of the garlic monograph or try the Natural Product/Drug Interaction Checker.
  • View brands containing:
    -Panax ginseng
    -American ginseng
    -Lactobacillus GG
    -Linoleic acid
    -Alpha-linolenic acid
    View brands containing:
    -Vitamin E
    -Zinc
    -Selenium
    -Vitamin C
      Question #6
    Which of the following might help PREVENT getting a cold when taken prophylactically?
  • Treatment of Colds and Flureturn to top 

    Many of the same drugs and natural medicines used for PREVENTING the cold or flu are also tried for TREATING the cold or flu.

    Antivirals

    Treatment of the common cold with antivirals has not been successful. On the other hand, treatment of the flu with antiviral drugs is well established. Amantadine and rimantadine are used to treat influenza A, but viral resistance can develop in about 25% to 35% of patients. The newer neuraminidase inhibitors...oseltamivir and zanamivir...are effective for both influenza A and B. When treatment with neuraminidase inhibitors is started within 48 hours of the onset of symptoms, the duration of the flu is cut by 1 to 2 days.10766 Neuraminidase inhibitors also decrease the risk of flu complications such as pneumonia and otitis media.10776,10791 Significant viral resistance has not been reported for these newer antivirals.10775

    Practice Pearl
    Remind patients that colds and influenza are caused by viruses. Antibiotics are effective only against bacteria. There is no evidence that antibiotics shorten the duration or lessen the symptoms of a cold or flu.

    Immunomodulators

    Many of the same "immune system stimulators" used for preventing the common cold and flu are also used for treating these infections.

    Andrographis seems to significantly improve symptoms of the common cold when started within 72 hours of symptom onset. Some symptoms seem to improve after 2 days of treatment, but it typically takes 4-5 days before maximal symptom relief.2744,2773,2774,5784,10795,12380

    Most studies have used a specific commercial product called Kan Jang, which contains an andrographis extract plus Siberian ginseng. The andrographis extract is standardized to contain 4 to 5.6 mg/tablet of the active constituent andrographolide. It's not known if other preparations are effective. If patients try andrographis, recommend Kan Jang or similar products.

    Echinacea seems to have immunostimulant and anti-inflammatory effects that might help reduce cold symptoms.10797,10798,10799 But there is controversy about how well echinacea might work for treating colds due to conflicting evidence.

    Taking some echinacea preparations seems to modestly reduce symptom severity and duration, possibly by about 10% to 30%.1412,3281,6384,6385,6392,6417,10782,10802,12355,13422,14419 But some studies show no benefit.3282,10800,11970,13419,14419

    The different findings probably relate to different study methodologies. Echinacea studies have used different echinacea species and a wide variety of preparation methods. Studies have also used different patient populations and study designs. Due to these discrepancies among studies, it's not surprising that different studies have different results.

    Echinacea preparations used in studies include a variety of extracts of the herbs and root parts of Echinacea purpurea, Echinacea pallida, and Echinacea angustifolia species.1412,3280,3281,6417,8226 Echinacea teas and fixed combination herbal preparations containing echinacea have also been used.3281,6384,6392

    As a whole, the best evidence appears to be for preparations of the Echinacea purpurea species.14419 If a patient decides to try echinacea, suggest preparations using this species.

    Practice Pearl
    Tell patients with ragweed allergies NOT to use echinacea. Echinacea is in the same plant family as ragweed and might have cross-allergenicity.

    Elderberry might be useful for treating the flu. Elderberry has both antiviral and immunomodulating effects. Elderberry seems to increase production of inflammatory cytokines, such as interleukins and tumor necrosis factor. It also seems to prevent viral attachment to cells, similar to the neuraminidase inhibitors. Elderberry is active against both influenza A and B.10796 New research shows that an elderberry fruit extract also has in vitro activity against H1N1 "swine" flu.17023

    A standardized elderberry fruit extract in a syrup formulation (Sambucol, Nature's Way) seems to shorten the duration of symptoms by about 56% and reduce the severity of symptoms such as fever and myalgia when 4 tablespoons are taken daily for 3 days.5260,12235 There is also some preliminary clinical research showing that a lozenge formulation of elderberry extract (ViraBLOC, Herbal Science) 175 mg four times daily reduces symptoms after two days of treatment compared to placebo.17022

    While the evidence for elderberry is promising, there's better evidence for antiviral drugs for treating the flu. Tell patients not to rely on elderberry for treating seasonal flu or H1N1 flu.

    Patients are likely to ask about a product called Oscillococcinum for preventing and treating the flu. Oscillococcinum is a homeopathic dilution of duck liver and heart extract.

    Homeopathy is a system of medicine established in the 19th century by a German physician named Samuel Hahnemann. Its basic principles are that "like treats like" and "potentiation through dilution." For example, in homeopathy, influenza would be treated with an extreme dilution of a substance that normally causes influenza when taken in high doses.

    The rationale behind Oscillococcinum is nonsensical, even based on homeopathic principles, based on our current understanding of the cause of the flu. A French physician discovered a substance that he called "oscillococci" while investigating the Spanish flu in 1917. He mistakenly thought that his "oscillococci" were the cause of the flu.12011

    Because these oscillococci are found in tissue from duck liver and heart, extracts of this tissue have been used to generate the Oscillococcinum homeopathic preparation for treating the flu.

    Practitioners of homeopathy believe that more diluted preparations are more potent. Many homeopathic preparations are so diluted that they contain little or no active ingredient. Therefore, most homeopathic products are not expected to have any pharmacological effects, drug interactions, or other harmful effects. Any beneficial effects are controversial and cannot be explained by current scientific methods.

    Dilutions of 1 to 10 are designated by an "X." So, a 1X dilution = 1:10; 3X = 1:1000; 6X = 1:1,000,000. Dilutions of 1 to 100 are designated by a "C." A 1C dilution = 1:100; 3C = 1:1,000,000. Dilutions of 24X or 12C or more contain zero molecules of the original active ingredient. Oscillococcinum is usually diluted from 9C to 200C and therefore usually contains no measurable active ingredient.12011

    Not surprisingly, there's no proof that Oscillococcinum prevents or treats influenza. Some researchers might claim it reduces duration, but analysis of the data shows only an insignificant one-fourth of a day reduction.10804 Advise patients not to waste their money.

    Vitamin C is commonly tried for treating colds. But there are no solid answers about how effective vitamin C is for reducing symptoms or duration. Most of evidence suggests that taking high doses of vitamin C orally might decrease the duration of cold symptoms by 1-1.5 days in some patients.1966,1967,1968,1987,6458,7102,9832 But some studies have found no effect with doses up to 3 grams daily.9833

    Some research suggests vitamin C may be more effective for treating cold symptoms in children than in adults. There may also be a dose-dependent response; doses of at least 2 grams per day seem to work better than 1 gram doses.9834

    Tell patients that the high doses used for treating the common cold, 1-3 grams daily, can increase the risk of side effects. Some patients might not think the modest benefit is worth the risk.

    Research is divided on zinc for treating colds. A lot of research suggests that zinc lozenges providing 9-24 mg elemental zinc per dose started within 24-48 hours of the onset of cold symptoms reduces the severity and duration of colds.333,334,335,337,6703,6705 But other research shows no effect.338,339,6521,6522,6700 Tell patients who want to try zinc lozenges that they'll need to take a zinc lozenge every 2-3 hours while awake. Explain that zinc can produce a dry or astringent feeling in the mouth.10864

    There is also conflicting evidence on zinc nasal sprays such as Zicam Cold Remedy Nasal Gel.6471,8628,8629,10247 There is concern about side effects related to zinc nasal sprays. Case reports and animal research has linked intranasal zinc to permanent anosmia (loss of sense of smell) in rare instances.11155,11156,11703,11704,11705,11706,11707 In 2009, Zicam nasal sprays were removed from the market in the U.S. due to over 130 reports of loss of smell. Advise patients not to use these products.

    Lots of other natural products are tried for treating a cold or flu...goldenseal, pau d'arco, astragalus, larch arabinogalactan, bee propolis, boneset, wild indigo, and Siberian ginseng. These products are often marketed as "immune system supporters." They are used alone or in combination with other natural products, such as echinacea. But there's no reliable clinical evidence that they relieve cold symptoms.

    		 
    View brands containing:
    -Andrographis
    -Siberian ginseng
    -Echinacea
      Question #7
    Which of the following statements is TRUE?
  • View brands containing:
    -Elderberry
    -Oscillococcinum
      Question #8
    Which of the following is TRUE regarding Oscillococcinum?
  •   Question #9
    A patient asks you about natural products for his cold symptoms. He says he's "allergic to everything," including dust, ragweed, and cats. Which of the following should you tell the patient to avoid?
  • View brands containing:
    -Vitamin C
    -Zinc
    View brands containing:
    -Goldenseal
    -Pau d'arco
    -Astragalus
    -Larch arabinogalactan
    -Bee propolis
    -Boneset
    -Wild indigo
    -Siberian ginseng
    Miscellaneousreturn to top 

    Saline nasal sprays or drops are sometimes recommended as a benign cold treatment. But most studies using nasal irrigation are in patients with allergic rhinitis, sinusitis, or nasal surgery.11108 Saline 2% doesn't seem to improve nasal symptoms in cold sufferers any better than normal saline (sodium chloride 0.9%).11109 There are no studies showing saline nasal irrigation lessens the severity or shortens the duration of cold symptoms. Tell patients saline sprays don't seem to help cold symptoms.

    Teas are often promoted for cold and flu symptoms. Elderflower, rose hips, goldenseal, chamomile, peppermint, slippery elm, ginger, Mormon tea, linden flowers, meadowsweet, and other herbs are used. The hot liquid may be soothing, but there's no reliable evidence for efficacy. In fact, research suggests hot humidified air doesn't affect cold symptoms.10805

    The origin of the myth, "feed a cold, starve a fever" is unknown. Some research suggests chicken soup might have a mild anti-inflammatory effect.10806 But there are no clinical studies supporting the use of specific kinds or quantities of food to treat colds or fever. Various ethanol-containing concoctions are proposed for treating colds and flu. Epidemiological research suggests that light to moderate consumption of wine, particularly red wine, can prevent colds.10807 But clinical research suggests that acute ingestion of moderate amounts of red wine, red grape juice, or ethanol doesn't have any effect on immune function.10808 Tell patients dietary interventions might provide psychological comfort, but they don't seem to affect cold and flu symptoms.

    		 
      Question #10
    A patient is interested in an zinc nasal spray for treating symptoms of the common cold. What side effect should the patient be advised about?
  • View brands containing:
    -Elderflower
    -Rose hips
    -Goldenseal
    -Chamomile
    -Peppermint
    -Slippery elm
    -Ginger
    -Mormon tea
    -Linden flowers
    -Meadowsweet
    The Bottom Linereturn to top 

    Conventional medicine doesn't have a lot to offer for cold prevention. Despite their popular use for cold and flu prevention, echinacea, vitamin C, and zinc don't prevent colds. Some evidence suggests Panax ginseng might improve response to influenza immunization.

    Treatment of cold and flu is a huge market for both conventional treatments and natural medicines. Andrographis seems to reduce the duration and severity of cold symptoms. Echinacea also seems to reduce the duration and severity of cold symptoms, but evidence has been contradictory.

    Elderberry seems to lessen the severity of flu symptoms, but there's still better evidence for conventional medicines when it comes to treating the flu.

    Vitamin C is controversial. High doses of vitamin C might reduce the duration of cold symptoms by less than a day. This might not be clinically significant for some patients. Zinc lozenges or nasal spray might reduce the severity and duration of colds if begun within 24-48 hours of symptom onset. But evidence is contradictory. And there is concern that zinc nasal spray can cause long-term or permanent anosmia.

    Avoiding illness in the first place is much better than the best cold and flu treatments available. Remind patients about simple cold prevention tactics. Avoid people with colds as much as possible. Wash hands frequently, especially when around infected patients or in public places. Avoid touching the eyes or nose to prevent self-inoculation of cold viruses.

    Encourage flu vaccination. For patients who don't like shots, the intranasal flu vaccine is a possibility for some people.

    Print a Natural Medicines Comprehensive Database recommendation chart as a reference for your practice site.

    		 
      
     
    Recommendation Chart for Natural Medicines Used for Colds and Influenza Prevention *
    Safety/EffectiveLikely
    Safe    		Possibly
    Safe    		Insufficient
    Evidence    		Possibly
    Unsafe    		Likely
    Unsafe    		Unsafe
    Effective      
    Likely
    Effective    		      
    Possibly
    Effective    		 
    -American ginseng
         		    
    Insufficient
    Evidence
    -Alpha-linolenic acid
    -Garlic
    -Lactobacillus GG
     
    -Andrographis
    -Astragalus
    -Linoleic acid
    (from flaxseed oil)
    -Panax ginseng
         		    
    Possibly
    Ineffective
    -Echinacea
    -Vitamin C
    -Vitamin E
    -Zinc
         		     
    Likely
    Ineffective    		      
    Ineffective      
     
    Recommendation Chart for Natural Medicines Used for Colds and Influenza Treatment *
    Safety/EffectiveLikely
    Safe    		Possibly
    Safe    		Insufficient
    Evidence    		Possibly
    Unsafe    		Likely
    Unsafe    		Unsafe
    Effective      
    Likely
    Effective    		      
    Possibly
    Effective
    -Andrographis
    -Echinacea
    -Vitamin C
    -Zinc
    (lozenges)
     
    -Elderberry
         		 
    -Zinc
    (nasal spray)
         		  
    Insufficient
    Evidence    		 
    -Astragalus
    -Goldenseal
    -Larch arabinogalactan
    -Oscillococcinum
    -Siberian ginseng
     
    -Bee propolis
     
    -Boneset
    -Pau d’arco
         		 
    -Wild indigo
     
    Possibly
    Ineffective    		      
    Likely
    Ineffective    		      
    Ineffective      
     KEY:
     Consider recommending this product.
     Don't recommend using this product.
     Recommend against using this product.

    * These proposed recommendations are based solely on the Safety and Effectiveness Ratings contained in Natural Medicines Comprehensive Database. This assumes use of high-quality, uncontaminated products and the use of typical doses. Keep in mind that some products are never appropriate for some patients due to concomitant disease states, potential drug interactions, or other clinical factors. Use your clinical judgment before recommending any product.

    References return to top
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    10863Widmer AF. Replace hand washing with use of a waterless alcohol hand rub? Clin Infect Dis 2000;31:136-43.
    10864Eby GA. Elimination of efficacy by additives in zinc acetate lozenges for common colds. Clin Infect Dis 2001;32:1520.
    10865Sattar SA, Abebe M, Bueti AJ, et al. Activity of an alcohol-based hand gel against human adeno-, rhino-, and rotaviruses using the fingerpad method. Infect Control Hosp Epidemiol 2000;21:516-9.
    11108Papsin B, McTavish A. Saline nasal irrigation: Its role as an adjunct treatment. Can Fam Physician 2003;49:168-73.
    11109Adam P, Stiffman M, Blake RL Jr. A clinical trial of hypertonic saline nasal spray in subjects with the common cold or rhinosinusitis. Arch Fam Med 1998;7:39-43.
    11155Jafek BW, Linschoten M, Murrow BW. Zicam Induced Anosmia. American Rhinologic Society 49th Annual Fall Scientific Meeting abstract. Orlando, Florida. September 20, 2003. http://app.american-rhinologic.org/programs/2003ARSFallProgram071503.pdf (Accessed 24 November 2003).
    11156Uebayashi H, Hatanaka T, Kanemura F, Tonosaki K. Acute anosmia in the mouse: behavioral discrimination among the four basic taste substances. Physiol Behav 2001;72:291-6.
    11351McElhaney JE, Gravenstein S, Cole SK, et al. A Placebo-Controlled Trial of a Proprietary Extract of North American Ginseng (CVT-E002) to Prevent Acute Respiratory Illness in Institutionalized Older Adults. J Am Geriatr Soc 2004;52:13-9.
    11703McBride K, Slotnick B, Margolis FL. Does intranasal application of zinc sulfate produce anosmia in the mouse? An olfactometric and anatomical study. Chem Senses 2003;28:659-70.
    11704Burd GD. Morphological study of the effects of intranasal zinc sulfate irrigation on the mouse olfactory epithelium and olfactory bulb. Microsc Res Tech 1993;24:195-213.
    11705Ducray A, Bondier JR, Michel G, et al. Recovery following peripheral destruction of olfactory neurons in young and adult mice. Eur J Neurosci 2002;15:1907-17.
    11706Mayer AD, Rosenblatt JS. Peripheral olfactory deafferentation of the primary olfactory system in rats using ZnSO4 nasal spray with special reference to maternal behavior. Physiol Behav 1993;53:587-92.
    11707DeCook CA, Hirsch AR. Anosmia due to inhalational zinc: a case report (abstract). Chem Senses 2000;25:659.
    11970Yale SH, Liu K. Echinacea purpurea therapy for the treatment of the common cold: a randomized, double-blind, placebo-controlled clinical trial. Arch Intern Med 2004;164:1237-41.
    12011Neinhuys JW. The True Story of Oscillococcinum. HomeoWatch 2003. http://www.homeowatch.org/history/oscillo.html (Accessed 21 April 2004).
    12094Meydani SN, Leka LS, Fine BC, et al. Vitamin E and respiratory tract infections in elderly nursing home residents. JAMA 2004;292:828-36.
    12235Zakay-Rones Z, Thom E, Wollan T, Wadstein J. Randomized study of the efficacy and safety of oral elderberry extract in the treatment of influenza A and B virus infections. J Int Med Res 2004;32:132-40.
    12354Sperber SJ, Shah LP, Gilbert RD, et al. Echinacea purpurea for prevention of experimental rhinovirus colds. Clin Infect Dis 2004;38:1367-71.
    12355Goel V, Lovlin R, Barton R, et al. Efficacy of a standardized echinacea preparation (Echinilin) for the treatment of the common cold: a randomized, double-blind, placebo-controlled trial. J Clin Pharm Ther 2004;29:75-83.
    12380Poolsup N, Suthisisang C, Prathanturarug S, et al. Andrographis paniculata in the symptomatic treatment of uncomplicated upper respiratory tract infection: systematic review of randomized controlled trials. J Clin Pharm Ther 2004;29:37-45.
    13192Predy GN, Goel V, Lovlin R, et al. Efficacy of an extract of North American ginseng containing poly-furanosyl-pyranosyl-saccharides for preventing upper respiratory tract infections: a randomized controlled trial. CMAJ 2005;173:1043-8.
    13419Turner RB, Bauer R, Woelkart K, et al. An evaluation of Echinacea angustifolia in experimental rhinovirus infections. N Engl J Med 2005;353:341-8.
    13422Caruso TJ, Gwaltney JM Jr. Treatment of the common cold with echinacea: a structured review. Clin Infect Dis 2005;40:807-10.
    14345McElhaney JE, Goel V, Toane B, et al. Efficacy of COLD-fX in the prevention of respiratory symptoms in community-dwelling adults: a randomized, double-blinded, placebo controlled trial. J Altern Complement Med 2006;12:153-7.
    14419Linde K, Barrett B, Wolkart K, et al. Echinacea for preventing and treating the common cold. Cochrane Database Syst Rev 2006;(1):CD000530.
    16818H1N1 (swine) flu. Pharmacist's Letter / Prescriber's Letter 2009;25:250602.
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