Trade Names:BuSpar- Tablets 5 mg (4.6 mg as base)- Tablets 10 mg (9.1 mg as base)- Tablets 15 mg (13.7 mg as base)- Tablets 30 mg (27.4 mg as base)
Apo-Buspirone (Canada)CO Buspirone (Canada)Gen-Buspirone (Canada)PMS-Buspirone (Canada)ratio-Buspirone (Canada)Mechanism unknown; does not exert anticonvulsant or muscle relaxant effects.
Rapidly absorbed. C max is 1 to 6 mg/mL. T max is 40 to 90 min.
About 86% bound to plasma proteins.
Extensive first-pass metabolism. Primarily metabolized by oxidation (which is mediated by CYP3A4) to active metabolite.
Within 24 h, 29% to 63% excreted in urine, primarily as metabolites; 18% to 38% is excreted in feces. The t ½ is about 2 to 3 h.
AUC increased 4-fold.
Hepatic Function ImpairmentAUC increased 13-fold.
Treatment of anxiety disorders; short-term relief of anxiety symptoms.
Reduction of symptoms of PMS.
Standard considerations.
PO 7.5 mg twice daily; may increase by 5 mg/day every 2 to 3 days as needed (max, 60 mg/day in divided doses).
Store tablets below 86°F.
Dizziness, headache, and nausea can occur.
FluoxetineBuspirone effects may be decreased. Paradoxical worsening of obsessive-compulsive disorder (OCD) may occur.
HaloperidolBuspirone may increase haloperidol plasma levels.
Inducers of CYP3A4 (eg, carbamazepine, dexamethasone, phenobarbital, phenytoin, rifampin)May reduce buspirone plasma levels, decreasing the therapeutic effect.
Inhibitors of CYP3A4 (eg, diltiazem, erythromycin, grapefruit juice, itraconazole, ketoconazole, nefazodone, ritonavir, verapamil)May elevate buspirone plasma levels, increasing the pharmacologic and adverse effects.
MAOIs (eg, isocarboxazid)Risk of elevated BP may be increased. Do not administer buspirone with or within 14 days of MAOI administration.
NefazodoneIf used with buspirone, a low dose (eg, 2.5 mg/day) is recommended.
TrazodoneALT may be elevated.
None well documented.
Chest pain (at least 1%); tachycardia/palpitations (1%).
Dizziness (12%); drowsiness (10%); headache (6%); nervousness (5%); lightheadedness (3%); excitement, numbness, anger/hostility, confusion, weakness (2%); paresthesia, incoordination, tremor (1%); dream disturbances (at least 1%); cogwheel rigidity, dizziness, dystonic reactions, ataxia, extrapyramidal effects, dyskinesias (acute and tardive), emotional lability, serotonin syndrome, difficulty in recall (postmarketing).
Skin rash, sweating/clamminess (1%); ecchymosis (postmarketing).
Blurred vision (2%); tinnitus, sore throat, nasal congestion (at least 1%); visual changes (postmarketing).
Nausea (8%); diarrhea (2%).
Urinary retention (postmarketing).
Aches/pains (1%).
Allergic reactions (including urticaria), angioedema (postmarketing).
Category B .
Undetermined. Breast-feeding should be avoided.
The safety and efficacy of buspirone were evaluated in 2 placebo-controlled, 6-wk trials involving a total of 559 pediatric patients (ranging from 6 to 17 yr of age) with generalized anxiety disorder (GAD). Doses studied were 7.5 to 30 mg twice daily (15 to 60 mg/day). There were no significant differences between buspirone and placebo with regard to the symptoms of GAD following doses recommended for the treatment of GAD in adults. Pharmacokinetic studies have shown that, for identical doses, plasma exposure to buspirone and its active metabolite, 1-PP, are equal to or higher in pediatric patients than adults. No unexpected safety findings were associated with buspirone in these trials. There are no long-term safety or efficacy data in this population.
Administration of buspirone not recommended.
Administration of buspirone not recommended.
Nausea, vomiting, dizziness, drowsiness, miosis, gastric distress.
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