Clopixol/Clopixol-Acuphase/Clopixol Depot Mechanism of Action

Zuclopenthixol is a thioxanthene derivative with pronounced antipsychotic and specific dampening effect. The unspecific sedative effect wanes after a few weeks of treatment. The antipsychotic effect of neuroleptics is normally related to their dopamine receptor-blocking effect, which seems to release a chain reaction as other transmitter systems are influenced as well.
The specific dampening effect of zuclopenthixol makes it particularly useful in the treatment of psychotic patients, who are agitated, restless, hostile or aggressive.
Clopixol-Acuphase: A single injection of zuclopenthixol acetate ensures a pronounced and rapid reduction in psychotic symptoms. The duration of action is 2-3 days and normally only 1 or 2 injections are sufficient before the patient can be switched to maintenance treatment.
Zuclopenthixol acetate induces a transient dose-dependent sedation. However, such an initial sedation is often advantageous in the acute/subacute phase of the psychosis. The unspecific sedation is present rapidly after the injection, is significant after 2 hrs and reaches its maximum in about 8 hrs, whereupon it declines substantially and remains weak inspite of repeated injection.
Clopixol Depot: Zuclopenthixol decanoate has a considerably prolonged duration of action. It is especially useful in patients, who refuse to take drugs and in outpatients, who are unreliable in taking oral medication on their own as it permits continuous antipsychotic treatment and thus prevents the frequent relapses caused by failure to take oral medication.
Pharmacokinetics: Clopixol: The bioavailability after oral administration is 44% on an average. Maximal serum concentration is reached in about 4 hrs. Zuclopenthixol in small amounts crosses the placental barrier and is excreted in small amounts into the breast milk. The metabolites are devoid of psychopharmacological activity. The excretion proceeds mainly with feces but also to some degree with the urine. The biological half-life is about 20 hrs.
Clopixol-Acuphase: Maximum serum concentration of zuclopenthixol is reached on an average of 36 hrs after injection, then the serum curve declines slowly. Three days after the injection, the serum level is about ¹/₃ of the maximum. Zuclopenthixol in small amounts crosses the placental barrier and is excreted in amounts with the milk. The metabolites are devoid of psychopharmacological activity. The excretion proceeds mainly with feces but also to some degree with the urine.
Clopixol Depot: Clinical studies have shown that zuclopenthixol decanoate injections can be given with intervals of 2-4 weeks. The maximum serum concentration is reached by the end of the 1st week after injection. The serum concentration curve declines exponentially with a half-life of 19 days reflecting the rate of release from the depot.