Method of action:
Medically reviewed by Oliinyk Elizabeth Ivanovna, PharmD. Last updated on 2022-03-17
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Treatment of early stages (prodrome or erythema phase) of recurrent labial herpes simplex infection (cold sores) in immunocompetent adults.
Route of Administration: Cutaneous use
Adults and adolescents aged 12 years and over:
Apply a thin film carefully over the entire cold sore 5 times a day (approximately every 3 hours during waking hours).
Treatment must begin as soon as possible after the first cold sore symptoms or signs appear (pain, burning/itching/tingling or redness) as efficacy has not been demonstrated when the treatment is initiated at the stage of an already developed blister or ulcer.
Treatment should continue until healing has occurred, usually 4 to 6 days, or for a maximum of 10 days.
No special dose recommendation.
The safety and efficacy of Blistex Cold Sore Cream in children aged younger than 12 years have not been established.
Dosage in renal failure:
No dose adjustments necessary due to negligible topical absorption.
Hypersensitivity to the active substance (docosanol) or to any of the excipients.
Avoid application close to or in the eyes.
Should only be used for cold sores on the mouth and face.
Must not be used to treat genital or ocular herpes infections
Avoid transmitting the virus, particularly when active lesions are present.
The cream should not be used in immuno compromised patients.
Treatment with the cream should not be initiated at the stage of an already developed blister or ulcer.
If the recurrent cold sore is particularly severe, consult doctor.
Immunocompromised patients should consult a pharmacist or doctor concerning treatment of any infection, including cold sores.
There is no treatment experience available for the use in children below the age of 12 years and only limited experience in adolescent (aged 12-18 years). It is recommended that the cream should not be used in children under 12 years.
This formulation contains propylene glycol and may cause skin irritation.
Due to its negligible absorption docosanol has no influence on the ability to drive and use machines.
Very common (>1/10)
Common (>1/100 to <1/10)
Uncommon (>1,000 to <1/100)
Rare (>1/10,000 to <1/1,000)
Very rare (<1/10,000)
Not known (cannot be estimated from the available data).
Results from clinical trials of the treatment of recurrent labial herpes simplex demonstrate no difference in the frequency or type of undesirable effects in patients treated with Blistex Cold Sore Cream or placebo.
Nervous system disorders
Very common: Headache (10.4% of docosanol-treated patients and 10.7% of placebo-treated patients).
General disorders and administration site conditions
Common: Application site adverse reactions which include dry skin, rashes and skin disorders (2.9% of docosanol-treated patients and 2.3% of placebo-treated patients).
Facial oedema has also been reported but these application site adverse reactions are consistent with normal facial reactions experienced with cold sores.
Reporting of suspected adverse reactions
Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme, website: www.mhra.gov.uk/yellowcard.
Adverse reactions related to overdose by topical application of Blistex Cold Sore Cream are unlikely because of negligible percutaneous absorption. Similarly, poor oral absorption makes the occurrence of adverse reactions unlikely following ingestion of docosanol.
Pharmacotherapeutic group: Chemotherapeutics for topical use, antivirals
ATC code: D06BB11
The exact mechanism of the antiviral activity of docosanol is unknown. In vitro studies indicate that docosanol affects the fusion between the virus and the plasma membrane, which inhibits intracellular uptake and replication of virus. In vitro studies demonstrate that docosanol-treated cells resist infection by lipid-enveloped viruses such as HSV-1. Docosanol has no effect against non-enveloped viruses. Docosanol 10 % was compared to placebo (containing polyethylene glycol) in two randomised, double-blind, controlled clinical trials. In one study, 370 adults were randomised. Subjects started with treatment in the prodrome or erythema phase of an acute recurrence of orofacial herpes. The ITT population consisted of 183 subjects for docosanol and 183 subjects for placebo. The median time to complete healing was 4.0 days in the docosanol group and 4.7 days in the placebo group a difference of 18.9 hours (p=0.0235; p=0.010 with covariate adjustment). In the second study, 373 adults were randomised. Subjects started with treatment in the prodrome or erythema phase of an acute recurrence of orofacial herpes. The ITT population consisted of 187 subjects for docosanol and 184 subjects for placebo. The median time to complete healing was 4.3 days in the docosanol group and 4.9 days in the placebo group a difference of 15.9 hours (p=0.1529; p=0,008 with covariate adjustment). In studies with treatment initiation at stages later than the prodromal or erythema stage, efficacy was not demonstrated.
Under conditions reflecting normal clinical use of Blistex Cold Sore Cream, docosanol could not be quantified (limit of quantification, LOQ = 10 ng/ml) in the plasma of treated patients. Ten women with active labial herpes simplex were treated with Blistex Cold Sore Cream. After a single dose on study day 1 and after multiple doses (five times daily, study days 2-3), blood samples were withdrawn up to 24 hours after treatment and analysed for docosanol. Of the 209 plasma samples analysed, the docosanol level was below the LOQ in 208 and exactly at the LOQ in one sample.
Docosanol is metabolized to docosanoic acid, its major metabolite. Both docosanol and docosanoic acid are endogenous components of cell membranes in man, particularly in erythrocytes, brain, nerve myelin sheath, lung, and kidney.
Preclinical data revealed no special hazard for humans based on conventional studies of safety, pharmacology, repeated dose toxicity, genotoxicity and toxicity to reproduction.
No special requirements.