Clozapine

Clozapine is antipsychotic drug. Clozapine is used to treat symptoms of Schizophrenia that are not treated by other drugs. It has been associated with bone marrow depression and is used only if hematological monirtoring is arranged.


Adult Dose
Dose: 12.5 mg
Single Dose: 12 (12.5)
Frequency: As recommended.
Route: PO
Instructions: Once or twice on day 1.
Neonatal
Dose:
Single Dose:
Frequency:
Route:
Instructions: Not recommended in this age group
Paedriatic
Dose:
Single Dose:
Frequency:
Route:
Instructions: Not recommended in this age group
Characteristics
. It is of Synthetic origin and belongs to Diazepine. It belongs to D2 antagonist pharmacological group on the basis of mechanism of action and also classified in Psychotherapeutic Drugs pharmacological group.The Molecular Weight of Clozapine is 326.80.
Contraindications
Clozapine is contraindicated in conditions like Cardiac failure,Renal failure,Coma,Hepatic failure,Hypersensitivity,CNS depression,Myeloproliferative disorders,Uncontrolled epilepsy.
Effects
The severe or irreversible adverse effects of Clozapine, which give rise to further complications include Bronchospasm, Orthostatic hypotension, Eosinophilia, Seizures, Neuroleptic malignant syndrome, Toxic delirium.Clozapine produces potentially life-threatening effects which include Agranulocytosis. which are responsible for the discontinuation of Clozapine therapy.The signs and symptoms that are produced after the acute overdosage of Clozapine include Hypotension, Cardiac arrhythmias, Convulsions, Coma, Respiratory depression, Hallucinations, Collapse, Delirium, Respiratory depression, Mydriasis, Lethargy, Extrapyramidal effects, Cardiac failure.The symptomatic adverse reactions produced by Clozapine are more or less tolerable and if they become severe, they can be treated symptomatically, these include Dizziness, Vertigo, Headache, Drowsiness, Fatigue, Constipation, Dry mouth, Blurred vision, Sedation, Syncope, Influenza like syndrome, Hypersalivation, Agitation, Xerostomia.
Indications
Clozapine is primarily indicated in conditions like Bipolar disorders, Pituitary diabetes insipidus, Schizophrenia, Schizophrenia and other psychoses, Tremor, and can also be given in adjunctive therapy as an alternative drug of choice in Extrapyramidal disorders, Refractory psychoses.
Interactions
Clozapine is known to interact with other drugs, the details of drug interactions is as follows:DrugDetailsSeverityOnsetManagementAlcoholAlprazolamApomorphineEffects of apomorphine antagonized by antipsychotics (e.g Clozapine).BleomycinADVICE: Avoid concomitant use of cytotoxics (e.g Bleomycin) with Clozapine (increased risk of agranulocytosis).BusulphanADVICE: Avoid concomitant use of cytotoxics with Clozapine. (increased risk of agranulocytosis).MajorCabergolineHypoprolactinemic and antiparkinsonian effects of Cabergoline possibly antagonized by antipsychotics (e.g Clozapine).CarbamazepineCarbamazepine reduces plasma concentration and decrease pharmacological effect of clozapine by induction of CYP450 hepatic metabolism.ModerateMonitor patient response and serum clozapine level.ChloramphenicolClozapine due to additive effect increase the risk of hematologic toxicity result in severe agranulocytosis when given with chloramphenicol.MajorThis combination shoud not be use.Cimetidine (HCl)CiprofloxacinCoadministration increases the plasma concentration of clozapine by inhibiting CYP450 1A2 responsible for metabolic clearance of clozapine.ModeratePharmacological response and plasma clozapine concentration should be monitored closely.Clorazepate (K)CyclophosphamideBoth agents act additively thus increases the risk and severity of hematologic toxicityMajorCoadministration is considered contraindicated.DiazepamBoth agents have additive effects on respirstory and cardiovascular system.MajorClosely monitor for vital signs.ErythromycinErythromycin decreases the hepatic clearence of clozapine thus increases the risk of toxicity.ModerateClosely monitor the patient whenever erythromycin added or withdraw from therapy. Azithromycin and dirithromycin is considered more safer alternative of erythromycin. Fluoxetine (HCl)Fluoxetin increases the srum level of clozapine upto 76% by inhibiting its hepatic metabolism.ModerateDose of clozapine should be reduced if necessary.Close clinical monitoring is advised.FluspirileneInfrequent reports of FLUSPIRILENE increasing the NEUTROPENIC effect of CLOZAPINE. Potential risk. May need to avoid combinationFluvoxamine (Maleate)Fluvoxamine increases the serum level of clozapine by inhibiting its metabolism results in increased toxicity.ModerateAdjust the dose if necessary. Closely monitor for altered efficacy and safety.GuanethidineHaloperidolHaloperidol exacerbate the adverse effect of clozapine on cardiovascular system.MajorCloely monitor the vital signs. patient should notify to physician if experience symptoms of anticholinergic intoxication. Dose of both drugs should reduce if necessary.IpriflavoneLisurideLithiumBoth agents act as additive serotonergic result in the development of neurologic toxicity.ModerateClosely monitor for neurologic symptoms and check the level of blood glucose regularly.LoprazolamLikely interaction of LOPRAZOLAM increasing the CNS TOXICITY of CLOZAPINE. ModerateMay need to avoid combination.MethimazoleBoth drugs act synergistically result in acute granulocytopenia.MajorClosely monitor for granulocytopenia.Metoclopramide (HCl)Noradrenaline (Acid Tartrate)ParoxetineParoxetin inhibit the hepatic metabolism of clozapine thus reduces its serum level result in increased toxicity.ModerateClosely monitor the patient for altered efficacy and safety. Adjust dose if necessary.PenicillaminePentostatinThe use of clozapine with other potentially myelotoxic agents may increase the risk and severity of hematologic toxicity due to additive pharmacodynamic effectsMajorClozapine should not be used concomitantly with other agents having a well-known potential to cause agranulocytosis or otherwise suppress bone marrow function.Phenylbutazone Both agents acts additively thus enhances the risk and severity of hematologic toxicityMajorThis combination should be avaoided due to increased risk of agranulocytosis and bone marrow suppression.Phenytoin (Na)Phenytoin reduces the plasma concentration of clozapine by inducing its hepatic metabolism.ModerateClosely monitor the altered effect of clozapine especially when start, change or discontinue hydantoin.PioglitazonePiribedilClozapine reduce the effect of piribedil.RisperidoneRitonavirRitonavir decreases the plasma concentration of clozapine by enhances its hepatic metabolism.MinorDose of clozapine should be adjusted accordingly.RituximabThe use of clozapine with other potentially myelotoxic agents may increase the risk and severity of hematologic toxicity due to additive pharmacodynamic effects. Clozapine alone may cause agranulocytosis, and the risk may theoretically increase when coadministered with other myelotoxic therapy.MajorClozapine should not be used concomitantly with other agents having a well-known potential to cause agranulocytosis or otherwise suppress bone marrow function.Sertraline (HCl)Sertraline enhances the serum level of clozapine by inhibiting its hepatic metabolism result in increased toxicity.ModerateClosely monitor for change in efficacy and safety. Adjust dose if ecessary.SulfapyridineConcurrent use of sulfapyridine with bone marrow depressants may increase the leukopenic or thrombocytopenic effects of these medications.If concurrent use is required, close observation for myelotoxic effects should be considered.SulphamethoxazoleTrimethoprimWarfarin (Na) These interactions are sometimes beneficial and sometimes may pose threats to life. Always consult your physician for the change of dose regimen or an alternative drug of choice that may strictly be required.
Interfrence
WBC count monitoring test
Risks
Drug should not be given to Paediatrics, Pregnant Mothers, Geriatrics, and Neonates.If prescribing authority justifies the benefits of the drug against the possible damages he/she should reevaluate them and consult the reference material and previous studies.
Storage
Tab Store Below 40°C. Protect from Sunlight and Moisture.
Warnings
Clozapine should be used with caution in patients with history of glaucoma, seizure disorders, enlarged prostate or blood disorder, blood vessel disease, kidney or liver disease and in cardiovascular disorders because clozapine is likely to induce tachycardia and/ orthostatic hypotension, Such patients should be treated with low initial dose, followed by a more gradual dosage titration and they should be warned of the possible side effects. Do not allow anyone else to take this medication. It should be used with extreme caution during pregnancy. Avoid clozapine during lactation.
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