Zopam Injection Drug Interactions

Alcohol or CNS depression-producing medications, other: Concurrent use may increase the CNS depressant effects of either these medications or benzodiazepines; caution is recommended and dosage of one or both agents should be reduced; when a benzodiazepine is used concurrently with an opioid analgesic, the dosage of the opioid analgesic should be reduced by at least one-third and administered in small increments.
Antacids: Concurrent use may delay, but not reduce, the absorption of diazepam.
Antiepileptics: Carbamazepine, phenobarbitone, and phenytoin are all inducers of hepatic drug-metabolising enzymes. Therefore, in patients receiving long-term therapy with these drugs the metabolism of benzodiazepines may be enhanced.
Cimetidine or Contraceptives, estrogen-containing, oral or Disulfiram or Erythromycin: Concurrent use may inhibit the hepatic metabolism of benzodiazepines that are metabolised by oxidation, especially diazepam, resulting in delayed elimination and increased plasma concentrations.
Clozapine: Collapse, sometimes accompanied by respiratory depression or arrest, has been reported in a few patients receiving clozapine concurrently with benzodiazepines. Caution is advised when clozapine is administered concomitantly with any agent that may depress respiration, and the dosage of clozapine should be titrated upwards slowly. Some clinicians have recommended that benzodiazepines be discontinued at least 1 week prior to initiation of therapy with clozapine.
Fentanyl derivatives: Premedication with diazepam may decrease the dose of a fentanyl derivative required for induction of anesthesia and decrease the time of loss of consciousness with induction doses; also, administration of diazepam prior to or during surgery may decrease risk of patient recall of surgical events post-operatively; however, these potential benefits must be weighed against the potential risks of concurrent use, such as increased risk of' severe hypotension and respiratory depression, and delayed recovery time, especially when the benzodiazepine is administered intravenously.
Hypotension-producing medications, other: Concurrent use may potentiate the hypotensive effects of benzodiazepine preanesthetics used in surgery; dosage adjustments may be necessary. Concurrent use of mecamylamine or trimethaphan may potentiate the hypotensive response, with increased risk of severe hypotension, shock, and cardiovascular collapse during surgery. Caution is advised during titration of calcium channel blocker dosage for those patients taking benzodiazepine preanesthetics, since the combination may result in excessive hypotension.
Isoniazid: Concurrent use may inhibit the elimination of diazepam, resulting in increased plasma concentrations; dosage adjustment may be necessary.
Ketamine: Premedication with diazepam prolongs the half-life of ketamine, resulting in an enhanced effect.
Levodopa: Concurrent use with benzodiazepines may decrease the therapeutic effects of levodopa.
Omeprazole: Concurrent use of omeprazole may prolong the elimination of diazepam.
Rifampin: Concurrent use may enhance the elimination of diazepam, resulting in decreased plasma concentrations; dosage adjustment may be necessary.
Sodium valproate: Sodium valproate has been reported to displace diazepam from plasma-protein binding sites.
Theophylline: Theophylline counteracts with the sedative and psychomotor effects of diazepam.
Xanthines: There are reports of aminophylline given intravenously reversing the sedation from intravenous diazepam. Theophylline also counteracts the sedative and psychomotor effects of diazepam.
Benzodiazepines: Due to additive pharmacologic effect, the concomitant use of opioids with benzodiazepines increases the risk of respiratory depression, profound sedation, coma and death.
The concomitant use of opioids and benzodiazepines increases the risk of respiratory depression because of actions at different receptors sites in the central nervous system that control respiration. Opioids interact primarily at μ-receptors, and benzodiazepines interact at GABA_A sites. When opioids and benzodiazepines are combined, the potential for benzodiazepines to significantly worsen opioid-related respiratory depression exists.
Reserve concomitant prescribing of these drugs for use in patients for whom alternative treatment options are inadequate (see Precautions).
Limit dosage and duration of concomitant use of benzodiazepines and opioids, and follow patients closely for respiratory depression and sedation.