Quetiapine: uses, side effects and monitoring

Quetiapine is an antipsychotic. The NHS lists three situations: schizophrenia, bipolar disorder, and severe depression, where it is given together with other medicines. The page does not describe the exact mechanism, but antipsychotics as a group act on brain chemistry to settle symptoms such as disturbed thinking or extreme mood swings.

The same tablet can therefore be prescribed for quite different conditions, and the amount, timing and length of treatment will reflect which one applies to you.

Tablets are swallowed whole with a glass of water. Do not split, chew or crush them. The NHS says you take quetiapine once or twice a day, with or without food, and that a liquid form exists for people who cannot take tablets.

Most people begin on a low dose which is increased over the first few days. After that, the dose depends on the condition being treated, so there is no single standard amount to quote here.

If you miss a dose, take it as soon as you remember unless the next dose is near, when you should skip it. Do not take a double dose.

The NHS says that if you take more than prescribed it can be dangerous. Call NHS 111, and if you go to A&E, take the packet and a list of your other medicines.

Quetiapine can cause a range of everyday effects, many of which settle. If one persists or troubles you, report it to the prescriber rather than changing the dose.

• Common: dry mouth, dizziness, constipation, a fast heartbeat, drowsiness, tiredness, problems sleeping, feeling irritated or agitated, missed or irregular periods, shaking, muscle stiffness or difficulty moving, and putting on weight.

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

• The NHS lists anaphylaxis, severe skin reactions such as Stevens-Johnson syndrome, metabolic problems and liver problems as serious effects. Call NHS 111 if you suspect one, and 999 for signs of anaphylaxis.

The NHS says quetiapine may be unsuitable if you have had an allergic reaction to it, have a personal or family history of heart conditions, have low blood pressure, liver or kidney problems, diabetes, seizures, or a history of alcohol or drug misuse. Tell the prescriber about each of these.

Certain medicines can raise or lower the effect of quetiapine. The NHS names some heart medicines, HIV treatments, antibiotics such as erythromycin and clarithromycin, antifungal medicines such as clotrimazole and fluconazole, and nefazodone, an antidepressant.

Alcohol is allowed, but it is best not to drink a lot because it can make you sleepy. Avoid grapefruit juice.

The NHS says quetiapine can be used during pregnancy if needed, at the lowest effective dose, and that your baby's growth may be checked more often than usual. It also says breastfeeding is possible; your baby will be checked regularly for irritability, drowsiness and weight gain.

Do not stop it suddenly because that can cause withdrawal symptoms. The dose is reduced gradually. Suspected side effects can also be reported to the MHRA Yellow Card scheme.