Adult: Initially, 30-40 mg daily in divided doses or as a single dose at bedtime, gradually increase the dose as necessary. Usual dose: 30-90 mg daily. Max: 200 mg daily in divided doses. Elderly: Initially, 30 mg daily, gradually increase dose as necessary. Maintenance dose: Dose reduction may be required.
May be taken with or without food.
Mania. Concomitant use with MAOIs. Lactation. Severe hepatic impairment.
Patient with suicidal ideation or history of suicide-related events; existing or history of CV disease (e.g. recent MI, heart block, arrhythmia), at risk for QT prolongation or torsade de pointes (e.g. congenital long QT syndrome, structural heart disease, or left ventricular dysfunction); seizure or at risk of seizure (e.g. history of seizure, head trauma, brain damage, alcoholism), diabetes mellitus, bipolar disorder, phaeochromocytoma, cerebrovascular disease, hypovolaemia; decreased gastrointestinal motility, angle-closure glaucoma, increased intraocular pressure, urinary retention, paralytic ileus, benign prostatic hyperplasia, xerostomia, visual problems. Female. Patient undergoing surgery. Avoid abrupt withdrawal. Renal and hepatic impairment. Elderly. Pregnancy.
Significant: Suicidal ideation and behaviour, precipitate shift to mania or hypomania (if with bipolar disorder), bone fracture, orthostatic hypotension, QT prolongation, ventricular arrhythmias, anticholinergic effects (e.g. constipation, xerostomia, blurred vision, urinary retention); bone marrow suppression presenting as granulocytopenia, agranulocytosis, leucopenia, aplastic anaemia. General disorders and administration site conditions: Oedema. Hepatobiliary disorders: Hepatic disorder, jaundice. Metabolism and nutrition disorders: Hyponatraemia. Musculoskeletal and connective tissue disorders: Arthralgia, arthritis, polyarthropathy. Nervous system disorders: Dizziness, headache, tremor, seizure. Psychiatric disorders: Withdrawal symptoms. Reproductive system and breast disorders: Breast disorder (e.g. gynaecomastia, non-peurperal lactation, nipple tenderness). Skin and subcutaneous tissue disorders: Rash, sweating. Potentially Fatal: Serotonin syndrome.
Patient Counseling Information
This drug may cause drowsiness or reduced alertness, if affected, do not drive or operate machinery.
Evaluate mental status. Monitor signs of suicidal ideation and behaviour, clinical worsening and unusual behavioural changes especially at the start of therapy or when doses are increased or decreased. Monitor CBC every 4 weeks during the 1st 3 months of therapy then periodically; blood pressure, heart rate, ECG (for older adults, with pre-existing cardiac disease or at risk of QTc prolongation), electrolytes (e.g. serum K, Mg), serum glucose, LFT, and renal function; signs of infection or serotonin syndrome.
Symptoms: Nausea, vomiting, dry mouth, constricted or dilated pupils, nystagmus, ataxia, dizziness, drowsiness, slow tendon reflexes, prolonged sedation, CV effects (e.g. bradycardia, tachycardia, hypotension, hypertension), respiratory depression, ECG abnormalities (e.g. ST elevation), 1st degree to complete heart block, convulsions, coma; ventricular fibrillation and cardiac arrest (severe cases). Management: Symptomatic and supportive treatment. May administer activated charcoal (adult: 50 g; children: 1 g/kg) within 1 hour of ingestion of more than 5 mg/kg of bodyweight. Obtain and check urea, electrolyte and glucose levels. Perform 12 lead ECG, and in case of abnormalities, perform an arterial blood gas test. Monitor blood pressure, pulse and cardiac rhythm. Correct hypotension by raising the foot of the bed and by giving an appropriate fluid challenge. In case severe hypotension persists despite performing appropriate measures, consider central venous pressure monitoring. If hypotension is primarily caused by decreased systemic vascular resistance, may consider drugs with α-adrenergic activity (e.g. norepinephrine or high dose dopamine [10-30 mg/kg/minute]) wherein dose is titrated against blood pressure. If hypotension is caused by decreased cardiac output, may consider inotropic drugs (e.g. dobutamine), or in severe cases, may consider epinephrine. Administer atropine IV (adult: 0.5-1.2 mg; child: 0.02 mg/kg) for symptomatic bradycardia. Consider dobutamine or isoprenaline for bradycardia due to hypotension; temporary pacemaker insertion may be needed or may use external pacing. Administer IV diazepam (adults: 10-20 mg; children: 0.1-0.3 mg/kg) or lorazepam (adult: 4 mg; child: 0.1 mg/kg) for frequent or prolonged convulsions; may consider administration of phenobarbital (10 mg/kg at max rate of 100 mg/minute; max dose: 1 g) if unresponsive to prior management. Alternatively, may administer phenytoin (loading dose: 18 mg/kg via IV infusion for adults and children over 20-30 minutes at max rate of 50 mg/minute).
May potentiate central nervous depressant effect of anxiolytics, hypnotics, and antipsychotics. Decreased serum concentration with carbamazepine, phenobarbital, phenytoin. May antagonise the anticonvulsant effect of antiepileptics, barbiturates, primidone. May increase the risk of convulsions with atomoxetine. May enhance the hypotensive effect with diazoxide, hydralazine, nitroprusside. May increase antimuscarinic effects with antihistamine and antimuscarinics. Potentially Fatal: Increased risk of serotonin syndrome with serotonergic agents (e.g. TCAs, triptans, lithium, tramadol, fentanyl, buspirone, tryptophan) or drugs that impair metabolism of serotonin (e.g. MAOIs, linezolid, IV methylene blue).
May potentiate central nervous depressant effect of alcohol. May ncrease risk of serotonin syndrome with St. John’s wort.
Description: Mianserin increases central noradrenergic neurotransmission by blocking the presynaptic α2-autoreceptor and inhibiting noradrenaline-reuptake. Additionally, it has an interaction with serotogenic receptors in the CNS, antihistamine property and α1-antagonistic activity. Pharmacokinetics: Absorption: Readily absorbed from the gastrointestinal tract. Bioavailability: Approx 20-70%. Time to peak plasma concentration: Approx 3 hours. Distribution: Widely distributed throughout the body; crosses the blood-brain barrier. Plasma protein binding: Approx 95%. Metabolism: Extensive first-pass metabolism in the liver; metabolised via oxidation and demethylation followed by conjugation. Excretion: Mainly via urine; faeces (small amounts). Elimination half-life: Approx 6-61 hours.