I wish to know why there is an interaction between this drug and proton-pump inhibitors such as omeprazol. Does that have to do with the elimination-process? I have a patient that is a rapid metabolizer for CYP2C19(has both alleles variant *17), and he has a very low blood level of zuclopentixol with 200mg/2wks i.m., so, if both drugs are metabolized through CYP2C19, which I couldn't find on the internet, that would explain it. Omeprazol is apparently metabolized through CYP2C19. Does anyone know?
It is most likely not in the interaction checker because Zuclopenthixol is not used in the states.
(British Approved Name Modified, rINNM)
INNs in main languages (French, Latin, and Spanish):
Synonyms: Zuclopenthixol Dihydrochloride; Zuclopentixol, hidrocloruro de
BAN: Zuclopenthixol Hydrochloride [BANM]
INN: Zuclopenthixol Hydrochloride [rINNM (en)]
INN: Hidrocloruro de zuclopentixol [rINNM (es)]
INN: Zuclopenthixol, Chlorhydrate de [rINNM (fr)]
INN: Zuclopenthixoli Hydrochloridum [rINNM (la)]
INN: Зуклопентиксола Гидрохлорид [rINNM (ru)]
Molecular formula: C22H25ClN2OS,2HCl =473.9
ATC code: N05AF05
Pharmacopoeias. In British.
BP2008 (Zuclopenthixol Hydrochlonde). An off-white granular powder. Very soluble in water sparingly soluble in alcohol slightly soluble in chloroform very slightly soluble in ether. A 1% solution in water has apH of 2.0 to 3.0. Protect from light.
Adverse Effects, Treatment, and Precautions
As for Chlorpromazine. Zuclopenthixol is less likely to cause sedation but extrapyramidal effects are more frequent.
Porphyria. Zuclopenthixol is considered to be unsafe in patients with porphyria because it has been shown to be porphyrinogenic in animals.
As for Chlorpromazine.
Zuclopenthixol is absorbed after oral doses with peak plasma concentrations occurring 3 to 6 hours later. The biological half-life after oral doses is reported to be about 1 day. Paths of metabolism of zuclopenthixol include sulfoxidation, side-chain N-dealkylation, and glucuronic acid conjugation. It is mainly excreted in the faeces as unchanged drug and its N-dealkylated metabolite. Zuclopenthixol is about 98% bound to plasma proteins. It is widely distributed in the body and crosses the blood-brain barrier. Small amounts of drug or metabolites cross the placenta and are distributed into breast milk.
On intramuscular injection the acetate and decanoate esters of zuclopenthixol are hydrolysed to release zuclopenthixol. Zuclopenthixol acetate has a relatively quick onset of action after injection and a duration of action of 2 to 3 days. It is therefore useful for the control of acute psychotic symptoms while avoiding repeated injections. The decanoate has a much longer duration of action and is a suitable depot preparation for maintenance treatment.
Metabolism. Determination of metaboliser phenotype with regard to cytochrome P450 isoenzyme C YP2D6 appeared to be of limited value in patients receiving zuclopenthixol as interindividual variation appeared to be the main factor affecting dose to serum concentration ratios.
Uses and Administration
Zuclopenthixol is a thioxanthene of high potency with general properties similar to the phenothiazine, chlorpromazine. It has a piperazine side-chain. Zuclopenthixol is used for the treatment of schizophrenia (see below), mania (see Bipolar Disorder), and other psychoses. It may be particularly suitable for agitated or aggressive patients who may become overexcited with flupentixol. Zuclopenthixol hydrochloride is usually given orally with doses expressed in terms of the base zuclopenthixol hydrochloride 11.8 mg is equivalent to about 10 mg of zuclopenthixol. Zuclopenthixol hydrochloride has also been given intramuscularly. Zuclopenthixol acetate and zuclopenthixol decanoate are given by deep intramuscular injection doses are expressed in terms of the ester. The acetate ester has a rapid onset of action and a duration of action of 2 to 3 days it is used as a 5% oily solution for the initial treatment of acute psychoses and for exacerbations of chronic psychoses. The longer-acting decanoate ester is used as a 20% oily solution for the maintenance treatment of chronic psychoses a 50% solution is available for those requiring high doses.
• The usual initial oral dose of the hydrochloride for the treatment of psychoses is the equivalent of 20 to 30 mg of the base daily in divided doses in severe or resistant cases up to 150 mg daily has been given. The usual maintenance dose is 20 to 50 mg daily.
• The usual dose of zuclopenthixol acetate is 50 to 150 mg by deep intramuscular injection repeated, if necessary after 2 or 3 days. Some patients may need an additional injection between 1 and 2 days after the first dose.
Zuclopenthixol acetate is not intended for maintenance treatment no more than 4 injections should be given in a maximum course of 2 weeks and the total dose should not exceed 400 mg. When maintenance treatment is required, oral zuclopenthixol hydrochloride may be introduced 2 to 3 days after the last injection of zuclopenthixol acetate, or intramuscular injections of the decanoate (see below) begun with the last injection of the acetate.
• The long-acting decanoate should be given by deep intramuscular injection treatment is usually started with a test dose of 100 mg. This may be followed after at least 1 week by a dose of 200 to 500 mg or more, every 1 to 4 weeks, adjusted according to response. Injection volumes greater than 2 niL should be divided between 2 separate injection sites. The maximum recommended dose of zuclopenthixol decanoate is 600 mg weekly.
Elderly or debilitated patients should be given reduced doses of zuclopenthixol. Licensed product information states that the dose of the hydrochloride or the decanoate may need to be reduced to one-quarter or one-half of the usual initial dose in addition, the maximum single dose of the acetate should be limited to 100 mg.
Administration in hepatic or renal impairment. Licensed product information recommends that for zuclopenthixol acetate, half the normal recommended intramuscular dose should be used for patients with hepatic impairment a dosage reduction is considered to be unnecessary in patients with renal impairment but where there is renal failure half the normal intramuscular dosage is recommended.
Schizophrenia. A systematic review comparing zuclopenthixol decanoate with other depot antipsychotics considered that although it may induce more adverse effects, limited data suggested it might offer advantages such as lower relapse rates and increased acceptability in the treatment of schizophrenia and similar serious mental illnesses. Similar reviews of the use of the acetate or hydrochloride found, however, that evidence of additional benefit over other antipsychotics was lacking.
BP 2008: Zuclopenthixol Acetate Injection; Zuclopenthixol Decanoate Injection; Zuclopenthixol Tablets.
- Omeprazole Information for Consumers
- Omeprazole Information for Healthcare Professionals (includes dosage details)
- Side Effects of Omeprazole (detailed)
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