Nefazodone


Full Prescribing Info
Dosage/Direction for Use

Oral
Depression
Adult: Usual initial dose 100 mg bid increased, if needed, in increments of 100-200 mg at intervals of at least a wk. Max: 300 mg bid.
Elderly: Initial dose: 50 mg bid.
Administration
May be taken with or without food.
Contraindications
Hypersensitivity to phenylpiperazine antidepressants. Active liver disease or elevated baseline serum transaminase concentrations. Previous history of hepatocellular injury with nefazodone use. Concurrent use or within 14 days of discontinuing treatment with MAOI.
Special Precautions
Epilepsy, bipolar disorders, CV or cerebrovascular disease that may be worsened by hypotension (e.g. recent history of MI, unstable heart disease, angina, or ischaemic stroke), any condition that may predispose patient to hypotension (e.g. dehydration or hypovolaemia). Pregnancy, lactation, elderly and children. May impair ability to drive or operate machinery. Withdraw gradually to reduce risk of withdrawal symptoms. Close monitoring during initial treatment and dosage adjustments due to possible worsening of depression and increased suicide risk. Monitor LFT regularly and advise patient to watch out for signs and symptoms of liver dysfunction (e.g. jaundice, anorexia, GI complaints, malaise) and report immediately if they occur. Withdraw drug in patients who develop evidence of hepatocellular injury (e.g. increased serum alanine aminotransferase or aspartate aminotransferase levels ≥3 times upper limit of normal. Discontinue treatment immediately if inappropriate or prolonged penile erections develops.
Adverse Reactions
Nausea, dry mouth, insomnia, somnolence, agitation, constipation, asthenia, dizziness, lightheadedness, orthostatic hypotension, confusion, blurred vision, abnormal vision, eye pain, sinus bradycardia, dyspnoea, bronchitis, syndrome of inappropriate secretion of anti-diuretic hormone, impotence.
Potentially Fatal: Severe and fatal hepatic failure.
Overdosage
Symptoms: Hypotension, dizziness, nausea, vomiting, drowsiness. Management: Treatment is supportive and symptomatic. Charcoal may be used if >1.5 g in an adult or 20 mg/kg in a child has been consumed and within 1 hr of ingestion. Gastric lavage may be performed. Dialysis, haemoperfusion, exchange perfusion, and forced diuresis unlikely to be of benefit due to extensive distribution.
Drug Interactions
Concurrent use may increase ciclosporin, cilostazol, mirtazapine, dutasteride concentrations. Concomitant use with nefazodone increases alprazolam concentration; a 50% reduction in the initial alprazolam dosage is recommended.
Potentially Fatal: Increased risk of severe and fatal reactions when used with MAOI; start nefazodone at least 14 days after MAOI discontinuation and start MAOI at least 7 days after stopping nefazodone. Inhibit metabolism of terfenadine, astemizole, cisapride, pimozide and increased risk of ventricular arrhythmias; avoid concurrent use. Decreased nefazodone levels and increased carbamazepine levels. Increased plasma level of eplerenone, ivabradine, reboxetine, tacrolimus, triazolam with nefazodone.
Action
Nefazodone, a phenylpiperazine antidepressant structurally related to trazodone, blocks serotonin reuptake at presynaptic neurones and is an antagonist at postsynaptic 5-HT2 receptors. It also blocks α1-adrenoceptors which may be associated with postural hypotension. Unlike trazodone, nefazodone inhibits noradrenaline reuptake. It does not have significant affinity for α2 and β- adrenergic, 5-HT1A, cholinergic, dopaminergic, or benzodiazepine receptors.
Absorption: Rapidly and completely absorbed but absolute bioavailability is variable and low (about 20%). Time to peak plasma concentration: 1 hr. Absorption delayed by food and bioavailability decreased by approx 20% (clinically not significant).
Distribution: Widely distributed including CNS, with small amounts distributed into breast milk. Volume of distribution: 0.22-0.87 L/kg. Protein binding: Extensively bound to human plasma proteins(>99%).
Metabolism: Undergoes extensive 1st pass metabolism to several metabolites, of which hydroxynefazodone and m-chlorophenylpiperazine, are pharmacologically active.
Excretion: Mainly as metabolites via the urine (about 55%) and the faeces (20-30%). Half-life: 2-4 hr.
Storage
Oral: Store at room temperature, below 40°C (104°F).
CIMS Class
Disclaimer: This information is independently developed by CIMS based on nefazodone from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to CIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, CIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2020 CIMS. All rights reserved. Powered by CIMSAsia.com
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