Amoxapine


Generic Medicine Info
Indications and Dosage
Oral
Depression
Adult: Initially, 50 mg bid or tid, may be increased up to 100 mg bid or tid by the end of 1st wk, based on response. For severely depressed patient in hospital: Up to 600 mg daily.
Elderly: Initially, 25 mg bid-tid increased as necessary after 5-7 days up to 150 mg daily. Max: 300 mg daily.
Administration
May be taken with or without food.
Contraindications
Acute recovery phase following MI. Concomitant or w/in 14 days of MAOI use.
Special Precautions
Patient w/ history of urinary retention, angle-closure glaucoma (w/o iridectomy), increased intraocular pressure; history of convulsive disorder, overt/latent seizure disorder; CV (e.g. MI, stroke, tachycardia, conduction abnormalities) and cerebrovascular diseases, hypovolaemia, decreased GI motility, paralytic ileus, BPH, xerostomia, visual problem, DM. Elderly. Hepatic and renal impairment. Pregnancy and lactation.
Adverse Reactions
Drowsiness, dry mouth, constipation, blurred vision; anxiety, insomnia, restlessness, nervousness, palpitations, tremors, confusion, excitement, nightmares, ataxia, alteration in EEG pattern, paraesthesia, tinnitus, disorientation, seizure, hypomania, numbness, incoordination, disturbed concentration, hyperthermia; oedema, skin rash, drug fever, urticaria, photosensitisation, pruritus, vasculitis, hepatitis; prolactin level elevation; nausea, epigastric distress, vomiting, flatulence, abdominal pain, peculiar taste, diarrhoea; dizziness, headache, fatigue, weakness, excessive appetite, increased perspiration; disturbance of accommodation, mydriasis, delayed micturition, urinary retention, nasal stuffiness; hypotension, HTN, syncope, tachycardia; leucopenia, agranulocytosis; increased/decreased libido, impotence, menstrual irregularity, breast enlargement, galactorrhoea (in females), syndrome of inappropriate antidiuretic hormone secretion; lacrimation, wt gain/loss, altered liver function, painful ejaculation. Rarely, tardive dyskinesia.
Potentially Fatal: Rarely, neuroleptic malignant syndrome (NMS).
Patient Counseling Information
This drug may cause drowsiness, if affected, do not drive or operate machinery.
Monitoring Parameters
Monitor closely for clinical worsening, suicidality or unusual behavioural changes. Monitor heart rate, BP, and ECG esp in older adults and patient w/ pre-existing cardiac disease. Measure wt, BMI, and blood glucose.
Overdosage
Symptoms: Grand mal convulsion, status epilepticus, coma, acidosis, acute tubular necrosis, rhabdomyolysis, myoglobinuria. Management: Symptomatic and supportive treatment w/ special attention to control of seizures. Induce emesis, then employ gastric lavage and activated charcoal. IV diazepam and/or phenytoin may be given to treat seizures.
Drug Interactions
May enhance the effects of barbiturates and other CNS depressants.
Potentially Fatal: May cause hypertensive crisis and severe convulsion w/ MAOIs.
Food Interaction
May enhance response to alcohol.
Action
Description:
Mechanism of Action: Amoxapine, a dibenzoxazepine TCA, is the N-desmethyl derivative of loxapine w/ actions similar to amitriptyline. It reduces the reuptake of norepinephrine and serotonin, and significantly blocks dopamine receptor activity.
Onset: 1-2 wk; may require 4-6 wk.
Pharmacokinetics:
Absorption: Rapidly and well absorbed from the GI tract. Time to peak plasma concentration: W/in 1-2 hr.
Distribution: Widely distributed throughout body tissues. Enters breast milk. Volume of distribution: 0.9-1.2 L/kg. Plasma protein binding: Approx 90%.
Metabolism: Extensively metabolised in the liver via hydroxylation, principally to 8-hydroxyamoxapine (8-OH-amoxapine), and to a lesser extent, to 7-hydroxyamoxapine (7-OH-amoxapine). Metabolites undergo conjugation to form glucuronides.
Excretion: Via urine (mainly as glucuronides, <5% as unchanged drug). Elimination half-life: 8 hr; 30 hr (as 8-OH-amoxapine).
Chemical Structure

Chemical Structure Image
Amoxapine

Source: National Center for Biotechnology Information. PubChem Database. Amoxapine, CID=2170, https://pubchem.ncbi.nlm.nih.gov/compound/Amoxapine (accessed on Jan. 20, 2020)

Storage
Store between 20-25°C.
MIMS Class
Antidepressants
ATC Classification
N06AA17 - amoxapine ; Belongs to the class of non-selective monoamine reuptake inhibitors. Used in the management of depression.
References
Amoxapine Tablet (Actavis Pharma, Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 21/09/2016.

Anon. Amoxapine. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 21/09/2016.

Buckingham R (ed). Amoxapine. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 21/09/2016.

McEvoy GK, Snow EK, Miller J et al (eds). Amoxapine. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 21/09/2016.

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