Minoxidil Side Effects
Medically reviewed by Drugs.com. Last updated on Nov 20, 2020.
For the Consumer
Applies to minoxidil: oral tablet
Oral route (Tablet)
Minoxidil can cause pericardial effusion, occasionally progressing to tamponade, and angina pectoris may be exacerbated. Minoxidil should be reserved for hypertensive patients who do not respond adequately to maximum therapeutic doses of a diuretic and two other antihypertensive agents. Minoxidil must be administered under close supervision, usually concomitantly with therapeutic doses of a beta-adrenergic blocking agent to prevent tachycardia and increased myocardial workload. It must also usually be given with a diuretic, frequently one acting in the ascending limb of the loop of Henle, to prevent serious fluid accumulation. Patients with malignant hypertension and those already receiving guanethidine should be hospitalized when minoxidil is first administered so that they can be monitored to avoid too rapid, or large orthostatic, decreases in blood pressure.
Side effects requiring immediate medical attention
Along with its needed effects, minoxidil may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur while taking minoxidil:
- Fast or irregular heartbeat
- weight gain (rapid) of more than 5 pounds (2 pounds in children)
- Chest pain
- shortness of breath
Check with your doctor as soon as possible if any of the following side effects occur while taking minoxidil:
- flushing or redness of skin
- swelling of feet or lower legs
- Numbness or tingling of hands, feet, or face
- Skin rash and itching
Side effects not requiring immediate medical attention
Some side effects of minoxidil may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.
Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
- Increase in hair growth, usually on face, arms, and back
Less common or rare
- Breast tenderness in males and females
This medicine causes a temporary increase in hair growth in most people. Hair may grow longer and darker in both men and women. This may first be noticed on the face several weeks after you start taking minoxidil. Later, new hair growth may be noticed on the back, arms, legs, and scalp. Talk to your doctor about shaving or using a hair remover during this time. After treatment with minoxidil has ended, the hair will stop growing, although it may take several months for the new hair growth to go away.
For Healthcare Professionals
Applies to minoxidil: compounding powder, oral tablet
Most patients receiving have experienced a decrease of preexisting adverse medical events attributable to their disease or previous therapy. The most frequently reported side effects were hypertrichosis, tachycardia, pericarditis, and an abnormal ECG.[Ref]
Very common (10% or more): ECG abnormal (up to 60%), tachycardia, pericarditis
Common (1% to 10%): Pericardial effusion, tamponade
Very common (10% or more): Hypertrichosis (up to 80%), hair color changed
Rare (less than 0.1%): Stevens-Johnson syndrome, dermatitis bullous, rash
Elongation, thickening, and enhanced pigmentation of fine body hair has been reported in about 80% of patients. This usually develops within 3 to 6 weeks after beginning therapy and is first noticed on the temples, between the eyebrows, between the hairline and the eyebrows, or in the sideburn area of the upper lateral cheek, and eventually extending to the back, arms, legs, and scalp. Upon discontinuation of this drug, new hair growth stops, however, 1 to 6 months may be required for restoration to pretreatment appearance. Endocrine abnormalities have not been found to explain the abnormal hair growth.[Ref]
Common (1% to 10%): Gastrointestinal disorder
Rare (less than 0.1%): Leukopenia, thrombocytopenia
Frequency not reported: Hematocrit decreased, hemoglobin decreased, erythrocyte count decreased
Uncommon (0.1% to 1%): Breast tenderness[Ref]
Uncommon (0.1% to 1%): Pleural effusion
Common (1% to 10%): Edema
Frequency not reported: Peripheral edema, weight gain, blood creatinine increased, blood urea increased, alkaline phosphatase increased[Ref]
1. Cerner Multum, Inc. "Australian Product Information." O 0
2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
3. "Product Information. Loniten (minoxidil)." Pharmacia and Upjohn, Kalamazoo, MI.
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Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Some side effects may not be reported. You may report them to the FDA.