Pharmacology Update
Eflornithine Cream for Unwanted Facial Hair
By William T. Elliott, MD, FACP, and James Chan, PharmD, PhD
The fda has approved a cream for the reduc-tion of unwanted facial hair in women. Eflornithine is an inhibitor of ornithine decarboxylase, an enzyme that is found in hair follicles and is believed to be necessary for hair growth. Eflornithine cream will be co-marketed by Bristol and Gillette as Vaniqa.
Indications
Eflornithine cream is indicated for the reduction of unwanted facial hair in women. Usage should be limited to the face and adjacent involved areas under the chin.1
Dosage
A thin layer should be rubbed in thoroughly to affected areas of the face and adjacent areas under the chin twice daily at least eight hours apart. The area should not be washed for at least four hours. Hair removal techniques should be used as needed in conjunction with eflornithine cream.1
Eflornithine cream is supplied as 13.9%, 30 g.
Potential Advantages
Eflornithine cream does not appear to cause contact sensitization phototoxicity, or photosensitization reactions.1
Potential Disadvantages
Although eflornithine cream slows down the growth of hair, it does not permanently remove hair. Improvement is generally seen in 4-8 weeks but may take longer in some patients.1 If no improvement is seen in six months, treatment should be discontinued. After discontinuation of therapy, hair will return to pretreatment levels in about eight weeks. Side effects include acne (21.3%), pseudofolliculitis barbae (16.3%), and stinging (7.9%).
Comments
Eflornithine is an ornithine decarboxylase inhibitor that was developed as an antineoplastic agent and for the treatment of parasitic diseases such Trypanosoma brucei gambiense (sleeping sickness). Ornithine decarboxylase and S-adenosylmethionine decarboxylase are two enzymes involved in the synthesis of polyamines such as putrescine, spermidine, and spermine.2,3
Polyamines are alipathic cations with 2, 3, or 4 amino or amino groups. Animal studies suggest that ornithine decarboxylase is an important regulatory gene for the hair follicle and polyamines in general and spermidine in particular plays an important role in hair growth.3,4 There is a relatively good correlation between the rate of hair regrowth and skin ornithine decarboxylase activity.3
Efficacy of eflornithine was studied in two double-blind studies (n = 594; 393 with eflornithine and 201 with placebo). Decrease in hair growth was modest: 5% of patients had clear or almost clear areas compared to 0% for the vehicle, 27% had marked improvement in hair growth vs. 8% for the vehicle. Approximately 26% of patients in both the drug and placebo group showed improvement and 42% of actively treated patients showed no improvement compared to 66% for the vehicle. Physicians assessed the improvement or lack of improvement from baseline 48 hours after shaving. Caucasians appear to have greater benefit than noncaucasians (37% vs 22%).1
Clinical Implications
Eflornithine cream is an option, of somewhat modest efficacy, for the treatment of unwanted hair. It does not replace, but should be used in conjunction with other hair removing techniques such as shaving and plucking.
The cream is expected to cost the consumer about $50 for a 30 g, two-month supply.
References
1. Vaniqa Product Information. Bristol-Myers Squibb. July 2000.
2. Janne J, et al. Ann Med 1991;3:241-299.
3. Hynd PI, Nancarrow MJ. J Invest Dermatol 1996; 106(2):249-253.
4. Ogawa H, Hattori M. Curr Probl Dermatol 1983;11: 159-170.
5. Soler AP, et al. J Invest Dermatol 1996;106(5): 1108-1113.