Trazodone: uses, side effects and priapism warning

The NHS describes trazodone as an antidepressant for depression and anxiety. It works by raising chemicals in the brain linked to mood, such as serotonin.

Many people know it as a sedating antidepressant. The NHS page does not make claims about sleep treatment as such, but it does say that bedtime dosing is recommended if you are having trouble sleeping.

Trazodone comes as tablets, capsules or a liquid. Swallow tablets and capsules whole with water, once or twice a day. Take them with or just after food, which the NHS says reduces the risk of side effects.

Because the NHS lets the prescriber choose between once and twice daily dosing, the timing on your own label is the one to follow. If you find yourself drowsy in the morning, mention it at review; the timing of doses can be looked at. Keep all your medicines in one place and avoid taking anything else that makes you sleepy unless a pharmacist has checked it.

If you miss a dose, take it as soon as you remember unless the next dose is almost due. In that case skip it, and never take two together.

If you take too much, call NHS 111 straight away and bring the packet and a list of your other medicines if you go to A&E.

Many of the common effects relate to its calming action.

• Common: feeling sleepy, dizzy or tired, headaches, nausea, constipation, muscle pain and dry mouth.

• Do not drive, cycle or use machinery if you feel sleepy, dizzy or tired.

• Call NHS 111 for an allergic reaction, priapism (a long-lasting, painful erection), a blood disorder, yellowing of the skin (jaundice) or thoughts of suicide.

Priapism is an erection that lasts for many hours and is painful. The NHS lists it as a serious side effect of trazodone. Because tissue can be damaged if it is not treated promptly, it is a reason to seek urgent help and not to wait for an appointment.

The NHS says trazodone may not be suitable if you have had an allergic reaction to it, have a history of self-harm or bipolar disorder, or have heart, kidney or liver problems, epilepsy or an overactive thyroid.

The NHS lists other antidepressants, antifungal medicines, epilepsy medicines, sedatives, erythromycin, levodopa and warfarin as medicines to check, and says to avoid St John's wort. It is best not to drink alcohol, which increases the risk of side effects.

Trazodone can be used during pregnancy at the lowest effective dose with close monitoring. It passes into breast milk, so talk to your doctor about feeding.

Do not stop suddenly. Your doctor will lower the dose gradually over several weeks or months. Suspected side effects can be reported to the MHRA Yellow Card scheme.