Nortriptyline: uses, side effects and cautions

Nortriptyline is a tricyclic antidepressant. The NHS says it is used for nerve pain and for depression. For depression it increases serotonin in the brain to improve mood. For pain it changes how nerves process pain signals.

Most adults can take it, and teenagers aged 12 to 17 can take it for depression.

The NHS gives two timelines. Nerve pain relief tends to start after about a week, and sleep may improve within days. Depression takes longer: a couple of weeks for early signs, and 4 to 6 weeks to work fully. It advises allowing at least six weeks before deciding whether it is helping.

If it is not helping or the side effects are bothersome after six weeks, go back to the prescriber to talk about alternatives.

Nortriptyline comes as tablets in 10 mg, 25 mg and 50 mg strengths, and as a liquid. For nerve pain it is usually taken once a day, starting at 10 mg; for depression, the NHS says it may be taken three or four times a day or once daily, building up gradually. Your own dose may differ, so follow the label.

Swallow tablets whole with water, because they taste bitter if chewed. If you take it once a day, bedtime is best.

If you miss a dose, take it when you remember unless the next dose is near. Do not double up.

An overdose of a tricyclic can be dangerous. The NHS says to call 999 for a fast or irregular heartbeat, seizures, drowsiness or loss of consciousness, breathing difficulty or confusion, and otherwise to call NHS 111 for advice.

Mention heart problems, liver or kidney problems, epilepsy or electroconvulsive treatment, glaucoma and diabetes before you start. Tell the prescriber too if you have had thoughts of suicide or self-harm, if you might be pregnant, or if you have recently stopped another antidepressant.

The NHS describes dry mouth and constipation as common effects, usually mild and temporary, along with drowsiness. If an effect is persistent, speak to a pharmacist or prescriber.

The NHS lists strong opioid painkillers such as codeine, morphine, oxycodone and tramadol, which can raise the risk of drowsiness and breathing problems. Other antidepressants can affect how it works and risk very high blood pressure, even if the other medicine was stopped recently. Sodium valproate, valproic acid and cimetidine can raise nortriptyline levels. St John's wort should not be taken.

Alcohol is permitted but can increase drowsiness. Driving may be unsafe at first, until you know how it affects you.

The NHS says you may be advised to continue nortriptyline in pregnancy, particularly for depression, after your doctor weighs the risks and benefits. Only very small amounts pass into breast milk, but you should speak to your pharmacist or doctor first.

Do not stop suddenly. Withdrawal can cause sweating, nausea, anxiety, headache and insomnia, so the dose is lowered gradually. Suspected side effects can be reported to the MHRA Yellow Card scheme.