Surmontil

Indications

Trimipramine is a tricyclic antidepressant used to treat depression, particularly when it comes with anxiety, agitation or poor sleep, because it has a calming, sedating effect.

How It Works

Trimipramine affects chemical messengers in the brain, including serotonin and noradrenaline, and blocks several receptors such as histamine H1, serotonin 5-HT2 and alpha-adrenergic receptors. These actions help lift mood over time, and the strong antihistamine effect causes drowsiness, which helps sleep. Improvement in mood usually takes 2 to 4 weeks or more.

Dosage and Administration

Take exactly as prescribed. The doctor starts with a low dose and increases it gradually, and older people usually need lower doses. It is often taken as a single dose in the evening because it causes drowsiness. Keep taking it even if you feel better, and do not stop suddenly, as this can cause withdrawal symptoms such as nausea, headache, restlessness and poor sleep; your doctor will reduce the dose slowly.

Interactions

• Do not use with, or within 2 weeks of stopping, MAO inhibitors (including Linezolid), because of a risk of serious reactions.
• SSRIs such as Fluoxetine, Paroxetine and Sertraline, and Tramadol, can raise Trimipramine levels and increase the risk of serotonin syndrome.
• Medicines that prolong the QT interval (such as Amiodarone, some antipsychotics and Macrolide antibiotics) increase the risk of heart rhythm problems.
• Alcohol, sedatives, antihistamines and opioids increase drowsiness.
• Other anticholinergic medicines add to dry mouth, constipation and urine retention.
• It may reduce the effect of some blood pressure medicines such as Clonidine, and interact with Adrenaline in local anaesthetics.
• Cimetidine and some antifungals may raise its levels; Carbamazepine and Rifampicin may lower them.

Contraindications

• Recent heart attack, heart block or other serious heart rhythm problems.
• Severe liver disease.
• Mania.
• Use with MAO inhibitors.
• Allergy to Trimipramine or other tricyclic antidepressants.
• Children, unless prescribed by a specialist.

Side Effects

Common effects include drowsiness, dry mouth, constipation, blurred vision, dizziness on standing, weight gain, sweating, fast heartbeat, difficulty passing urine and sexual problems.

Less common but serious effects include heart rhythm problems, seizures, confusion (especially in older people), low sodium, worsening of glaucoma, and in young people especially, new or worse thoughts of suicide early in treatment.

Get urgent medical help if you have thoughts of self-harm or suicide, fainting, a very fast or irregular heartbeat, chest pain, a seizure, severe eye pain with blurred vision, inability to pass urine, or high fever with stiffness, confusion and sweating.

Pregnancy and Lactation

Use in pregnancy only if your doctor decides the benefit is greater than the risk; use late in pregnancy may cause withdrawal symptoms in the newborn. Do not stop suddenly if you become pregnant; speak to your doctor. Small amounts pass into breast milk; ask your doctor before breastfeeding and watch the baby for drowsiness or poor feeding.

Precautions and Warnings

• Family and carers should watch for changes in mood, agitation or suicidal thoughts, particularly at the start of treatment or after dose changes.
• Use with care in heart disease, epilepsy, glaucoma, enlarged prostate, overactive thyroid, diabetes, liver or kidney disease and bipolar disorder.
• Do not drive or operate machinery if drowsy; avoid alcohol.
• Tell your doctor or dentist you take it before any surgery or anaesthetic.
• Prescriptions may be limited in quantity because overdose is dangerous.

Overdose

Overdose of tricyclic antidepressants is very dangerous and can cause dangerous heart rhythm problems, low blood pressure, seizures, coma and death. Call for emergency help immediately, even if the person seems well.

Therapeutic Class

Tricyclic antidepressant.

Storage

Store below 30°C in a dry place, away from light and out of the reach of children.