Minoxidil, the generic name for Rogaine, is a medication that was originally used in pill form for treating high blood pressure because of its ability to dilate, or widen, blood vessels. When used for this purpose, one of minoxidil’s side effects was noted to be excessive hair growth. Rogaine became the first medication approved by the Food and Drug Administration (FDA) to treat hair loss, although the exact way that it accomplishes this is still unknown. In women, Rogaine is applied topically to the scalp in the area of hair loss, either as a 2 percent solution or a 5 percent foam. Rogaine is generally safe, but there are a few possible serious side effects.
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Blood Pressure and Heart Rate
Rogaine may potentially lower the blood pressure. This occurs when the medication is absorbed through the skin and into the bloodstream. However, significant changes in blood pressure are rare, as less than 1 percent of Rogaine is absorbed, according to a review article published in the May to June 2013 issue of “Skin Therapy Letter.”
A fast heart rate or palpitations may sometimes occur with Rogaine use. They were observed in 1.8 percent of women receiving Rogaine foam and 3.5 percent of women receiving Rogaine solution in a study published in the “Journal of the American Academy of Dermatology” in December 2011.
Like any medication, Rogaine may cause an allergic reaction. Fortunately, these reactions are usually mild and localized to the skin. They are generally a form of contact dermatitis, which is a type of allergic reaction characterized by a rash, itching and inflammation in the area of application. Most instances of contact dermatitis are caused by propylene glycol -- an ingredient in the Rogaine solution -- and not by minoxidil itself, according to the May to June 2013 review article in “Skin Therapy Letter.” Rogaine foam does not contain propylene glycol. Very rarely, a severe allergic reaction may occur, producing a generalized rash or redness, shortness of breath, swelling or decreased level of consciousness.
Pregnancy, Breastfeeding and Children
The FDA advises against using Rogaine while pregnant or breastfeeding. Rogaine is a Pregnancy Category C drug, which means that there is not enough scientific evidence regarding whether it will have an effect on the unborn child -- thus, the possibility of a harmful effect cannot be ruled out. It is unclear whether Rogaine can be absorbed in sufficient amounts to enter the breast milk, but minoxidil taken in pill form has been detected in breast milk.
Rogaine is not approved by the FDA for use as an over-the-counter medication in anyone under the age of 18 years. It should only be used in these age groups under the direction of a physician.
Warnings and Precautions
If you are considering using Rogaine, see your doctor to determine whether it is appropriate and safe for your particular situation. Hair loss may be caused by conditions that require other treatment, such scalp infections or thyroid disease. If you have heart disease or are taking certain medications, your doctor may advise against Rogaine, as you may be more likely to develop a significant decrease in blood pressure.
Avoid being near a fire or flame and do not smoke while applying Rogaine or immediately afterward. Both Rogaine solution and Rogaine foam contain flammable ingredients that can catch on fire. Stop using the medication if you develop any skin reaction. See your doctor if you feel dizzy or lightheaded, especially when standing, as this may indicate a low blood pressure. Seek immediate medical attention if you have symptoms of a severe allergic reaction.
Reviewed and revised by: Mary D. Daley, MD