Drug Information for LOXITANE (Loxapine Succinate) Capsules Revised: March 2008 14750-1 Rx only (Watson Pharma, Inc.): CLINICAL PHARMACOLOGY

Pharmacodynamics:

Pharmacologically, loxapine is an antipsychotic for which the exact mode of action has not been established. However, changes in the level of excitability of subcortical inhibitory areas have been observed in several animal species in association with such manifestations of tranquilization as calming effects and suppression of aggressive behavior.

In normal human volunteers, signs of sedation were seen within 20 to 30 minutes after administration, were most pronounced within one and one-half to three hours, and lasted through 12 hours. Similar timing of primary pharmacologic effects was seen in animals.

Absorption, Distribution, Metabolism, and Excretion

Absorption of loxapine following oral or parenteral administration is virtually complete. The drug is removed rapidly from the plasma and distributed in tissues. Animal studies suggest an initial preferential distribution in lungs, brain, spleen, heart, and kidney. Loxapine is metabolized extensively and is excreted mainly in the first 24 hours. Metabolites are excreted in the urine in the form of conjugates and in the feces unconjugated.