Quinine for leg cramps

  • The usual dose for leg cramps is one tablet at bedtime.
  • Quinine is present in drinks such as tonic water and bitter lemon - try to avoid these while you are on quinine.
  • Contact a doctor immediately if anyone takes these tablets by accident, or if you take too many tablets.
Type of medicineAntimalarial
Used forTreatment of night-time leg cramps
Also calledQuinine bisulphate, quinine dihydrochloride, quinine sulphate
Available asTablets

Quinine is used for leg cramps as a last resort and only if the cramps regularly disrupt your sleep or are very painful. Other treatments, such as stretching exercises and massaging the affected muscle, will be recommended first.

Quinine is likely to reduce the number and/or severity of your leg cramps, but it may not stop them altogether. When quinine is first prescribed it will be done on a trial basis for a few weeks, as it may take this amount of time for you to start to feel the benefit. You can assess how well quinine works for you, by keeping a sleep and cramp diary before and after the start of treatment. Quinine can sometimes cause side-effects (some of which may be serious) so you should also check for any unwanted effects it is having on you. If quinine helps you, then you may be advised to continue with it for a few months. You should, however, consider stopping quinine every three months or so. This is because, in some people, the cramps go away and so the treatment may no longer be needed.

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 quinine it is important that your doctor or pharmacist knows:

  • If you are pregnant, trying for a baby or breast-feeding.
  • If you have any problems with your eyes, or with your hearing.
  • If you have any problems with your kidneys, liver or heart.
  • If you have blood in your urine.
  • If you have myasthenia gravis (a condition causing muscle weakness).
  • If you have glucose 6-phosphate dehydrogenase deficiency (this is an inherited disorder).
  • If you are taking other medicines, including those available to buy without a prescription, herbal and complementary medicines.
  • If you have ever had an allergic reaction to any medicine, or if you have had a bad reaction to quinine in tonic water or any other soft drink.
  • Before you start this treatment, read the manufacturer's printed information leaflet from inside your pack. The leaflet will give you more information about quinine, and a full list of possible side-effects from taking it.
  • Take quinine exactly as your doctor has told you. The usual dose is one tablet at bedtime. Your dose will also be on the label of the pack you have been given.
  • If you forget to take a dose, do not worry, just skip the missed dose and take your next dose the following evening. 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.
  • Your doctor will have discussed with you the possibility of unwanted side-effects of treatment with quinine. Let your doctor know as soon as possible if you experience any of the following: impaired hearing, ringing noises in your ear, headaches, feeling sick, or problems with your eyesight.
  • Quinine is present in drinks such as tonic water and bitter lemon. It is probably best to avoid these while you are on quinine.
  • Never take more than the prescribed dose. Taking too much quinine can cause serious problems. Also, quinine is dangerous if it is taken by a child. If you suspect that someone has taken an overdose of quinine, contact your doctor or go to the accident and emergency department of your local hospital straightaway. Take the container with you, even if it is empty. This is so the doctor knows what has been taken.
  • If you buy any medicines, check with a pharmacist that they are suitable to take with your other medicines. This is because some medicines may interfere with quinine.
  • If you have diabetes you may need to check your blood glucose more frequently, as these tablets may affect the levels of sugar in your blood. Your doctor will be able to advise you about this.

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. Side-effects are uncommon when quinine is used to treat leg cramps; however, serious side-effects do sometimes occur. Speak with your doctor or pharmacist if any of the following side-effects occur.

Possible quinine side-effectsWhat can I do if I experience this?
Hearing problems, vertigo (a feeling of spinning), headache, feeling or being sick, abdominal pain, diarrhoea, difficulties seeing, feeling confusedTell your doctor about any of these as soon as possible
Hot and flushed skin, rashes, muscle weakness, increased sensitivity to lightIf any of these become troublesome, let your doctor know

Important: your doctor will have discussed with you the possibility of unwanted side-effects of treatment with quinine that you must let your doctor know about. Stop taking quinine and contact your doctor straightaway if you experience any of the following:

  • Any difficulty breathing, or any swelling around your mouth or face. These may be signs of an allergic reaction to quinine.
  • An unexplained bleeding or unusual bruising. These may be signs of a serious blood disorder and your doctor will want to check for this.
  • Keep all medicines out of the reach and sight of children.
  • Store in a cool, dry place, away from direct heat and light.
  • If you are having an operation or dental treatment, tell the person carrying out the treatment which medicines you are taking.
  • 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, Quinine Sulphate Tablets 300 mg; Manufacturer's PIL, Quinine Sulphate Tablets 300 mg, Actavis UK Ltd, The electronic Medicines Compendium. Dated May 2010.

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.

Original Author:
Helen Allen
Current Version:
Peer Reviewer:
Dr John Cox
Document ID:
3241 (v25)
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