P - Contraindicated in pregnancy
L - Cautioned in lactation
Buspirone (Buspar) is a psychoactive drug and pharmaceutical medication of the piperazine and azapirone chemical classes. It is used primarily as an anxiolytic, but also to a lesser extent as an antidepressant. Bristol-Myers Squibb (BMS) gained Food and Drug Administration (FDA) approval for buspirone in 1986, and it went generic in 2001.
Buspirone exerts anxiolytic activity through high affinity for serotonin 5-HT1A and 5-HT2 receptors. It has moderate affinity for dopamine D2-receptors but no affinity for GABA receptors.
Absorption: Rapidly absorbed from the GI tract (oral); peak plasma concentrations after 40-90 minutes.
Distribution: Protein-binding: 95%.
Metabolism: Extensively hepatic via hydroxylation and oxidative dealkylation.
Excretion: Urine and faeces (as metabolites); 2-4 hr (elimination half-life).
In short term management of anxiety
Dizziness, nausea, headache, nervousness, lightheadedness, excitement, paraesthesia, sleep disturbances, chest pain, tinnitus, nasal congestion, sore throat. Less sedation and lower potential for dependence compared to other anxiolytics.
Interference With Cognitive and Motor Performance
Studies indicate that Buspirone is less sedating than other anxiolytics and that it does not produce significant functional impairment. However, its CNS effects in any individual patient may not be predictable. Therefore, patients should be cautioned about operating an automobile or using complex machinery until they are reasonably certain that Buspirone treatment does not affect them adversely.
While formal studies of the interaction of Buspirone hydrochloride with alcohol indicate that Buspirone does not increase alcohol-induced impairment in motor and mental performance, it is prudent to avoid concomitant use of alcohol and Buspirone.
Potential for Withdrawal Reactions in Sedative/Hypnotic/Anxiolytic Drug-Dependent Patients
Because Buspirone does not exhibit cross-tolerance with benzodiazepines and other common sedative/hypnotic drugs, it will not block the withdrawal syndrome often seen with cessation of therapy with these drugs. Therefore, before starting therapy with Buspirone, it is advisable to withdraw patients gradually, especially patients who have been using a CNS-depressant drug chronically, from their prior treatment. Rebound or withdrawal symptoms may occur over varying time periods, depending in part on the type of drug, and its effective half-life of elimination.
The syndrome of withdrawal from sedative/hypnotic/anxiolytic drugs can appear as any combination of irritability, anxiety, agitation, insomnia, tremor, abdominal cramps, muscle cramps, vomiting, sweating, flu-like symptoms without fever, and occasionally, even as seizures.
Possible Concerns Related to Buspirone’s Binding to Dopamine Receptors
Because Buspirone can bind to central dopamine receptors, a question has been raised about its potential to cause acute and chronic changes in dopamine-mediated neurological function (e.g., dystonia, pseudo-parkinsonism, akathisia, and tardive dyskinesia). Clinical experience in controlled trials has failed to identify any significant neuroleptic-like activity; however, a syndrome of restlessness, appearing shortly after initiation of treatment, has been reported in some small fraction of Buspirone-treated patients. The syndrome may be explained in several ways. For example, Buspirone may increase central noradrenergic activity; alternatively, the effect may be attributable to dopaminergic effects (i.e., represent akathisia).
Preceding co-administration of MAOIs, decreased hepatic or renal function. In patients on benzodiazepines, withdraw the drug gradually. May impair ability to drive or operate machinery.
Enhanced sedative effects with alcohol or CNS depressants. Increases serum haloperidol. Concurrent admin with MAOIs may lead to increase in BP.
Potentially Fatal: Elevation of BP when taken concomitantly with MAOIs.
Information Not Available
Short-term management of anxiety
Adult: Initially, 5 mg bid/tid increased by 5-mg increments at intervals of 2-3 days. Max: 45 mg daily in divided doses.
Max Dosage: 45 mg daily in divided doses.
May be taken with or without food. (Take consistently either always w/ or always without meals.)
Contraindicated in pregnancy.
Category B: Either animal-reproduction studies have not demonstrated a foetal risk but there are no controlled studies in pregnant women or animal-reproduction studies have shown an adverse effect (other than a decrease in fertility) that was not confirmed in controlled studies in women in the 1st trimester (and there is no evidence of a risk in later trimesters).
Contraindicated in lactation
The safety and effectiveness of Buspirone were evaluated in two placebo-controlled 6 week trials involving a total of 559 pediatric patients (ranging from 6 to 17 years of age) with GAD. Doses studied were 7.5 mg to 30 mg b.i.d. (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.
In one study of 6632 patients who received Buspirone for the treatment of anxiety, 605 patients were ≥ 65 years old and 41 were ≥ 75 years old; the safety and efficacy profiles for these 605 elderly patients (mean age = 70.8 years) were similar to those in the younger population (mean age = 43.3 years). Review of spontaneously reported adverse clinical events has not identified differences between elderly and younger patients, but greater sensitivity of some older patients can not be ruled out.
Hypersensitivity. Epilepsy; severe renal or hepatic impairment; children <18 yr; pregnancy, lactation.
Oral: Store at 15-30°C
Oral: Store at 15-30°C