Docosanol

Docosanol, also known as behenyl alcohol, is a saturated fatty alcohol used traditionally as an emollient, emulsifier, and thickener in cosmetics,^[3][4][5] and nutritional supplement (as an individual entity and also as a constituent of policosanol).

More recently, docosanol has been approved by the Food and Drug Administration (FDA) as a pharmaceutical antiviral agent^[6] for reducing the duration of cold sores caused by the herpes simplex virus in the OTC medication Abreva.

Mechanism and history of antiviral drug usage

Docosanol is thought to act by inhibiting the fusion of the human host cell with the viral envelope of the herpes virus, thus preventing its replication. This mechanism has not been demonstrated empirically.^{[citation needed]}

The drug was licensed as an oral herpes medicine after clinical trials by the FDA in July 2000.^[8] It was shown to shorten the healing by 17.5 hours on average (95% confidence interval: 2 to 22 hours) in a placebo-controlled trial.^[9] Another trial showed no effect when treating the infected backs of guinea pigs.^[10]

Marketed by Avanir Pharmaceuticals, Abreva was the first but not the only over-the-counter antiviral drug approved for sale in theUnited States and Canada. In Europe, it is marketed by Healthcare Brands under the name Erazaban. In the UK it is known by the name "Blistex Cold Sore Cream". In March 2007 it was the subject of a US nationwide class-action suit against Avanir and GlaxoSmithKline as the claim that it cut recovery times in half was found to have been misleading in a California court, but the case was eventually settled and the "cuts healing time in half" claim had not been used in product advertising for some years.

Side effects

One of the most common side effects that has been reported from docosanol is headache. Headaches caused by the drug tend to be mild and can occur in any region of the head. The intensity of the pain can, in some cases, interfere with the ability of remaining focused when working or when at school.^[12]

Skin irritation may also occur at the site of application. Usually, skin irritation is mild to moderate and does not need any further treatment. It may also diminish after prolonged use of docosanol.

The most serious side effects, although rare, are allergic reactions. Some of the patients experienced the symptoms of allergic reactions, including difficulty breathing, confusion, facial swelling, fainting, dizziness, hives or chest pain.^[12] Allergic reactions are medical emergencies and individuals who experience them are recommended to seek immediate medical care in order to prevent further complications.

Other side effects may include: acne, burning, dryness, itching, rash, redness, acute diarrhea, soreness, swelling.^[13]

Contraindications

People who are allergic to one of the ingredients of Abreva are advised to avoid taking this medication. Also, it is not to be used by individuals who suffer from different medical conditions before consulting their health care provider. Interactions with docosanol may occur.

This topical has not been yet tested if it is safe to be used by pregnant women. Also, people who are taking other over-the-counter drugs, supplements or herbal preparations are recommended to consult their doctor prior to starting therapy. Nursing mothers are advised to avoid using this topical as it is not established if the active ingredients in the medicine pass into the breast milk. People who are allergic to docosanol or any other ingredient of the product are strongly advised not to use it.

Cosmetic products are recommended to be avoided while using docosanol mainly because they are likely to spread the unhealed infection and not because they interact with the topical. Lipstick is not contraindicated but it is recommended to be applied by using a different applicator to prevent spreading of the infection and recurrence. Cosmetics must be removed before applying the ointment. Also, it is important to know that herpes is highly contagious during outbreaks and patients are advised to avoid physical contact with other people as well as sharing the medicine.

Docosanol has not been specifically approved for treatment of children under 12^[13] but is not expected to produce different side effects or problems than it does in adults. This topical is only intended for external, oral-facial use and should not be administered with the purpose of curing genital herpes or shingles.