Topically applied minoxidil in baldness

Pharmacological Management of Pattern Hair Loss

Pattern hair loss (PHL) is a condition that worsens with time and the only way it can be slowed down is with pharmacological intervention. Pharmacological treatments for PHL, from an evidenced-based perspective with respect to safety and efficacy, are limited to only two drugs, minoxidil and finasteride. However, there are a host of drugs being used, off-label with limited evidence. This article attempts to review the literature on this topic, and the authors add to this, with their experience of over two decades on incorporating pharmacologic treatments along with hair transplantation in their management of PHL.

Minoxidil: a comprehensive review

Topical minoxidil (5% foam, 5% solution, and 2% solution) is FDA-approved for androgenetic alopecia (AGA) in men and women.Mechanism of action: Minoxidil acts through multiple pathways (vasodilator, anti-inflammatory agent, inducer of the Wnt/β-catenin signaling pathway, an antiandrogen), and may also affect the length of the anagen and telogen phases.Pharmacokinetics: Approximately 1.4% of topical minoxidil is absorbed through the skin. Minoxidil is a prodrug that is metabolized by follicular sulfotransferase to minoxidil sulfate (active form). Those with higher sulfotransferase activity may respond better than patients with lower sulfotransferase activity.Clinical efficacy (topical minoxidil): In a five-year study, 2% minoxidil exhibited peak hair growth in males at year one with a decline in subsequent years. Topical minoxidil causes hair regrowth in both frontotemporal and vertex areas. The 5% solution and foam were not significantly different in efficacy from the 2% solution.Oral and Sublingual minoxidil (not FDA approved; off-label): After 6 months of administration, minoxidil 5 mg/day was significantly more effective than topical 5% and 2% in male AGA. Low-dose 0.5-5 mg/day may also be safe and effective for female pattern hair loss and chronic telogen effluvium. Sublingual minoxidil may be safe and effective in male and female pattern hair loss.

New ethanol and propylene glycol free gel formulations containing a minoxidil-methyl-β-cyclodextrin complex as promising tools for alopecia treatment

New topical totally aqueous formulations that improve the low water solubility of minoxidil and realize an adequate permeability of drug in the skin are proposed. These formulations are lacking in propylene glycol and alcohol that are the principal irritant ingredients present in minoxidil commercial solutions. In order to enhance poor water solubility of minoxidil randomly methyl-β-cyclodextrin was used, and four hydrogels such as, calcium alginate, sodium alginate, carbopol 934 and hydroxyethylcellulose were utilized to ensure a prolonged time of contact with the scalp. The inclusion complex minoxidil/methyl-β-cyclodextrin with a molar ratio 1:1 was obtained by freeze drying and evaluated by NMR, FT-IR and DSC analysis. An apparent stability constant of formed inclusion complex was calculated by phase solubility diagram and its value was 400 M(-1). The solid inclusion complex was used to prepare gel formulations with similar dose to minoxidil commercial solution. The gels were evaluated for various technological parameters including rheological behavior, in vitro drug release and ex vivo permeation through pig skin. The best performance was observed for the calcium alginate formulation.

Medical treatments for male and female pattern hair loss

Male and female pattern hair loss affects a large percentage of the population, and patients frequently present for treatment of this to their dermatologist. Here we review the many treatments available for hair loss. We review the evidence for each, and outline the most effective treatment strategies for both men and women.

LEARNING OBJECTIVE

At the conclusion of this article, the reader should be able to describe the most effective treatments for hair loss, understand their mechanism(s) of action, and explain which treatments are the best in different settings.

Prostaglandin-induced hair growth

Latanoprost, used clinically in the treatment of glaucoma, induces growth of lashes and ancillary hairs around the eyelids. Manifestations include greater thickness and length of lashes, additional lash rows, conversion of vellus to terminal hairs in canthal areas as well as in regions adjacent to lash rows. In conjunction with increased growth, increased pigmentation occurs. Vellus hairs of the lower eyelids also undergo increased growth and pigmentation. Brief latanoprost therapy for 2-17 days (3-25.5 microg total dosage) induced findings comparable to chronic therapy in five patients. Latanoprost reversed alopecia of the eyelashes in one patient. Laboratory experiments with latanoprost have demonstrated stimulation of hair growth in mice and in the balding scalp of the stumptailed macaque, a primate that demonstrates androgenetic alopecia. The increased number of visible lashes is consistent with the ability of latanoprost to induce anagen (the growth phase) in telogen (resting) follicles while inducing hypertrophic changes in the involved follicles. The increased length of lashes is consistent with the ability of latanoprost to prolong the anagen phase of the hair cycle. Correlation with laboratory studies suggests that initiation and completion of latanoprost hair growth effects occur very early in anagen and the likely target is the dermal papilla.

Generalized hypertrichosis after treatment with topical minoxidil

Generalized hypertrichosis is a common side-effect of oral minoxidil treatment for hypertension. However, hypertrichosis is uncommon after treatment with topical minoxidil for alopecia, and normally only occurs in areas close to the site of application. A 16-year-old girl is presented who developed generalized hypertrichosis 3 months after applying topical minoxidil for treatment of diffuse alopecia in doses greater than that prescribed. Four months after discontinuing treatment, the abnormal hair gradually diminished and disappeared.

Animal models of androgen-dependent disorders of the pilosebaceous apparatus. 1. The androchronogenetic alopecia (AGA) mouse as a model for male-pattern baldness

The androchronogenetic alopecia (AGA) mouse if a mutant strain which expresses androgen-dependent baldness. Daily s.c. injection of testosterone (T) induced thinning of the hair coat along the upper dorsum after 4 weeks of treatment. After 12 to 14 weeks this diffuse alopecia eventually eveloped into a bald area which extended to the middorsum. Dihydrotestosterone was more effective than T in stimulating the onset of AGA. In this model, T produced the alopecia by decreasing the rate of hair growth, decreasing the duration of anagen, and markedly prolonging the duration of telogen. When applied topically at a concentration of 5%, cyproterone acetate delayed the progression of the T-mediated hair loss. However, this inhibitory effect occurred through systemic means as evidenced by decrease in the size of the submaxillary gland. Chronic feeding of androgen-treated female AGA mice with a diet containing 0.01% minoxidil also inhibited the development of alopecia. Skin and core temperatures were found to be higher in minoxidil-treated animals than in the placebo-treated controls. Minoxidil at a topical dose of 1% did not produce any effect. Increasing the dose to 2% caused a slight retardation of the development of alopecia. However, a 60% inhibition was observed at a topical dose of 5% minoxidil after 12 weeks of treatment (p less than 0.03). The data demonstrate that hair loss in the AGA mouse is androgen dependent and that this mutant strain can serve as a suitable model for the screening of compounds, such as antiandrogens and vasodilators, which may influence the balding process.

Nongenotoxicity of minoxidil in murine hair follicles as determined by the nuclear aberration assay

A 1-cm2 area on the back of CD1 mice was prepared for topical application of minoxidil, N-methyl-N-nitrosourea (MNU), or cyclophosphamide (CY) by clipping or plucking hair from a patch of skin. Plucking stimulates hair follicle cell division while clipping does not. Minoxidil was topically administered for 8 consecutive days. CY or MNU was administered topically once on the eighth day postplucking. The incidence of nuclear aberrations and mitotic figures were measured in hair follicles while frequency of micronuclei and the ratio of RBC/PCE were measured in the bone marrow. Results with minoxidil showed no increase in either nuclear aberrations in the hair follicle or micronuclei in the bone marrow. These results suggest that topically applied minoxidil is not genotoxic. In contrast, a dose-dependent effect of MNU on the incidence of nuclear aberrations in the hair follicle was seen. CY induced a dose-dependent increase in the incidence of micronuclei in the bone marrow and in nuclear aberrations in the hair follicle after topical application. Minoxidil applied to clipped mice significantly increased the incidence of mitotic figures above that seen in both the clipped and plucked controls. This suggests that minoxidil is a mitogenic agent in the hair follicle. These findings are consistent with the success of topically applied minoxidil in the treatment of alopecia areata.

Long-term efficacy of topical minoxidil in male pattern baldness

A 24-month clinical trial, begun on a double-blind basis, was conducted in 153 men with discernible male pattern baldness of the crown with the use of either topically applied placebo, 2% minoxidil, or 3% minoxidil solution. After 4 months the patients using placebo were switched to 3% minoxidil solution. At 12 months, there were statistically significant increases in terminal hair growth within a 1-inch target area in those treated with 2% or 3% minoxidil solution, in comparison with baseline counts. However, there were few patients who had appreciable cosmetic restoration. At 12- and 24-month intervals, progressive regression or stabilization of the size of the bald area was noted in the majority of patients. This therapeutic or preventive effect was statistically significant. The data on actual target area hair counts suggested that the 2% minoxidil solution was equal to or more efficacious than the 3% minoxidil solution. Baseline vital signs and laboratory parameters remained essentially unchanged. Topical minoxidil was well tolerated, with no serious drug-related adverse reactions noted during the study.

Long-term follow-up of men with male pattern baldness treated with topical minoxidil

Forty-one men with male pattern baldness completed 132 study weeks (2 years 9 months) with topical minoxidil and had follow-up 1-inch target-area vertex scalp hair counts. Initially these men were treated with either twice-daily 2% topical minoxidil for 12 months or 3% topical minoxidil for 8 to 12 months (one third of the subjects received placebo for the first 4 months). After 12 months all subjects continued to apply 3% topical minoxidil twice daily for 1 more year, after which they were randomized to once- versus twice-daily topical minoxidil for an additional 9 months. Those subjects who changed to once-daily application of topical minoxidil at 2 years had a mean change from baseline nonvellus hair count at 1 year of 291.2 (range of hairs four to 553) and at 2 years 9 months of 235 (two to 592 hairs). Those subjects who continued with twice-daily application of topical minoxidil throughout the study had a mean change from baseline nonvellus hair count at 1 year of 323 (15 to 589 hairs) and 335 (13 to 808 hairs) at 2 years 9 months with maintenance topical minoxidil. There were subjects on both maintenance schedules of topical minoxidil who lost some of the nonvellus hair they had initially gained with topical minoxidil; however, there was a greater mean loss in those patients following the once-daily versus twice-daily topical minoxidil regimen (p = 0.05). No subject lost nonvellus target hair as compared with baseline.(ABSTRACT TRUNCATED AT 250 WORDS)

Topical minoxidil. A preliminary review of its pharmacodynamic properties and therapeutic efficacy in alopecia areata and alopecia androgenetica

When minoxidil is administered orally for periods in excess of 1 month, hypertrichosis occurs as a side effect in a majority of patients. Consequently, topical minoxidil has been developed to try to improve hair growth in patients with alopecia areata and alopecia androgenetica. Preliminary studies have shown that topical minoxidil promotes cosmetically acceptable hair regrowth in a variable proportion of patients with alopecia areata. Data from a large multicentre trial indicate that cosmetically worthwhile results are achieved in about one-third of subjects with alopecia androgenetica after 1 year of treatment. A much higher proportion (about 80%) of patients with alopecia androgenetica exhibited some non-vellus hair regrowth after 1 year, and whether more of these patients would develop a cosmetically acceptable result with a longer treatment period is an important area of future investigation. Initial indications suggest that less severe disease is a predictor of likely response. Thus, topical minoxidil would seem to be a useful treatment modality for patients with alopecia androgenetica--a disease for which no other safe and effective drug therapy exists. Results from treating patients with alopecia areata with topical minoxidil, although encouraging, have been more variable and require further evaluation. Even though a number of questions remain to be answered about topical minoxidil (as would be expected at this stage in its development), it would seem to be the first available drug with the potential to promote substantial hair regrowth in these divergent diseases.

The determination of minoxidil in human serum by high-performance liquid chromatography with amperometric detection

An ion-pairing reversed-phase HPLC assay employing amperometric detection has been developed for the determination of free minoxidil (MNX) in human serum. The drug is isolated from the serum and concentrated by solid phase extraction with a disposable cartridge column containing ethylsilane (C2) bonded phase packing material. The average absolute recovery from serum was 85%. The HPLC separation is performed on a Sperisorb-C(8) column, using n-octanesulphonic acid as the pairing ion. The method exhibits linear behaviour from 0.3 to 100 ng/ml for spiked serum samples. The average daily relative standard deviations of replicate samples at the 0.75 and 2.0 ng/ml levels were 9.6 and 6.4%, respectively. Utilizing a 1 ml sample the limit of detection (S/N > or = 3) was 0.3 ng/ml.

Topical minoxidil for male pattern baldness

Significant hair growth occurred in 53% of the 81 patients completing a 1 year trial of topical minoxidil. The average reduction in the diameter of the balding crown was 3.48 cm for all patients. There were no minoxidil related changes in laboratory tests during the study period. Psychosocial studies of our patients indicate that 95% assessed the effectiveness of topical minoxidil as moderate or excellent. The majority of those participating in the study thought that their personal presentation of self was of equal or greater importance than their work performance. It was concluded that topical minoxidil has the potential to improve male pattern baldness significantly without apparent risk and to be a means by which individual presentation of self may be improved.