Pharmacology
Under conditions reflecting normal clinical use of ABREVA (docosanol cream 10%), the active ingredient could not be quantified (LOQ=10 ng/mL) in the plasma of treated patients. Ten women with active oral-facial herpes simplex lesions were treated with ABREVA, applied as a single dose (Day 1), and as multiple topical doses (five times daily, Days 2 and 3). Blood samples were withdrawn up to 24 hours after treatment and analyzed for docosanol. Of the 209 plasma samples analyzed, the docosanol level was below the limit of quantitation in 208 and exactly 10 ng/mL in the other.
n-Docosanoic acid, the major metabolite of docosanol, is an endogenous component of cell membranes in man, particularly in erythrocytes, brain, nerve myelin sheath, lung and kidney.
The predominant mechanism for the anti-HSV activity of docosanol appears to be inhibition of fusion between the plasma membrane and the HSV envelope and, as a result, the blocking of entry and subsequent viral replication. This is in contrast to the mode of action of currently available antiviral agents. This mechanism of action explains the effectiveness of docosanol against all tested lipid-enveloped viruses that employ fusion as the sole or major means of entry into the cell and contrasts its mode of action to other antiviral agents that target a single viral protein.
Indications
ABREVA (docosanol cream 10%) is indicated for the treatment of acute episodes of recurrent oral-facial herpes simplex (fever blisters or cold sores) in adults.
Precautions
It is not known whether docosanol is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when ABREVA is administered to a nursing woman.
The safety and effectiveness has not been established. ABREVA is not recommended for children under 12 years of age.
No evidence of impaired fertility or harm to the fetus due to docosanol administered in oral doses of 10, 500, 1000, or 2000 mg/kg/day was observed in reproduction studies performed in rat and rabbits. Based on the lack of absorption of topically applied docosanol, these tested doses are a thousand-fold higher than the human dose. There are no adequate and well-controlled studies in pregnant women. ABREVA should be used during pregnancy only if clearly needed once the benefits and risk have been considered.
Supplied
Each g of cream contains: docosanol 100 mg (10%) in a cream base. Nonmedicinal ingredients: benzyl alcohol, light mineral oil, propylene glycol, purified water and sucrose stearate (and) sucrose distearate. Tubes of 2 g. Store between 15 and 25°C. Do not freeze.
Contraindications
ABREVA (docosanol cream 10%) is contraindicated in patients with known hypersensitivity to the product or any of its components.
Warnings
See Precautions.
Adverse Effects
In controlled clinical trials with ABREVA the most frequently reported adverse event was headache, which occurred in 10.4% of the patients treated with ABREVA and 10.7% of the patients treated with placebo. One or more local adverse reactions (application site reaction, rash, pruritus, dry skin, acne) were reported by 4.4% of patients treated with ABREVA and 3.2% of placebo treated patients. No evidence of contact sensitization or photoallergy was observed. See Table 1.
Overdose
For management of a suspected drug overdose, CPhA recommends that you contact your regional Poison Control Centre. See the eCPS Directories section for a list of Poison Control Centres.
Adverse reactions related to overdosage by topical application of ABREVA (docosanol cream 10%) are unlikely because of limited transcutaneous absorption. Similarly, poor oral absorption makes the occurrence of adverse reactions unlikely following ingestion of docosanol.
Dosage
ABREVA (docosanol cream 10%) should be applied topically 5 times/day as soon as possible, preferably at the prodrome or erythema stages, until the lesion is healed, up to a maximum of 10 days. Treatment is most effective if applied at the first symptoms (pain, itching, burning or tingling) or sign, (redness), prior to the formation of a papule (bump) or a blister. Apply with clean finger, rub in gently, wash hands following application. Avoid contaminating tip of tube.
