Minoxidil is an antihypertensive medication that is used as a tablet to treat severe high blood pressure, and serendipitously has been found to help baldness when used as a lotion.
It should be used in pregnancy and breastfeeding only if medically necessary, and should not be used for mild high blood pressure or if the patient has recently had a heart attack. Fluid intake must be controlled carefully and it may be necessary to check the heart with regular cardiographs (ECG). Use of the lotion should only be on the scalp.
Common side effects include excess hair growth on face and scalp, darkening and thickening of fine body hair, weight gain, fluid retention, increased heart rate, and less commonly low blood pressure, breast tenderness, rash, nausea and diarrhoea. The lotion reacts adversely with steroid creams and acne preparations. The success in baldness varies greatly between patients, and long-term use is required.