BuSpar is an anti-anxiety medication that is not chemically or pharmacologically related to benzodiazepines, barbiturates, or other sedative/anxiolytic drugs.
Bristol-Myers Squibb gained approval from the FDA for Buspirone in 1986, and the drug went generic in 2001.
Buspirone’s mechanism of action is not known. BuSpar differs from typical benzodiazepines in that it does not exhibit muscle-relaxing or anticonvulsant effects. As well, it lacks the prominent sedative effect associated with other anxiolytic drugs.
Pre-clinical studies have shown buspirone to have a high affinity for serotonin receptors. It has no significant affinity for benzodiazepine receptors, but has moderate affinity for dopamine receptors in the brain. Some studies do suggest the drug may have indirect effects on other neurotransmitter systems.
Indications and Dosage:
BuSpar is indicated for the management of anxiety disorders or short-term relief of anxiety symptoms, but not for anxiety or tension associated with the stress of everyday life.
The recommended initial dose is 15mg per day (5mg 3 times a day). To reach optimal therapeutic response, the dosage may be increased 5mg per day every 2 or 3 days, as needed. The maximum daily dosage should not exceed 60mg. In clinical trials, divided dosages of 20 to 30mg/day were common.
Buspar Side Effects and Interactions:
Side effects are rarely dangerous or intense. Some tend to disappear with continued use, or become less frequent if the initial dose is low and gradually increased.
The most frequent side effects include vertigo, headache, agitation, nausea, nervousness, light-headedness. Less frequent symptoms include insomnia, confusion, depression, difficulty concentrating, drowsiness, intestinal disorders, paresthesia, tremors, coordination disorders, tinnitus, disturbed visus, fatigue, weakness, Angina pectoris, sore throat, tachycardias, palpitations, dry mouth, muscle and joint pain.
Other, rare symptoms may include allergic reactions, subdermal bleeding, extrapyramidal symptoms, tunnel vision, urine retention, alopecia, hallucinations, psychosis, ataxia, epileptic seizures, syncope, pruritus, and urine retention. However, the dyscognitive side effects of benzodiazepines are completely lacking.
Other side effects have been reported, but with no more frequency than those encountered in placebo. An abnormal side effect reported has been an enhanced sense of smell.
Drugs or substances that may interact with BuSpar include:
- Haloperidol – increased plasma-levels of Haloperidol
- Rifampizin – decreased plasma-levels of Buspirone
- MAO-Inhibitors – severe hypertensive crises are possible
- Grapefruit/juice/extract – drastic increase in plasma-levels of Buspirone
Information for Parents and Kids:
A recent pediatric study for BuSpar found that, while successful in treating generalized anxiety disorder (GAD) in adults, was not helpful in treating certain types of anxiety in children. Researchers say more testing is needed in order to learn about the effects of these drugs on the immature brain.
Buspirone has not been studied in pregnant women, but has not been shown to cause birth defects or other problems in animal studies. It is currently unknown whether buspirone passes into human breast milk. The safety and efficacy of buspirone is unknown in children under the age of 18.
Warnings and Precautions:
For people taking MAO Inhibitors, the addition of buspirone may pose a health hazard. Reports of elevated blood pressure have occurred. It is therefore recommended that buspirone not be used with an MAOI.
Buspirone has no established antipsychotic activity, and should not be used in lieu of appropriate antipsychotic treatment. Studies have shown that buspirone is less sedating that other anxiolytics and that it does not produce substantial functional impairment. However, its effects on the central nervous system in an individual may be unpredictable. Thus, patients should be cautioned about operating automobiles or using complex machinery until they are sure the treatment will not adversely affect them.
Because buspirone does not exhibit cross-tolerance with sedative/hypnotic drugs such as benzodiazepines, it will not block the withdrawal syndrome often seen when ceasing these types of medications.
The syndrome of withdrawal from sedatives, hypnotics, and anxiolytics can appear as any combination of anxiety, insomnia, tremors, agitation, irritability, abdominal cramping, muscle cramping, vomiting, flu-like symptoms (without fever), sweating, and sometimes even seizures.
Over-dosage & Contraindications:
In clinical trials, doses as high as 375mg/day were administered to health men. In approaching this dosage, symptoms such as nausea, dizziness, vomiting, drowsiness, miosis, and gastric distress were seen. No deaths have been reported in humans either with deliberate or accidental overdose of buspirone.
Contraindications with buspirone usage may include Myasthenia gravis (“grave muscle weakness”), severely compromised liver- and renal-function, acute closed-angle glaucoma, concomitant treatment with a MAOI (severe hypertensive crises have been observed), and those with preexisting heart conditions (such as myocardial infarction) should exercise caution.
Generic Name: Buspirone
Chemical Formula: C21H31N502
Routes of Administration: oral
Elimination Half Life: 2 to 3 hours
Legal Status: by prescription only