Minoxidil Side Effects

Brand Names: Loniten

Please note - some side effects for Minoxidil may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA at http://www.fda.gov/medwatch/ or 1-800-FDA-1088 (1-800-332-1088).

Side Effects of Minoxidil - for the Consumer

Minoxidil

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Minoxidil:

Changes in body hair; excessive hair growth; mild weight gain; nausea; vomiting.

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); changes in hearing or vision; difficulty breathing; excessive, sudden weight gain; fainting; lightheadedness; increased chest, arm, or shoulder pain; increased heart rate; pounding heartbeat; swelling.

Minoxidil Foam (For Men)

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Minoxidil Foam (For Men):

Changes in hair color or texture.

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); chest pain; dizziness; fainting; fast heartbeat; redness or irritation of the scalp; sudden, unexplained weight gain; swelling of the hands or feet; unwanted facial hair growth.

Minoxidil Solution

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Minoxidil Solution:

Burning or irritation of the eye; itching; redness or irritation at the treated area; unwanted hair growth elsewhere on the body.

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); chest pain; dizziness; fainting; fast heartbeat; sudden, unexplained weight gain; swollen hands or feet.

Minoxidil Side Effects - for the Professional

Minoxidil

1. Salt and Water Retention—Temporary edema developed in 7% of patients who were not edematous at the start of therapy.

2. Pericarditis, Pericardial Effusion, and Tamponade.

3. Dermatologic—Hypertrichosis—Elongation, thickening, and enhanced pigmentation of fine body hair are seen in about 80% of patients taking Minoxidil tablets. This develops within 3 to 6 weeks after starting therapy. It is usually first noticed on the temples, between the eyebrows, between the hairline and the eyebrows, or in the side-burn area of the upper lateral cheek, later extending to the back, arms, legs, and scalp. Upon discontinuation of Minoxidil, new hair growth stops, but 1 to 6 months may be required for restoration to pretreatment appearance. No endocrine abnormalities have been found to explain the abnormal hair growth; thus, it is hypertrichosis without virilism. Hair growth is especially disturbing to children and women and such patients should be thoroughly informed about this effect before therapy with Minoxidil is begun.

Allergic—Rashes have been reported, including rare reports of bullous eruptions, and Stevens-Johnson Syndrome.

4. Hematologic—Thrombocytopenia and leukopenia (WBC<3000/mm3) have rarely been reported.

5. Gastrointestinal—Nausea and/or vomiting has been reported. In clinical trials the incidence of nausea and vomiting associated with the underlying disease has shown a decrease from pretrial levels.

6. Miscellaneous—Breast tenderness—This developed in less than 1% of patients.

7. Altered Laboratory Findings—(a) ECG changes—Changes in direction and magnitude of the ECG T-waves occur in approximately 60% of patients treated with Minoxidil. In rare instances a large negative amplitude of the T-wave may encroach upon the S-T segment, but the S-T segment is not independently altered. These changes usually disappear with continuance of treatment and revert to the pretreatment state if Minoxidil is discontinued. No symptoms have been associated with these changes, nor have there been alterations in blood cell counts or in plasma enzyme concentrations that would suggest myocardial damage. Long-term treatment of patients manifesting such changes has provided no evidence of deteriorating cardiac function. At present the changes appear to be nonspecific and without identifiable clinical significance. (b)—Effects of hemodilution–hematocrit, hemoglobin and erythrocyte count usually fall about 7% initially and then recover to pretreatment levels. (c) Other—Alkaline phosphatase increased varyingly without other evidence of liver or bone abnormality. Serum creatinine increased an average of 6% and BUN slightly more, but later declined to pretreatment levels.

Side Effects by Body System

General

Minoxidil is usually administered with a beta-blocker to counteract the increased cardiac output and cardiac work associated with profound minoxidil-induced vasodilation and with a loop diuretic to counteract the sodium and water retaining properties of minoxidil.

Cardiovascular

Cardiovascular side effects are related to peripheral vasodilation and sodium and water retention, and include hypotension, sinus tachycardia, provocation of angina, edema, and weight gain. Edema is expected without concomitant use of a diuretic agent.

Pericardial effusions occur in up to 5% of patients and may be more likely in patients with renal insufficiency. Reversible, nonspecific ST-T wave electrocardiographic changes occur in 30% to 90% of patients.

The hypotensive effect of minoxidil may last for days after drug discontinuation.

The mechanism of minoxidil-associated angina is not known. Theories include a coronary "steal" phenomenon secondary to coronary vasodilation, resulting in relative ischemia to hypoperfused areas of myocardium and increased cardiac work secondary to minoxidil-induced reflex tachycardia.

Nonspecific ST-T wave changes are not necessarily associated with cardiac disease.

The incidence of pericardial effusion in minoxidil-treated uremic patients is greater than that expected in non-treated uremic patients. Tamponade is reported in up to 23% of minoxidil-associated pericardial effusions, which has been fatal in rare cases.

Rare cases of pulmonary hypertension have been associated with minoxidil. Pulmonary hypertension is thought to be due to a minoxidil-induced increase in cardiac output and in pulmonary blood flow.

Hemorrhagic and degenerative lesions of the right atrium and focal necrosis of the left ventricular papillary muscle have been described in dog studies, but not in monkeys. No data are available in humans.

Dermatologic

Hypertrichosis usually begins at the temples, forehead, and between the eyebrows, but may involve the trunk, extremities, and scalp. Some studies have shown hypertrichosis to occur at lower doses in females, although it may be that females were more distressed by this side effect, and presented these findings earlier than men did.

Dermatologic side effects are common. Hypertrichosis occurs in 30% to 80% of patients within the first 3 to 6 weeks of therapy. It usually presents as elongated and hyperpigmented new hair. Hypertrichosis is reversible.

Hypersensitivity

Hypersensitivity reactions such as contact dermatitis, desquamative and bullous rashes, and Stevens-Johnson syndrome have been reported in less than 1% of patients.

Gastrointestinal

Gastrointestinal side effects are uncommon and include nausea and vomiting.

Hematologic

Hematologic side effects, such as decreased hematocrit and hemoglobin, are usually related to dilution from minoxidil-induced sodium and water retention.

A case of thrombocytopenia associated with minoxidil, which recurred upon rechallenge, has been reported.

Nervous system

A case of bilateral optic neuritis, followed by atrophy and vision loss, was associated with minoxidil, despite the fact that the patient was taking other medications as well.

Nervous system side effects are usually limited to headache in approximately 6% and dizziness in approximately 2% of patients. Rare cases of general fatigue have been reported.

Immunologic

Immunologic side effects are extremely rare.

A case of a lupus syndrome associated with the development of a speckled ANA pattern has been associated with minoxidil. The patient had previously taken hydralazine, but did not test positive for ANA until after minoxidil was substituted for hydralazine.

Endocrine

Endocrine side effects include at least one case of pseudoacromegaly. A case of pseudoacromegaly which resulted from long-term (10 years) use of minoxidil (50 mg/day) has been reported.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date, and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This information does not endorse drugs, diagnose patients, or recommend therapy. This drug information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug of drug combination is safe, effective, or appropriate for any given patient. Drugs.com does not assume any responsibility for any aspect of healthcare administered with the aid of information provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse, or pharmacist.