Minoxidil is a vasodilator and originally was exclusively used as an oral drug (Loniten®) to treat high blood pressure. It was, however, discovered to have the interesting side effect of hair growth and reversing baldness. In the 1980s, UpJohn Corporation produced a topical solution that contained 2% minoxidil to be used to treat baldness and hair loss, under the brand name Rogaine. It is unknown how the drug stimulates hair growth.
Minoxidil was spoofed in the episode of The Simpsons entitled Simpson and Delilah, in which Homer uses the ‘Dimoxinil’ hair growth drug and becomes a high-flying executive after regaining his hair.
Side effects
As a drug to combat hair loss, the most common side effect is itchy scalp.
There have been cases of allergic reactions to minoxidil or the non-active ingredient propylene glycol which is found in some forms of the topical version, such as Rogaine. Large amounts of minoxidil can cause hypotension, and it has been found that using petroleum jelly or tretinoin on the scalp with minoxidil can cause too much of the drug absorption by the scalp, as can using the drug on sunburned scalps.
If a person uses minoxidil to stop hair loss for a length of time and then stops taking the drug, hair loss will occur again.
Other side effects, although not as common, include:
- acne on the area where it is being used as a topical solution
- headaches and/or lightheadedness
- hypertrichosis (37 %)
- impotence
- very low blood pressure
- irregular or fast heart beat
- flushing of the skin
- blurred vision
- numbness or tingling in the hands, feet, or face
- decrease in sexual desire
- chest pain
- rapid weight gain
- swelling of the lower legs, hands, feet, or face
All the side effects in the above list except for acne may be an indicator that too much of the drug is being used.
It has also been found that the drug can be passed from a mother to a child via breast milk.
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