FINASTERIDE FOR PATTERN HAIRLOSS AND ISSUES SEXUAL SIDE EFFECTS

AThis piece caught my attention while searching for materials on Finasteride. Finasteride is commonly used either alone or part of the regime for the management of benign prostatic hyperplasia (BPH).

I believe not many people know that Finasteride could also be used in the treatment of hair loss. The article looked not only at this other use of Finasteride but also on its sexual side effects. It is by Venkataram Mysore  in an article titled “Finasteride and sexual side effects” published in the Indian Dermatol Online J. 2012 Jan-Apr; 3(1): 62–65. It noted that problems faced by health care providers while treating a patient of pattern hairloss were about the possible sexual side effects caused by Finasteride.

Pattern hair loss in males is androgenic in etiology. Antiandrogens such as Finasteride are therefore useful in the management of the condition. Androgens, especially testosterone increased the libido. Any medicine, which interferes with the action of androgens,is therefore assumed, to induce impotence.The precise role of androgen in penile erection needs to be fully elucidated. Even an individual with low testosterone levels can achieve erection. In addition to androgens, visual, olfactory, tactile, auditory, and imaginative stimuli influence the libido. The penile erection is mainly under the control of parasympathetic nervous system. Ejaculation and detumescence require an intact sympathetic system.

The androgens testosterone and dihydrotestosterone (DHT) have somewhat different actions. The enzyme, 5α-reductase (AR) converts testosterone to DHT. It exists in two isoenzyme forms. Type I5α-reductase is predominant in liver. Type II 5α-reductase is predominant in prostate, seminal vesicles, epididymes, hair follicles, and liver.

Within the hair follicle too, the two types (Type I & Type II) have different distributions. Type I 5AR, is present in the sebaceous gland, while type II 5AR is found on the outer root sheath of the hair follicles and dermal papillae. At all these sites, the testosterone is converted to DHT. The type II 5AR enzyme has a more significant role in pattern hairloss. The predominantenzyme in scalp skin is type I, largely because of localization to the sebaceous glands, which are large and plenty in scalp.

Finasteride is a specific and competitive inhibitor of Type II 5-AR, and has therefore a selective action on hair follicles. Scalp skin DHT levelsfall by more than 60% after administration of Finasteride, thereby suggesting that a significant amount of DHT found in scalp skin is derived from both local DHT production and circulating DHT. Thus, the effect of Finasteride on scalp DHT is likely because of its effect on both local follicular DHT levels as well as serum DHT levels. This explained why relatively small dose of Finasteride might be adequate therapeutically for pattern hair loss.

A number of studies have looked at the problem of side effects caused by Finasteride. These studies revealed that sexual adverse effects occur at the rates of 2.1% to 3.8%, with erectile dysfunction (ED) being the commonest followed by ejaculatory dysfunction and loss of libido. A key causal relation between Finasteride and sexual adverse effects is decreased ejaculatory volume because of predominant action of DHT on prostate.

The role of nocebo effect in the causation of ED due to Finasteride has been investigated. Nocebo effect referred to an adverse effect that results from the psychological awareness of the possibility of the side effects, but is not a direct result of the specific pharmacological action of the drug. In this study, the group informed about the sexual adverse effects of Finasteride reported increased incidence of ED, when compared to the group without information. The side effects were completely reversible in 5 days when the medicine was discontinued, confirming that nocebo effect had an influence in causation of side effects and reinforced the role of psychological factors.

A number of isolated case reports have also been published on the effect of low dose Finasteride on DNA changes in sperms, on motility, and sperm counts. These patients were under investigation for oligospermia and infertility when these findings were discovered. Significantly, these parameters improved after stopping the medicine.

The doses of Finasteride used for treating pattern hair loss is usually not more than 1mg per day as compared to 5mg used for BPH. The point was made that for the layperson the prospect of impotence while taking a drug for hairloss is daunting, however theoretical and small the risk of sexual side effects.Losing potency for gaining hair would not be an attractive proposition in spite of the value one may place on the risk…

In view of this, it was very important to properly counsel patients about the treatment. In particular, the following facts, among others, need to be stressed. The drug is probably the best available to treat androgenetic alopecia and the only one to address the root of the problem.Its effects are proven. Several studies have shown its safety over long duration of administration.

The dosage given (1 mg) is small and unlikely to cause side effects. Even in those cases where side effects were reported, the changes were found to be reversible.There are very few effective alternatives to the drug and it is therefore important for the patient not to stop the drug unless he experiences any side effects.The patient should contact the health care provider for any advice, should he experience a side effect.

The intake of the medicine is voluntary, as male pattern hair; loss is only a cosmetic condition. The health care provider should provide should give full information about the medicine to enable the patient to make an informed decision. It is better not to give the medicine to any patient who has prior history of oligospermia, infertility, particularly if he is newly married and is trying to raise a family.

For patients apprehensive about the side effects, it is worthwhile considering the administration of lower daily doses or staggered pulse doses of the medicine, to enhance patient adherence.

The plasma half-life of Finasteride is 6-8 hours and tissue binding is 4-5 days. Doses of 0.2 mg are adequate to suppress both scalp skin and serum DHT levels. While 0.2 mg caused 55% DHT suppression, 5 mg per day achieved 69% DHT suppression. Efficacy has been demonstrated for all ends for Finasteride at doses of 0.2 mg/day or higher, with 1 and 5 mg demonstrating similar efficacy that was superior to lower doses.

Finasteride may be therefore initially administered at 0.5 mg daily or one tablet alternate days, to gain the confidence of the patient and the 1 mg/day dosage may be restored once the patient is comfortable about the medicine.

For patients apprehensive about the side effects, it is worthwhile considering administration of lower daily doses or staggered pulse doses of the medicine, to enhance patient adherence. The plasma half-life of Finasteride is 6-8 hours and tissue binding is 4-5 days. Doses of 0.2 mg are adequate to suppress both scalp skin and serum DHT levels. While 0.2 mg caused 55% DHT suppression, 5 mg per day achieved 69% DHT suppression. Efficacy has been demonstrated for all ends for Finasteride at doses of 0.2 mg/day or higher, with 1 and 5 mg demonstrating similar efficacy that was superior to lower doses.

Finasteride may be therefore initially administered at 0.5 mg daily or one tablet alternate days, to gain confidence of the patient and the 1 mg/day dosage may be restored once patient is comfortable about the medicine.

DR. EDWARD O. AMPORFUL

CHIEF PHARMACIST

COCOA CLINIC