Buspirone

Buspirone (brand-names Ansial®, Ansiced®, Anxiron®, Axoren®, Bespar®, Buspar®, Buspimen®, Buspinol®, Buspisal®, Narol®) is an anxiolytic drug. more...

It shows no potential for addiction compared to other drugs commonly prescribed for anxiety, especially benzodiazepine medications. The development of tolerance has not been noticed. Cross-tolerance to benzodiazepines, barbiturates and alcohol does not exist. Furthermore, it is non-sedating. It is thought to act by interfering with the function of the neurotransmitter serotonin in the brain, particularly by serving as a 5-HT1A receptor partial agonist. Additionally, it acts as a mixed agonist/antagonist on postsynaptic Dopamine receptors. GABA-mediated effects are lacking. Buspirone may also have indirect effects on other neurotransmitters in the brain. The action of a single dose is much longer than the short halflife of 2-3 hours indicates.

The bioavailability of Buspirone is very low and variable due to extensive first pass metabolism. The drug is quickly resorbed. Taking the drug together with food may increase the bioavailabilty. The drug is highly (95%) plasma-bound. The active metabolite 1-PP is also a 5-HT1A partial agonist with anxiolytic properties, but weaker so than the mother-drug.

Bristol-Myers Squibb gained FDA approval for Buspirone in 1986. The drug went generic in 2001.

It is also useful as an augmenting agent, for the treatment of depression, when added to SSRIs (selective serotonin reuptake inhibitors).

The main disadvantage is that 1 to 3 weeks elapse before the anxiolytic activity becomes evident. Often patients have to be initially cotreated with a benzodiazepine for immediate anxiolysis. Generally, Buspirone works less well than benzodiazepines. It is particular difficult to treat patients pretreated with benzodiazepines knowing the immediate effects of these tranqulizers.

Indications

• Generalized anxiety disorder of mild to moderate intensity

N.B. Busprirone is definitively not effective against other types of panic disorders with or without agoraphobia and social phobia.

• Augmention of SSRI-Treatment against Depression

Contraindications

• Myasthenia gravis
• Acute closed angle glaucoma
• Severly compromised liver- and renal-function
• Concomittant treatment with a MAO-Inhibitor (severe hypertensive crises have been seen)
• Caution : Preexisting heart conditions (e.g. myocardial infarction)

Side-effects

Rarely, side-effects have a dangerous nature or intensity. Some tend to disappear with continued therapy, or are less frequent if the initial dose is low and increased gradually (vertigo, agitation, insomnia).

• Most frequent: vertigo, headaches, nervousness, agitation, light-headedness, nausea;
• Often (>1%) : drowsiness, insomnia, concentration disorders, confusion, depression, agitation, intestinal disorders, paresthesia, coordination disorders, tremors, disturbed visus, tinnitus, fatigue, weakness, Angina pectoris, sore throat, tachycardias, palpitations, dry mouth, pain in muscles and joints;
• Seldomly: allergic reactions, subdermal bleeding, extrapyramidal symptoms, hallucinations, psychosis, ataxia, epileptic seizures, syncope, tunnel vision, urine retention, alopecia, pruritus.

The dyscognitive side-effects of benzodiazepines are lacking completely.

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