Antipsychotic drugs parenteral formulations

Parenteral formulations of certain antipsychotic drugs (e.g., fluphenazine, haloperidol) are available for rapid initiation of treatment and for maintenance therapy in noncompliant patients. 

Buspirone is an azapirone anxiolytic that acts as a partial 5-HT agonist. In contrast to the BZDs, this agent has no immediate effect on the anxiety seen in patients undergoing medical procedures (e.g., endoscopy, cardioversion). Further, it cannot be given parenterally, because the drug is not available in an i.v. or i.m. formulation. Buspirone does not produce disinhibition euphoria and even in high doses has not been found to have antipsychotic activity. 

CNS Scopolamine is standard therapy for motion sickness this drug is one of the most effective agents available for this condition. A transdermal patch formulation is available. Benztropine, biperiden. and trihexyphenidyl are representative of several antimuscarinic agents used in parkinsonism. Although not as effective as levodopa (see Chapter 28), these agents may be useful as adjuncts or when patients become unresponsive to levodopa. Benztropine is sometimes used parenterally to treat acute dystonias caused by antipsychotic medications. 

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