AZAPERONE
Chemistry - A butyrephone neuroleptic, azaperone occurs as a white to yellowish-white macro-crystalline powder with a melting point between 90 - 95°C. It is practically insoluble in water and 1gram is soluble in 29 ml of alcohol.
P/M; Mallinckrodt). It is also used clinically as a general tranquilizer for swine, in aggressive sowsto allow piglets to be accepted, and as a preoperative agent prior to general anesthesia or cesariansection with local anesthesia.
Azaperone has also been used as a neuroleptic in horses, but some horses develop adverse reactions (sweating, muscle tremors, panic reaction, CNS excitement) and IV administration has resultedin significant arterial hypotension in the horse. Because of these effects, most clinicians avoid theuse of this drug in equines.
Contraindications/Precautions - When used as directed, the manufacturer reports no contraindications for the drug. It should not be given IV as a significant excitatory phase may be seen in pigs.
Pigs should be left undisturbed after injection (for approximately 20 minutes) until the drug's fulleffects have been expressed, as disturbances during this period may trigger excitement.
Azaperone has minimal analgesic effects and is not a substitute for appropriate anesthesia oranalgesia. It is recommended that in large boars dosage not exceed 2 mg/kg IM.
Overdosage - No specific information was discovered regarding overdoses of azaperone, but itwould be expected that symptoms would be an extension of its pharmacologic effects. It is suggested that treatment be supportive. Do not use epinephrine to treat cardiovascular symptoms. Morework needs to done before 4-aminopyridine can be recommended as a reversal agent for azaperone.
Storage, Stability, Compatibility
Azaperone should be stored at room temperature (15-30°C)and away from light. No information was located regarding mixing azaperone with other compounds.Pharmacology - AZAPERONE
The butyrephenones as a class cause tranquilization and sedation (sedation maybe less so than with the phenothiazines), anti-emetic activity, reduced motor activity, and inhibitionof CNS catecholamines (dopamine, norepinephrine). Azaperone appears to have minimal effects onrespiration and may inhibit some of the respiratory depressant actions of general anesthetics. Aslight reduction of arterial blood pressure has been measured in pigs after IM injections ofazaperone, which is apparently due to slight alpha-adrenergic blockade. Azaperone has beendemonstrated to prevent the development of halothane-induced malignant hyperthermia in susceptible pigs. Preliminary studies have suggested that the effects of butyrephenones may be antagonized by 4-aminopyridine.Uses, Indications
Azaperone is officially indicated for the "control of aggressiveness whenmixing or regrouping weanling or feeder pigs weighing up to 36.4 kg" (Package Insert, Stresnil® -P/M; Mallinckrodt). It is also used clinically as a general tranquilizer for swine, in aggressive sowsto allow piglets to be accepted, and as a preoperative agent prior to general anesthesia or cesariansection with local anesthesia.
Azaperone has also been used as a neuroleptic in horses, but some horses develop adverse reactions (sweating, muscle tremors, panic reaction, CNS excitement) and IV administration has resultedin significant arterial hypotension in the horse. Because of these effects, most clinicians avoid theuse of this drug in equines.
Pharmacokinetics - AZAPERONE
Minimal information was located regarding actual pharmacokinetic parameters, but the drug is considered to have a fairly rapid onset of action following IM injections in pigs (5-10 minutes) with a peak effect at approximately 30 minutes post injection. It has a duration ofaction of 2-3 hours in young pigs and 3-4 hours in older swine. The drug is metabolized in the liver with 13% of it excreted in the feces. At 16 hours post-dose, practically all of the drug is eliminated from the body.Contraindications/Precautions - When used as directed, the manufacturer reports no contraindications for the drug. It should not be given IV as a significant excitatory phase may be seen in pigs.
Adverse Effects, Warnings
Transient salivation, piling, and shivering have been reported in pigs.Pigs should be left undisturbed after injection (for approximately 20 minutes) until the drug's fulleffects have been expressed, as disturbances during this period may trigger excitement.
Azaperone has minimal analgesic effects and is not a substitute for appropriate anesthesia oranalgesia. It is recommended that in large boars dosage not exceed 2 mg/kg IM.
Overdosage - No specific information was discovered regarding overdoses of azaperone, but itwould be expected that symptoms would be an extension of its pharmacologic effects. It is suggested that treatment be supportive. Do not use epinephrine to treat cardiovascular symptoms. Morework needs to done before 4-aminopyridine can be recommended as a reversal agent for azaperone.