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How
can finasteride be used to treat pattern baldness
Finasteride is the generic name for a drug that has been hitting
the news headlines as a treatment for androgenetic alopecia. The
trade name "propecia" is used for this new hair loss treatment.
You may also have heard another trade name "proscar" which
is the same thing as finasteride/propecia but proscar is specifically
used for men with prostate complications. propecia and proscar are
the trade marks of Merck & Co., Inc., USA.
Finasteride was originally developed by Merck as a drug to treat
enlarged prostate glands. During the trials on men with prostate
problems an intriguing side effect of hair growth was observed.
With Finasteride passed as a prostate drug by the Federal Drug Administration
(FDA), Merck decided to pursue the possibility of developing finasteride
as the hair treatment propecia.
As described elsewhere, 5 alpha-reductase is an important enzyme
found in and around hair follicles that converts testosterone into
the far more potent dihydrotestosterone. Dihydrotestosterone is
the single most important hormone that adversely affects scalp hair
follicles and leads to androgenetic alopecia. There are at least
two types of the 5 alpha-reductase enzyme. Type one (I) is believed
to be more active than type two (II) in androgenetic alopecia.
 Propecia
is a type II 5 alpha reductase inhibitor. With reduced production
of type II 5 alpha-reductase there seems to be much less testosterone
converted to dihydrotestosterone. With less dihydortestosterone
binding to hair follicle androgen receptors so there seems to be
reduced hair follicle miniaturization in androgenetic alopecia.
Originally many dermatologists questioned whether a type II 5 alpha
reductase inhibitor would be truly effective in treating androgenetic
alopecia. Type I 5 alpha reductase is generally unaffected by the
Propecia drug and is still converting some testosterone to dihydrotestosterone.
However, if the clinical trial results are to be believed then dermatologists
concerns were unfounded.
Phase III trials of propecia have been ongoing for several years.
According to propecia manufacturer Merck, a placebo controlled double
blind study of propecia initially involved 60 dermatology clinics
(33 in the USA, 27 non-USA) and 1533 male volunteers in the first
year. Of these volunteers 1215 continued in the program for a second
year. The men were between 18 to 41 years of age at the start of
the study and had androgenetic alopecia defined as type III, IV
or V on the Hamilton/Norwood scale. The men were given either 1mg
of propecia per day or a placebo. Propecia is taken as a tablet
orally and works systemically.
Both subjective and objective tests were used regularly through
the study to evaluate hair growth. Subjective analysis involved
each patient answering a validated questionnaire to examine their
views on the success/failure of their treatment. Objective analysis
involved observation of a given target scalp area marked in the
same place on each patient with tattoo dots. The evaluation included
consideration of terminal hair density and an overall evaluation
of scalp skin coverage looking at density, linear hair growth, diameter,
duration of anagen, and hair replacement kinetics. Global photographs
were also taken regularly for semi quantitative analysis of overall
cosmetic changes. Both subjective and objective data were analyzed
by dermatologists who were unaware of which individual was receiving
Propecia and which was using a placebo.
The first year results of the phase III trial were; a mean density
increase to 86 hairs per inch diameter in the marked area of scalp
(+11%) for those using propecia. In contrast placebo users had a
mean density decrease of 21 hairs (-2.7%). This apparently resulted
in a mean difference of 107 more terminal hairs per inch diameter
circular target in the propecia users compared to control placebo
users. Blind assessment of the global photographs (semi quantitative
analysis) after one year suggested total hair growth improvements
in 48% of men using propecia and 7% of placebo users. 30% of propecia
users were described as slightly improved and 18% as moderately
or greatly improved. 6% on placebo were slightly improved and 1%
moderately or greatly improved.
In the second year of study there was no increase in number of
hairs growing on the marked scalp area for propecia users so hair
density remained the same. However, semi-quantitative analysis of
global photographs suggested continued improvement in general hair
coverage in the second year of use. The improvement was due to hair
follicles present in the first year's analysis developing a prolonged
anagen growth phase and increased hair fiber diameter. Placebo users
continued to have gradual progression of androgenetic alopecia and
reduced hair coverage.
Questionnaires showed that diminished sexual function was the
most common side effect of propecia, 0.5% more common than observed
in the placebo group. This side effect resolved if the individual
stopped using Propecia. Propecia only worked for as long as it was
used. Any individuals who stopped using the drug reverted to progressive
androgenetic hair loss. The studies indicated that age of the individual
made no difference to the success rate and the duration of the hair
loss made no difference. As expected those with least hair loss
had the least improvement when using the drug. Caucasians were observed
to have a better response to Finasteride compared to Asians or African-Americans.
So, propecia works for a proportion of men but by no means all men
with androgenetic alopecia. It is most likely to stop further hair
loss and for a lucky minority the drug actually encourages hair
regrowth.
Splitting finasteride pills (proscar) for use in androgenetic
alopecia treatment is common practice in countries where propecia
is not yet available. Proscar tablets are each 5mgs finasteride
dose. 5mgs may be optimum dose for urinogenital treatment but it
is more than is necessary for androgenetic alopecia. Propecia tablets
are 1mg dose each so splitting proscar tablets in 4 or 5 is a common
recommendation of non US dermatologists prescribing finasteride.
How
can finasteride be used to treat pattern baldness
- Whiting
DA, Waldstreicher J, Sanchez M, Kaufman KD. Measuring reversal
of hair miniaturization in androgenetic alopecia by follicular
counts in horizontal sections of serial scalp biopsies: results
of finasteride 1 mg treatment of men and postmenopausal women.
J Investig Dermatol Symp Proc. 1999 Dec;4(3):282-4.
- McClellan
KJ, Markham A. Finasteride: a review of its use in male pattern
hair loss. Drugs. 1999 Jan;57(1):111-26.
- Kaufman
KD, Olsen EA, Whiting D, Savin R, DeVillez R, Bergfeld W, Price
VH, Van Neste D, Roberts JL, Hordinsky M, Shapiro J, Binkowitz
B, Gormley GJ. Finasteride in the treatment of men with androgenetic
alopecia. Finasteride Male Pattern Hair Loss Study Group. J
Am Acad Dermatol. 1998 Oct;39(4 Pt 1):578-89.
- Leyden
J, Dunlap F, Miller B, Winters P, Lebwohl M, Hecker D, Kraus
S, Baldwin H, Shalita A, Draelos Z, Markou M, Thiboutot D, Rapaport
M, Kang S, Kelly T, Pariser D, Webster G, Hordinsky M, Rietschel
R, Katz HI, Terranella L, Best S, Round E, Waldstreicher J.
Finasteride in the treatment of men with frontal male pattern
hair loss. J Am Acad Dermatol. 1999 Jun;40(6 Pt 1):930-7.
- Roberts
JL, Fiedler V, Imperato-McGinley J, Whiting D, Olsen E, Shupack
J, Stough D, DeVillez R, Rietschel R, Savin R, Bergfeld W, Swinehart
J, Funicella T, Hordinsky M, Lowe N, Katz I, Lucky A, Drake
L, Price VH, Weiss D, Whitmore E, Millikan L, Muller S, Gencheff
C, et al. Clinical dose ranging studies with finasteride, a
type 2 5alpha-reductase inhibitor, in men with male pattern
hair loss. J Am Acad Dermatol. 1999 Oct;41(4):555-63.
- Drake
L, Hordinsky M, Fiedler V, Swinehart J, Unger WP, Cotterill
PC, Thiboutot DM, Lowe N, Jacobson C, Whiting D, Stieglitz S,
Kraus SJ, Griffin EI, Weiss D, Carrington P, Gencheff C, Cole
GW, Pariser DM, Epstein ES, Tanaka W, Dallob A, Vandormael K,
Geissler L, Waldstreicher J. The effects of finasteride on scalp
skin and serum androgen levels in men with androgenetic alopecia.
J Am Acad Dermatol. 1999 Oct;41(4):550-4.
- Steiner
JF.Clinical pharmacokinetics and pharmacodynamics of finasteride.
Clin Pharmacokinet. 1996 Jan;30(1):16-27.
- Diani
AR, Mulholland MJ, Shull KL, Kubicek MF, Johnson GA, Schostarez
HJ, Brunden MN, Buhl AE. Hair growth effects of oral administration
of finasteride, a steroid 5 alpha-reductase inhibitor, alone
and in combination with topical minoxidil in the balding stumptail
macaque. J Clin Endocrinol Metab. 1992 Feb;74(2):345-50.
- Rhodes
L, Harper J, Uno H, Gaito G, Audette-Arruda J, Kurata S, Berman
C, Primka R, Pikounis B. The effects of finasteride (Proscar)
on hair growth, hair cycle stage, and serum testosterone and
dihydrotestosterone in adult male and female stumptail macaques
(Macaca arctoides). J Clin Endocrinol Metab. 1994 Oct;79(4):991-6.
- Kaufman KD. Finasteride, 1 mg (Propecia),
is the optimal dose for the treatment of men with male pattern
hair loss. Arch Dermatol. 1999 Aug;135(8):989-90.
- Thiboutot D. Propecia dosages. Arch Dermatol.
1999 Nov;135(11):1417.
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