Minoxidil for high blood pressure

  • Minoxidil is used to control high blood pressure. It will be prescribed by a specialist.
  • Treatment with minoxidil is usually long-term.
  • Minoxidil may make you heart beat more quickly and cause your body to keep more fluid than normal. You will be prescribed other medicines to help control this.
Type of medicine Vasodilator antihypertensive medicine
Used for The treatment of very high blood pressure
Also called Loniten®
Available as Tablets

Most people with high blood pressure do not feel unwell, but it is important that your high blood pressure is treated even if you feel fine. If left untreated, high blood pressure is a risk factor that can increase your chance of developing heart disease, a stroke, and other serious conditions. Minoxidil will be prescribed for you if other medicines have not been sufficient to control your high blood pressure. It will be prescribed for you by a specialist.

Minoxidil works by relaxing the muscles in the walls of your blood vessels. This means that your blood vessels widen, which reduces your blood pressure and allows blood and oxygen to circulate more freely around your body. You will also be prescribed other medicines to take alongside minoxidil. These are to help regulate the amount of water and salt in your body, and also to help control your heart rate because these can be increased by taking minoxidil.

Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start taking minoxidil it is important that your doctor or pharmacist knows:

  • If you have kidney problems.
  • If you have angina chest pain, or if you have recently had a heart attack.
  • If you have a rare inherited blood disorder called porphyria.
  • If you have been told you have a tumour on your adrenal glands (this is known as phaeochromocytoma).
  • If you are taking or using any other medicines. This includes any medicines you are taking which are available to buy without a prescription, such as herbal and complementary medicines.
  • If you have ever had an allergic reaction to any medicine.
  • If you are pregnant or breast-feeding. Minoxidil is generally unsuitable for women; however, if it has been prescribed for you and you are pregnant or breast-feeding, you must make sure your doctor knows this.
  • Before you start this treatment, read the manufacturer's printed information leaflet from inside your pack. The leaflet will give you more information about minoxidil, and a full list of possible side-effects from taking it.
  • Take minoxidil exactly as your doctor has told you. Your doctor or pharmacist will tell you how many tablets to take and when to take them, and your dose will also be on the label of the pack to remind you. Swallow the tablets with a drink of water - do not break, crush or chew the tablets.
  • When you first start taking minoxidil, your doctor may give you a small dose and then gradually increase it. This allows your doctor to make sure that you have the dose that helps your condition and avoids any unwanted symptoms.
  • It is usual to take one or two doses of minoxidil each day. Try to take your doses at the same times each day, as this will help you to remember to take them.
  • If you do forget to take a dose, take it as soon as you remember (unless it is nearly time for your next dose, in which case leave out the missed dose). Do not take two doses together to make up for a forgotten dose.
  • Try to keep your regular appointments with your doctor. This is so your doctor can check on your progress.
  • Drinking alcohol while you are on minoxidil may increase the chance that you experience side-effects and is not recommended.
  • If you buy any medicines, check with a pharmacist that they are suitable for you to take. This is because some medicines (including some anti-inflammatory painkillers) may interfere with minoxidil.
  • Your doctor will discuss with you the possibility of unwanted side-effects of treatment, such as your fine body hair becoming darker and thicker. This may be noticed about a month after starting minoxidil.
  • Minoxidil is generally unsuitable for women, but if it has been prescribed for you and you could get pregnant, you should ask your doctor about what methods of contraception are suitable for you. This is because you should avoid becoming pregnant while you are on minoxidil.
  • Treatment with minoxidil is usually long-term unless you experience an adverse effect. Continue to take the tablets unless you are advised otherwise.
  • If you are having an operation or dental treatment, tell the person carrying out the treatment that you are taking minoxidil. This is because some anaesthetics can affect your blood pressure.
  • Your doctor will advise you on what lifestyle changes you can make to help your condition. These may include losing weight if you are overweight, taking regular physical activity, eating a healthy diet, cutting back if you drink a lot of alcohol, stopping smoking, and reducing the amount of salt in your meals and caffeine in your drinks. It is important that you follow any advice you have been given.

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. These usually improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following side-effects continue or become troublesome.

Common minoxidil side-effects What can I do if I experience this?
Your body may retain more fluid than normal If you notice you are putting on weight or if your ankles or feet become swollen, let your doctor know
Changes in your hair colour, thickness or texture If this becomes troublesome, speak with your doctor
A fast heartbeat, and other heart rhythm changes If you are concerned about this, speak with your doctor

If you experience any other symptoms which you think may be due to this medicine, discuss them with your doctor or pharmacist.

  • Keep all medicines out of the reach and sight of children.
  • Store in a cool, dry place, away from direct heat and light.
  • Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine, go to the accident and emergency department of your local hospital. Take the container with you, even if it is empty.
  • This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.
  • Never keep-out-of date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.
  • If you have any questions about this medicine ask your pharmacist.

Further reading & references

  • British National Formulary; 63rd Edition (Mar 2012) British Medical Association and Royal Pharmaceutical Society of Great Britain, London
  • Manufacturer's PIL, LonitenĀ® Tablets 2.5 mg, 5 mg and 10 mg; Manufacturer's PIL, LonitenĀ® Tablets 2.5 mg, 5 mg and 10 mg, Pharmacia Limited, electronic Medicines Compendium. Dated February 2012.
Original Author: Helen Allen Current Version: Peer Reviewer: Dr Adrian Bonsall
Last Checked: 19/07/2012 Document ID: 3365  Version: 23 © EMIS

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.

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