Minoxidil (Oral route)
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 .
Antihypertensive, Peripheral Vasodilator
Uses of This Medicine:
Minoxidil belongs to the general class of medicines called antihypertensives. It is used to treat high blood pressure (hypertension).
High blood pressure adds to the workload of the heart and arteries. If it continues for a long time, the heart and arteries may not function properly. This can damage the blood vessels of the brain, heart, and kidneys, resulting in a stroke, heart failure, or kidney failure. High blood pressure may also increase the risk of heart attacks. These problems may be less likely to occur if blood pressure is controlled.
Minoxidil works by relaxing blood vessels so that blood passes through them more easily. This helps to lower blood pressure.
Minoxidil has other effects that could be bothersome for some patients. These include increased hair growth, weight gain, fast heartbeat, and chest pain. Before you take this medicine, be sure that you have discussed the use of it with your doctor.
Minoxidil is being applied to the scalp in liquid form by some balding men to stimulate hair growth. However, improper use of liquids made from minoxidil tablets can result in minoxidil being absorbed into the body, where it may cause unwanted effects on the heart and blood vessels.
Minoxidil is available only with your doctor's prescription.
Before Using This Medicine:
In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:
Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.
Although there is no specific information comparing use of minoxidil in children with use in other age groups, this medicine is not expected to cause different side effects or problems in children than it does in adults.
Elderly patients may be more sensitive to the effects of minoxidil. In addition, minoxidil may reduce tolerance to cold temperatures in elderly patients.
Studies in women suggest that this medication poses minimal risk to the infant when used during breastfeeding.
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your healthcare professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.
Other medical problems—
The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:
- Angina (chest pain)—Minoxidil may make this condition worse
- Heart attack or stroke (recent)—Lowering blood pressure may make problems resulting from heart attack or stroke worse
- Heart or blood vessel disease—Minoxidil can cause fluid buildup, which can cause problems
- Kidney disease—Effects may be increased because of slower removal of minoxidil from the body
- Pheochromocytoma—Minoxidil may cause the tumor to be more active
Proper Use of This Medicine:
In addition to the use of the medicine your doctor has prescribed, treatment for your high blood pressure may include weight control and care in the types of foods you eat, especially foods high in sodium. Your doctor will tell you which of these are most important for you. You should check with your doctor before changing your diet.
Many patients who have high blood pressure will not notice any signs of the problem. In fact, many may feel normal. It is very important that you take your medicine exactly as directed and that you keep your appointments with your doctor even if you feel well.
Remember that minoxidil will not cure your high blood pressure but it does help control it. Therefore, you must continue to take it as directed if you expect to lower your blood pressure and keep it down. You may have to take high blood pressure medicine for the rest of your life . If high blood pressure is not treated, it can cause serious problems such as heart failure, blood vessel disease, stroke, or kidney disease.
To help you remember to take your medicine, try to get into the habit of taking it at the same time each day.
This medicine is usually given together with certain other medicines. If you are using a combination of drugs, make sure that you take each medicine at the proper time and do not mix them. Ask your health care professional to help you plan a way to remember to take your medicines at the right time.
The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.
The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
- For oral dosage forms (tablets):
- Adults and children over 12 years of age: 5 to 40 milligrams taken as a single dose or in divided doses.
- Children up to 12 years of age: 200 micrograms to 1 milligram per kilogram of body weight a day to be taken as a single dose or in divided doses.
If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.
Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.
Keep out of the reach of children.
Do not keep outdated medicine or medicine no longer needed.
Precautions While Using This Medicine:
It is important that your doctor check your progress at regular visits to make sure that this medicine is working properly.
Ask your doctor about checking your pulse rate before and after taking minoxidil. Then, while you are taking this medicine, check your pulse regularly while you are resting. If it increases by 20 beats or more a minute, check with your doctor right away.
While you are taking minoxidil, weigh yourself every day. A weight gain of 2 to 3 pounds (about 1 kg) in an adult is normal and should be lost with continued treatment. However, if you suddenly gain 5 pounds (2 kg) or more (for a child, 2 pounds [1 kg] or more) or if you notice swelling of your feet or lower legs, check with your doctor right away.
Do not take other medicines unless they have been discussed with your doctor. This especially includes over-the-counter (nonprescription) medicines for appetite control, asthma, colds, cough, hay fever, or sinus problems, since they may tend to increase your blood pressure.
Side Effects of This Medicine:
- More common
- Fast or irregular heartbeat
- weight gain (rapid) of more than 5 pounds (2 pounds in children)
- Less common
- Chest pain
- shortness of breath
- More common
- flushing or redness of skin
- swelling of feet or lower legs
- Less common
- Numbness or tingling of hands, feet, or face
- Skin rash and itching
Along with its needed effects, a medicine 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:
Check with your doctor as soon as possible if any of the following side effects occur:
- More common
- Increase in hair growth, usually on face, arms, and back
- Less common or rare
- Breast tenderness in males and females
Some side effects 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:
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.
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Last Updated: 6/2/2022