Post by Mod on Feb 23, 2010 21:00:07 GMT -5
From Wikipedia:
Minoxidil (trade names Rogaine and Regaine) is a vasodilator medication known for its ability to slow or stop hair loss and promote hair regrowth. It is available over the counter for treatment of androgenic alopecia, among other baldness treatments, but measurable changes disappear within months after discontinuation of treatment.
HISTORY
Minoxidil was first used exclusively as an oral drug (trade name Loniten) to treat high blood pressure. It was, however, discovered to have an interesting side-effect: [1]Minoxidil may cause increased growth or darkening of fine body hairs. If this is bothersome, consult your doctor. When the medication is discontinued, the hair will return to normal within 30 to 60 days. Upjohn Corporation produced a topical solution that contained 2% minoxidil to be used to treat baldness and hair loss, under the brand name Rogaine in the United States and Canada, and Regaine in Europe and the Asia-Pacific. Treatments usually include a 5% concentration solution that is designed for men, whereas the 2% concentration solutions are designed for women. The patent on minoxidil expired on February 13, 1996.[2]
In 2007 a new foam-based formulation of 5% minoxidil was shown to be as effective as the liquid-based treatment for male pattern baldness.[3]
While the drug is available in the United Kingdom, it cannot be prescribed on the NHS, so patients must either buy it over-the-counter or have a private prescription for it.[4]
RESULTS
One study in healthy males aged 18–50 years with androgenetic alopecia (male pattern baldness) found that compared to a baseline of 103 to 106 hairs/cm2, those who applied a 5% solution of minoxidil for 32 weeks increased their non-vellus hair counts by an average of 39 hairs/cm2, in contrast to 5 hairs/cm2 in subjects who received a placebo.[5]
MECHANISM
The mechanism by which minoxidil promotes hair growth is not fully understood. Minoxidil is a potassium channel opener, causing hyperpolarization of cell membranes. Minoxidil is less effective when there is a large area of hair loss. In addition, its effectiveness has largely been demonstrated in younger men (18 to 41 years of age). Minoxidil use is indicated for central (vertex) balding only.[6]
Minoxidil is also a vasodilator[citation needed]. It is speculated that by widening blood vessels and opening potassium channels, it allows more oxygen, blood and nutrients to the follicle. This can also cause follicles in the telogen phase to shed, usually soon to be replaced by new, thicker hairs (in a new anagen phase).
SIDE EFFECTS
As a drug to combat hair loss, the most common side effect is itchy scalp. Alcohol present in topical preparations may dry the scalp, resulting in dandruff.[7] Side effects of oral minoxidil may include swelling of the face and extremities, rapid and irregular heartbeat, lightheadedness, cardiac lesions, and focal necrosis of the papillary muscle and subendocardial areas of the left ventricle.[8] There have been cases of allergic reactions to minoxidil or the non-active ingredient propylene glycol, which is found in some forms of topical Rogaine.
Ironically, hair loss is a common side effect of minoxidil treatment.[9] Manufacturers note that minoxidil-induced hair loss is a common side effect and describe the process as 'shedding'. Although this phenomenon demonstrates that minoxidil is indeed affecting hair follicles, manufacturers offer no guarantee that the new hair loss will be replaced with hair growth.
The speculated reason for this "shedding" is the encouragement of hairs already in the telogen phase to shed early, before often beginning a fresh, healthier anagen phase.
TOXIC EFFECTS
Minoxidil is highly toxic to cats and may cause death.[10][11]
APPLICATION
Minoxidil products involve contact with hair strands, which may cause problems with hair styling since minoxidil must be in an alcohol solution. To keep the minoxidil solution from affecting normal hair styling applications, it can be washed out after at least 40 minutes, although this will decrease the hair regrowth effect. For maximum effect, the solution should be in contact with the scalp for four hours before being washed out. If the solution is not a problem, hair styling devices can be used as soon as the minoxidil solution has dried.
Minoxidil usually needs to be applied regularly (once or twice daily) for hair gained to be maintained. It does not seem capable of reducing DHT or the enzyme responsible for it's accumulation around the hair follicle, 5-alpha reductase, which are the main causes of male pattern baldness in genetically susceptible individuals. Therefore, when treatment is stopped, the DHT already accumulated around the follicle has it's expected effect, and the follicle usually shrinks again and eventually dies.
Minoxidil solutions are sold under many brand names. Many high priced as well as generic brands of minoxidil regrowth solutions exist and do not differ in their active ingredient or concentration (except differing versions within each brand).
REFERENCES
^ www.medicinenet.com/minoxidil-oral/article.htm.
^ "Grant v. Pharmacia & Upjohn Co.". ca10.washburnlaw.edu/cases/2002/12/01-1509.htm. Retrieved 2009-01-17.
^ Olsen EA, Whiting D, Bergfeld W, Miller J, Hordinsky M, Wanser R, Zhang P, Kohut B (2007). "A multicenter, randomized, placebo-controlled, double-blind clinical trial of a novel formulation of 5% minoxidil topical foam versus placebo in the treatment of androgenetic alopecia in men". J Am Acad Dermatol. 57: 767. doi:10.1016/j.jaad.2007.04.012. PMID 17761356.
^ Drug Tariff, retrieved 2009/04/11
^ Rogaine Topical Solution 5%, at Pharmcom, 27 June 2009.
^ Medical Treatments for Balding in Men American Family Physician April 15, 1999
^ "Dandruff and Seborrheic Dermatitis". Medscape.com. www.medscape.com/viewarticle/407641. Retrieved 2009-10-09.
^ "Minoxidil Official FDA information, side effects and uses". Drugs.com. www.drugs.com/pro/minoxidil.html.
^ "Rogaine FAQs". www.rogaine.com/men/faq#question-9.
^ Camille DeClementi; Keith L. Bailey, Spencer C. Goldstein, and Michael Scott Orser (December 2004). "Suspected toxicosis after topical administration of minoxidil in 2 cats". Journal of Veterinary Emergency and Critical Care 14 (4): 287–292. doi:10.1111/j.1476-4431.2004.04014.x.
^ "Minoxidil Warning". ShowCatsOnline.com. www.showcatsonline.com/x/minoxidil.shtml. Retrieved 2007-01-18. "Very small amounts of Minoxidil can result [in] serious problems or death"
Minoxidil (trade names Rogaine and Regaine) is a vasodilator medication known for its ability to slow or stop hair loss and promote hair regrowth. It is available over the counter for treatment of androgenic alopecia, among other baldness treatments, but measurable changes disappear within months after discontinuation of treatment.
HISTORY
Minoxidil was first used exclusively as an oral drug (trade name Loniten) to treat high blood pressure. It was, however, discovered to have an interesting side-effect: [1]Minoxidil may cause increased growth or darkening of fine body hairs. If this is bothersome, consult your doctor. When the medication is discontinued, the hair will return to normal within 30 to 60 days. Upjohn Corporation produced a topical solution that contained 2% minoxidil to be used to treat baldness and hair loss, under the brand name Rogaine in the United States and Canada, and Regaine in Europe and the Asia-Pacific. Treatments usually include a 5% concentration solution that is designed for men, whereas the 2% concentration solutions are designed for women. The patent on minoxidil expired on February 13, 1996.[2]
In 2007 a new foam-based formulation of 5% minoxidil was shown to be as effective as the liquid-based treatment for male pattern baldness.[3]
While the drug is available in the United Kingdom, it cannot be prescribed on the NHS, so patients must either buy it over-the-counter or have a private prescription for it.[4]
RESULTS
One study in healthy males aged 18–50 years with androgenetic alopecia (male pattern baldness) found that compared to a baseline of 103 to 106 hairs/cm2, those who applied a 5% solution of minoxidil for 32 weeks increased their non-vellus hair counts by an average of 39 hairs/cm2, in contrast to 5 hairs/cm2 in subjects who received a placebo.[5]
MECHANISM
The mechanism by which minoxidil promotes hair growth is not fully understood. Minoxidil is a potassium channel opener, causing hyperpolarization of cell membranes. Minoxidil is less effective when there is a large area of hair loss. In addition, its effectiveness has largely been demonstrated in younger men (18 to 41 years of age). Minoxidil use is indicated for central (vertex) balding only.[6]
Minoxidil is also a vasodilator[citation needed]. It is speculated that by widening blood vessels and opening potassium channels, it allows more oxygen, blood and nutrients to the follicle. This can also cause follicles in the telogen phase to shed, usually soon to be replaced by new, thicker hairs (in a new anagen phase).
SIDE EFFECTS
As a drug to combat hair loss, the most common side effect is itchy scalp. Alcohol present in topical preparations may dry the scalp, resulting in dandruff.[7] Side effects of oral minoxidil may include swelling of the face and extremities, rapid and irregular heartbeat, lightheadedness, cardiac lesions, and focal necrosis of the papillary muscle and subendocardial areas of the left ventricle.[8] There have been cases of allergic reactions to minoxidil or the non-active ingredient propylene glycol, which is found in some forms of topical Rogaine.
Ironically, hair loss is a common side effect of minoxidil treatment.[9] Manufacturers note that minoxidil-induced hair loss is a common side effect and describe the process as 'shedding'. Although this phenomenon demonstrates that minoxidil is indeed affecting hair follicles, manufacturers offer no guarantee that the new hair loss will be replaced with hair growth.
The speculated reason for this "shedding" is the encouragement of hairs already in the telogen phase to shed early, before often beginning a fresh, healthier anagen phase.
TOXIC EFFECTS
Minoxidil is highly toxic to cats and may cause death.[10][11]
APPLICATION
Minoxidil products involve contact with hair strands, which may cause problems with hair styling since minoxidil must be in an alcohol solution. To keep the minoxidil solution from affecting normal hair styling applications, it can be washed out after at least 40 minutes, although this will decrease the hair regrowth effect. For maximum effect, the solution should be in contact with the scalp for four hours before being washed out. If the solution is not a problem, hair styling devices can be used as soon as the minoxidil solution has dried.
Minoxidil usually needs to be applied regularly (once or twice daily) for hair gained to be maintained. It does not seem capable of reducing DHT or the enzyme responsible for it's accumulation around the hair follicle, 5-alpha reductase, which are the main causes of male pattern baldness in genetically susceptible individuals. Therefore, when treatment is stopped, the DHT already accumulated around the follicle has it's expected effect, and the follicle usually shrinks again and eventually dies.
Minoxidil solutions are sold under many brand names. Many high priced as well as generic brands of minoxidil regrowth solutions exist and do not differ in their active ingredient or concentration (except differing versions within each brand).
REFERENCES
^ www.medicinenet.com/minoxidil-oral/article.htm.
^ "Grant v. Pharmacia & Upjohn Co.". ca10.washburnlaw.edu/cases/2002/12/01-1509.htm. Retrieved 2009-01-17.
^ Olsen EA, Whiting D, Bergfeld W, Miller J, Hordinsky M, Wanser R, Zhang P, Kohut B (2007). "A multicenter, randomized, placebo-controlled, double-blind clinical trial of a novel formulation of 5% minoxidil topical foam versus placebo in the treatment of androgenetic alopecia in men". J Am Acad Dermatol. 57: 767. doi:10.1016/j.jaad.2007.04.012. PMID 17761356.
^ Drug Tariff, retrieved 2009/04/11
^ Rogaine Topical Solution 5%, at Pharmcom, 27 June 2009.
^ Medical Treatments for Balding in Men American Family Physician April 15, 1999
^ "Dandruff and Seborrheic Dermatitis". Medscape.com. www.medscape.com/viewarticle/407641. Retrieved 2009-10-09.
^ "Minoxidil Official FDA information, side effects and uses". Drugs.com. www.drugs.com/pro/minoxidil.html.
^ "Rogaine FAQs". www.rogaine.com/men/faq#question-9.
^ Camille DeClementi; Keith L. Bailey, Spencer C. Goldstein, and Michael Scott Orser (December 2004). "Suspected toxicosis after topical administration of minoxidil in 2 cats". Journal of Veterinary Emergency and Critical Care 14 (4): 287–292. doi:10.1111/j.1476-4431.2004.04014.x.
^ "Minoxidil Warning". ShowCatsOnline.com. www.showcatsonline.com/x/minoxidil.shtml. Retrieved 2007-01-18. "Very small amounts of Minoxidil can result [in] serious problems or death"