Colds and flu

Updated 07 July 2014

Treating flu

General supportive treatment is mostly applied; alternatively there are two classes of drugs currently available for the treatment and prevention of influenza infections, the adamantanes and the neuraminidase inhibitors.

Antivirals

There are two classes of drugs currently available for the treatment and prevention of influenza infections, the adamantanes and the neuraminidase inhibitors.

The adamantanes – amantadine (Symmetrel®) and rimantadine (Flumadine®) – are for the treatment and prevention of influenza A virus infections only. However, they are no longer recommended as influenza A viruses have become resistant to them.

There are two neuraminidase inhibitors, oseltamivir (Tamiflu®) and zanamivir (Relenza®) currently available for the treatment and prevention of influenza A and B infections. Resistance to either of the neuraminidase inhibitors, but usually not both, have been detected in certain influenza strains.

Prevention of flu infection with antivirals should never be a substitute for vaccination, and should be reserved for people who cannot be vaccinated or are severely immunosuppressed.

Oseltamivir is an oral medication that has been approved by the American Food and Drug Administration (FDA) for the treatment of flu in people who are one year and older and who have not been sick for more than 48 hours. It has also been approved for the prevention of flu in people who are one year and older.

For adults and adolescents the dosage is one 75 mg capsule twice a day for five days for treatment, and one capsule a day for 10 days for prevention. Oseltamivir is also available in a suspension for children.

It’s important to take the full course of prescribed medication. The most common side effects are nausea and vomiting, so rather take the medication with food. Several studies have shown that if oseltamivir is taken within 48 hours of symptom onset, the duration of illness is shortened by one to one and a half days.

Zanamivir has been approved by the FDA for the treatment of flu in people who are seven years or older and who have not been sick for more than 48 hours, and for the prevention of influenza in people who are five years and older.

Due to the risk of severe bronchospasm, it should not be used for either treatment or prevention of influenza in people with an underlying airways disease, such as asthma and chronic obstructive pulmonary disease.

Zanamivir is available as a powder for inhalation and the recommended treatment dosage is two inhalations (10 mg) twice a day for five days. The recommended dosage for prevention is two inhalations once a day for 10 days.

If you have a history of allergic reactions to milk proteins such as lactose, you should not use zanamivir, as lactose powder is used as a carrier powder.

Studies have shown that if zanamivir is taken within 48 hours of symptom onset, the duration of illness is shortened by about a day.

General supportive treatment

When you have flu, it is important to stay in bed, rest and drink enough fluids to give your body time to fight the infection.
Over-the-counter medication may help relieve the symptoms, but will not fight the virus itself. Paracetamol, aspirin or ibuprofen may help to relieve fever, muscle aches and headache, while decongestants may help to treat nasal congestion.

Please bear in mind that the use of nasal decongestants for more than five consecutive days will worsen symptoms after discontinuation due to a rebound effect.

Suppressive cough mixtures may help clear up the dry cough, typical of flu. Pregnant women should be cautious about taking drugs and children under 16 should not receive aspirin. Influenza should never be treated with antibiotics, as it is caused by a virus and not a bacterium. Antibiotics should only be prescribed by a doctor when secondary bacterial infection is suspected.

Several vitamin supplements and natural/botanical remedies have been advocated to help with the treatment of colds and influenza, but there is scanty (if any) and conflicting scientific evidence regarding the use of these preparations. A meta-analysis of seven double-blind, randomised controlled trials evaluating the efficacy of vitamin C for the treatment of the common cold, found no statistically significant benefit in duration or severity of symptoms. There are conflicting results regarding the benefit of zinc lozenges in the treatment of common cold symptoms, with most studies showing from zero to a slight reduction in the duration of symptoms.

It is important to remember that high doses of vitamin C and zinc, which is commonly used in trials, may cause gastrointestinal side effects such as stomach pain, nausea and vomiting.

The majority of clinical trials that showed that high doses of vitamin A is beneficial in the treatment of viral respiratory tract infections have been conducted in underweight, malnourished, vitamin A-deficient children. No consistent benefit has been observed in healthy children or adults with viral respiratory-tract infections.

There is conflicting evidence regarding the use of Echinacea in the treatment of colds and flu. The results of the different trials cannot be compared as the products used contain different species of Echinacea, different parts of the plant and different preparations.
It is also important to remember that Echinacea should not be given to pregnant women, children, and people taking immunosuppressant or liver-toxic drugs. The long-term safety of Echinacea also remains unknown. The benefit of other natural remedies, including elderberry, andrographis, garlic and peppermint remain unknown.

(Reviewed by Dr Jane Yeats, Department of Virology, University of Cape Town 2006)

(Updated and reviewed by Dr Jean Maritz and Dr Leana Maree, medical virologists, Tygerberg Hospital and University of Stellenbosch 2010)

 

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Flu expert

Dr Heidi van Deventer completed her MBChB (Bachelor of Medicine and Bachelor of Surgery) degree in 2004 at the University of Stellenbosch.
She has additional training in ACLS (Advanced Cardiac Life Support) and PALS (Paediatric Advanced Life Support) as well as biostatistics and epidemiology.

Dr Van Deventer is currently working as a researcher at the Desmond Tutu Tuberculosis Centre at the University of Stellenbosch.

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