Propranolol: uses, doses, side effects and cautions

The NHS lists high blood pressure, irregular heartbeats including atrial fibrillation, prevention of further heart problems after a heart attack, angina, anxiety symptoms, migraine prevention and thyrotoxicosis as uses. It is a beta blocker and available only on prescription.

The NHS explains that it slows the heart rate and makes it easier for the heart to pump blood around the body. For anxiety, that is why it can ease physical symptoms such as sweating and trembling; it does not treat the worry itself.

Standard tablets and liquid are quick-release and taken several times a day; slow-release capsules are taken once daily. The NHS gives these typical adult starting figures, and says doses are usually lower for people over 65 or with kidney or liver problems.

Swallow tablets and capsules whole with water. Measure liquid with the syringe or spoon supplied. Propranolol does not usually upset the stomach, so food does not matter. The first doses can cause dizziness, and bedtime dosing is suggested.

Duration depends on the reason: heart conditions may need lifelong treatment, anxiety is generally short term, and migraine prevention can last several months to years. If you miss a dose, take it when you remember unless the next is nearly due; never double up. After an overdose with slow heart rate, breathing problems, dizziness, seizures or chest pain, call 999 or go to A&E.

Talk to your doctor before stopping. The NHS says doses are usually reduced gradually over one to two weeks.

Tell the prescriber if you have had an allergic reaction to propranolol, have low blood pressure, a slow heart rate, worsening heart failure, a history of depression or self-harm thoughts, diabetes, liver or kidney problems, severe circulation problems in the limbs such as Raynaud phenomenon, metabolic acidosis, lung disease or asthma, or an adrenal gland tumour called phaeochromocytoma. Pregnancy, planning pregnancy and breastfeeding should also be raised.

Headaches, tiredness, dizziness, weakness, cold hands and feet, sickness, diarrhoea and sleep problems with nightmares are the common ones. The NHS says they are usually mild and short lived. For cold fingers, warm running water and massage can help, and smoking and caffeine make it worse. For sleep problems, avoid large evening meals, alcohol, tea and coffee.

Easy bruising, or shortness of breath with a worsening cough, swollen ankles or an irregular heartbeat, should be reported promptly to a doctor or NHS 111. Call 999 for new or worsening chest pain or signs of a serious allergic reaction.

Named interacting medicines include amiodarone, digoxin and flecainide, other blood pressure medicines, nitrates, antidepressants, baclofen, tamsulosin, levodopa, asthma and COPD medicines, insulin and diabetes medicines, nasal decongestants and cold remedies, ephedrine, noradrenaline and adrenaline, NSAIDs such as ibuprofen, diclofenac and naproxen, and rizatriptan. There is little information on herbal remedies.

Avoid alcohol if you feel dizzy or weak, and do not drive until these have passed.

You can take propranolol during pregnancy, but it can sometimes affect the baby's growth, and the NHS recommends extra growth scans from around week 32. Propranolol passes into breast milk in tiny amounts and has not been known to cause side effects in breastfed babies. There is no evidence it affects fertility. Report suspected side effects via the Yellow Card scheme.