Alprazolam

Alprazolam

Class:Tranquilizer,Sedative and hypnotic

Mechanism of action

Binds to stereospecific benzodiazepine receptors on the postsynaptic GABA neuron at several sites within the central nervous system,including the limbic system,reticular formation.Enhancement of the inhibitory effect of GABA on neuronal excitability results by increased neuronal membrane permeability to chloride ions.This shift in chloride ion result in hyperpolarization(a less excitable state) and stabilization.

Pharmacokinetics

Onset of action:within 1 hour.Duration:variable,8-24 hours.Distribution:vd:0.9-1.2l/kg;distributes into breast milk.Protein binding:80 percent.Metabolism:extensive in the liver.Half life:12-15 hours.Time to peak serum concentration:withion 1-2 hour.Elimination:urine.

Indication

Treatment of anxiety disorder( GAD);panic disorder,with or without agoraphobia;anxiety associated with depression.

Contraindication

Hypersensitivity to this drug or any component of its formulation.narrow angle glaucoma;concurrent use of ketoconazole and itraconazole;pregnancy.

Precautions

Rebound or withdrawal symptoms,including seizures may occur 18 hours to 3 days following abrupt discontinuation or large decrease in dose(more common in patients receiving >4mg/day).Use with caution in renal impairment or obese patients.

Side effects

Drowsiness,dizziness,fatigue,decreased libido,hypotension,ataxia,memory impairment,muscle cramps,nasal congestion.

Pregnancy

Pregnancy risk factor D.

Drug interactions

Cimetidine,ciprofloxacin,clariyhromycin,CNS depressants,digoxin,diltiazem,grapefruit juice,ketoconazole,fluoxetine,metronidazole,omeprazole.phenytoin,ritonavir,valproic acid may increase the serum level and/or toxicity of alprazolam.

Dosage

Oral:Adults:Anxiety:Effective doses are 0.5-4mg/day individed doses;the manufacturer recommends starting at 0.25-0.5mg 3 times per day,maximum 4mg/day.Depression:2.5-3mg/day individed doses.Panic disorder:2mg/day.

Brands

Tabs.ALP 0.25,0.5,1 mg,Tabs.Hilaxin,Tabs,Xanax,Tabs,Praz,Tabs.Neuxam,Tabs,Zenith.