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Drug Info

Minoxidil side effects and how to avoid them

Cropped SingleCare logo By | May 14, 2020
Medically reviewed by Karen Berger, Pharm.D.

You’ve likely heard of minoxidil, commonly known by its brand name: Rogaine. This topical product is available over-the-counter to treat male pattern baldness. Rogaine contains 2% to 5% minoxidil and is often used to treat baldness or hair loss in both men and women.

What you might not know is that minoxidil can also treat high blood pressure (hypertension). In the tablet form, it’s a vasodilator medication that helps the blood vessels expand to increase the blood flow throughout the body. Oral minoxidil is only available with a prescription. Loniten, brand-name minoxidil, is no longer sold; only general minoxidil is currently available for high blood pressure.

For many people, minoxidil restores confidence through hair regrowth. Or, it normalizes stubbornly high blood pressure levels, but the reward comes with possible risks.

Common side effects of minoxidil

The most common side effect of topical minoxidil is application site pain, such as dryness, itching, stinging, scaling, flaking, or redness. Don’t use Rogaine if your scalp is already irritated, or you have a rash or sunburn on your scalp. Additionally, changes in texture or color of body hair may occur. Some individuals experience very little or no adverse reaction to topical minoxidil, while others are more sensitive.

Oral minoxidil side effects include headache, nausea, or vomiting.

These side effects may be temporary and naturally resolve once your body adjusts to the medication. Most of the side effects of minoxidil go away when you stop using the product. 

Serious side effects of minoxidil

Minoxidil can cause severe or long-term side effects. It’s rare, but your skin can absorb minoxidil. Stop using minoxidil if you experience any of the following side effects:

  • Dizziness
  • Flushing 
  • Irregular heartbeat
  • Fainting
  • Fatigue
  • Difficulty breathing when lying down
  • Swelling in hands or feet
  • Unusual (rapid) weight gain
  • Unwanted body or facial hair growth 

As a vasodilator, minoxidil causes an increase in blood supply, which can also increase your heart rate. Healthcare providers may advise people with pre-existing heart conditions against using products containing minoxidil because it can increase heart rate and cause chest pains, signaling heart failure. If you have heart problems, consult your healthcare provider before using minoxidil.

Minoxidil warnings

The Food and Drug Administration (FDA) assigned minoxidil a black box warning for serious side effects. This alerts patients and healthcare professionals about potential harm when using this drug. Consult your healthcare provider before taking new medications if you have kidney disease, heart disease, or a pre-existing heart condition. In these cases, using minoxidil may not be the right choice for you. 

Individuals younger than 18 years old should not use minoxidil products like Rogaine. Elderly individuals who use minoxidil may experience increased sensitivity to cold temperatures.

Minoxidil topical solution should present a low-risk factor to breastfeeding infants. However, pregnant or lactating women should seek professional medical advice before using topical minoxidil products like Rogaine. A minute amount of minoxidil solution could pass through the mother’s breast milk to the infant. As for oral minoxidil taken for high blood pressure, consult your healthcare provider if you are expecting, as it has not been tested in pregnant women. Oral minoxidil should not be used if you are breastfeeding. 

Minoxidil interactions

Topical minoxidil (generic Rogaine) has no known drug interactions. However, you should avoid using other skincare products—especially those that contain alcohol—in the same area you apply minoxidil unless approved by a healthcare provider. You can use hair color, relaxers, and perms, but wash the scalp before applying the hair treatment. Also, you should not use minoxidil 24 hours before or after the hair treatment. 

Oral minoxidil (generic Loniten) can interact with the blood pressure medication called guanethidine and cause orthostatic hypotension. This type of low blood pressure happens when standing up after sitting or lying down. Discontinue guanethidine before taking minoxidil. Your healthcare provider will advise you when to stop guanethidine and when to begin minoxidil. 

Can you drink alcohol while using minoxidil?

Oral minoxidil can have an adverse drug interaction with alcohol, causing a decrease in blood pressure. But topical minoxidil does not significantly react with alcohol use. However, alcohol can dry out the skin, which could irritate your scalp when using topical minoxidil products.

Should I take finasteride when using minoxidil?

Studies indicate that taking finasteride while also using minoxidil is safe. Originally designed to treat enlarged prostate (benign prostatic hyperplasia, or BPH), finasteride is an oral prescription medication that can boost hair growth. Brand names of finasteride include Proscar (finasteride 5 mg) and Propecia (finasteride 1 mg). Proscar is only indicated for male BPH but is sometimes prescribed off-label for hair growth. Propecia treats male pattern hair loss. 

Neither Proscar nor Propecia is indicated for use in women, although sometimes the medications may be prescribed off-label for women who are past childbearing age. It is important to note that finasteride can cause fetal abnormalities in a male fetus. Women who are pregnant or of childbearing age should not take Proscar or Propecia and should avoid handling crushed or broken tablets.

Some finasteride products may affect sperm count, while minoxidil does not.

How to avoid topical minoxidil side effects 

To avoid Rogaine side effects, use it as directed. Hair growth can be a naturally slow process. Visible results may be noticeable in eight weeks but may also take up to four months to see a difference in hair growth. Hair loss (shedding) may even occur at first as the new hair pushes out the older hairs, but if hair loss persists, discontinue the use of the product. 

Each product has a specific set of instructions for that formula. Most people apply the medication twice a day; some require a minimum of a one-hour application, though it can even be used overnight. If you miss a dose, apply the missed dose as soon as possible. If the application time for the next dose is near, wait, and apply the medicine then. Do not double doses.

Rogaine has a shelf life of two to three years, depending on the formula. Keep the product at room temperature conditions of 68 to 77 degrees Fahrenheit. High temperatures can cause the product to lose effectiveness. Also, the product could be flammable and should be discarded after the expiration date.

How to avoid oral minoxidil side effects

Oral minoxidil is usually prescribed with both a diuretic and a beta-blocker. Swelling is one of the potential adverse effects of minoxidil, but a prescription diuretic pill can help reduce unwanted fluids. Your doctor will most likely prescribe these medications together. Your hands, feet, ankles, stomach, or face can swell as a result of salt and water retention caused when taking minoxidil. Water retention may cause a sudden weight gain of five pounds or more. Excess fluids in the body can be damaging and lead to congestive heart failure if treated incorrectly. 

In addition to a diuretic pill, your healthcare provider will likely also prescribe a beta-adrenergic blocking medicine. Because minoxidil can increase one’s heart rate, a beta blocker can lower blood pressure by blocking epinephrine (adrenaline). Seek medical attention immediately if you are taking minoxidil and are experiencing chest pains or difficulty breathing.

Does minoxidil really work?

Oral minoxidil is particularly effective for hypertensive patients who have tried other drug regimens (maximum dose of a diuretic plus two other antihypertensive medications) that were unsuccessful. Taking minoxidil with a diuretic and beta blocker can limit minoxidil side effects. Its benefits usually outweigh its risks.

Topical minoxidil used for hair growth is clinically proven to work. Blood vessels in the scalp open, allowing nutrients to get to the hair follicles. Minoxidil works for hereditary hair loss, which is hair loss due to heredity, hormones, and age.  Minoxidil may not be sufficient for certain types of hair loss such as hair loss from an autoimmune disorder like lupus, or hair loss from chemotherapy, pregnancy, or menopause. 

Many people ask if Rogaine is a dihydrotestosterone (DHT) blocker. DHT is a hormone associated with male pattern baldness, but Rogaine does not affect DHT. Rogaine works to rejuvenate hair follicle health so new hair can grow.

Rogaine is most effective on long-term hair loss versus sudden hair loss. While hair growth is noticeable within four months of using the product, the benefits of this product will cease when you stop using it. You must continually use the product to maintain hair regrowth.

“Most people experience hair shedding when starting and stopping minoxidil and with inconsistent use,” says Susan Bard, MD, a board-certified dermatologist of Manhattan Specialty Care. “It is recommended that patients not abruptly start and restart minoxidil and to use it consistently to prevent shedding.”