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Sunday, November 29, 2020

MINOXIDIL

 

            Minoxidil is a medication used for the treatment of high blood pressure and male-pattern hair loss.It is an antihypertensive vasodilator.It is available as a generic medication by prescription in oral tablet form and over the counter as a topical liquid or foam. 

 
  Use :           Minoxidil, applied topically, is widely used for the treatment of hair loss. It is effective in helping promote hair growth in people with androgenic alopecia regardless of sex. Minoxidil must be used indefinitely for continued support of existing hair follicles and the maintenance of any experienced hair regrowth.

 

 

 How to use 

Mechanism of action 

       The mechanism by which minoxidil promotes hair growth is not fully understood. Minoxidil is a potassium channel opener, causing hyperpolarization of cell membranes. Theoretically, by widening blood vessels and opening potassium channels, it allows more oxygen, blood, and nutrients to the follicles. This may cause follicles in the telogen phase to shed, which are then replaced by thicker hairs in a new anagen phase. Minoxidil is a prodrug that is converted by sulfation via the sulfotransferase enzyme SULT1A1 to its active form, minoxidil sulfate. Minoxidil is less effective when the area of hair loss is large. In addition, its effectiveness has largely been demonstrated in younger men who have experienced hair loss for less than 5 years. Minoxidil use is indicated for central (vertex) hair loss only. Two clinical studies are being conducted in the US for a medical device that may allow patients to determine if they are likely to benefit from minoxidil therapy. 

History 

       Minoxidil was first introduced as an oral medication for the treatment of severe and recalcitrant hypertension in the 1970s.1 Coincidentally, physicians observed hair regrowth and generalized hypertrichosis in balding patients, which led to the development of a topical minoxidil formulation for treating androgenetic alopecia (AGA) first in male and then in female individuals. The 2% minoxidil solution was first launched in the market in 1986, followed by the 5% solution in 1993.2 Despite its global acceptance for over 30 years, the mechanism underlying the hair growth-promoting effects of minoxidil remains to be fully elucidated. We aimed to review and update critical clinical information on topical minoxidil including the pharmacology, mechanism of action, clinical efficacy, and adverse effects.

 

Pharmacology of Topical Minoxidil

       Minoxidil is a piperidino-pyrimidine derivative, with the following chemical structure: 2,6-diamino-4-piperidinopyrimidine-1-oxide (C9H15N5O) (Figure 1).2 Minoxidil solution (MS) contains inactive ingredients, including water, as well as ethanol and propylene glycol (PG), which are used as vehicles to enhance the solubility of minoxidil.3 PG facilitates efficient drug delivery into the hair follicles; however, its frequent induction of local irritation led to the development of a PG-free minoxidil foam (MF). The non-medical ingredients in the foam formulation include cetyl alcohol, stearyl alcohol, and butylated hydroxytoluene.4 




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