Drug Interactions between cimetidine and Dilaudid Cough Syrup

GENERALLY AVOID: Alcohol may potentiate the central nervous system (CNS) depressant effects of opioid analgesics including hydromorphone. Concomitant use may result in additive CNS depression and impairment of judgment, thinking, and psychomotor skills. In more severe cases, hypotension, respiratory depression, profound sedation, coma, or even death may occur.

GENERALLY AVOID: Consumption of alcohol while taking sustained-release formulations of hydromorphone may cause rapid release of the drug, resulting in high systemic levels of hydromorphone that may be potentially lethal even in opioid-tolerant patients. Alcohol appears to disrupt the extended release mechanism, causing 'dose-dumping' into the bloodstream. In 48 healthy volunteers, coadministration of a 12 mg dose of sustained-release hydromorphone with 240 mL of 40% (80 proof) alcohol resulted in a mean peak hydromorphone concentration (Cmax) approximately six times greater than when taken with water. One subject had a 16-fold increase in hydromorphone Cmax with 40% alcohol compared to water. In some subjects, coadministration with 8 ounces of 4% alcohol (equivalent to 2/3 of a typical serving of beer) resulted in almost twice the hydromorphone Cmax than when coadministered with water. The effect of alcohol was more pronounced in a fasted state.

MANAGEMENT: Patients taking sustained-release formulations of hydromorphone should not consume alcohol or use medications that contain alcohol on days of hydromorphone dosing. In general, potent narcotics such as hydromorphone should not be combined with alcohol.

Concurrent use of cimetidine and ethanol may result in increased ethanol concentrations. The mechanism appears to be due to inhibition of gastric alcohol dehydrogenase by cimetidine, leading to increased bioavailability of the alcohol and inhibition of hepatic metabolism of alcohol. The clinical significance of this interaction is limited. More importantly, patients requiring cimetidine for gastrointestinal disease should be counseled to avoid alcohol to prevent worsening of their disease. The other H-2 receptor antagonists appear to have minimal effects on the concentrations of alcohol.

Caffeine effects may be increased in patients also taking cimetidine. The mechanism may be due to decreased caffeine metabolism induced by cimetidine. Although adequate clinical data are lacking, a reduction in dose or elimination of caffeine may be needed if excess CNS stimulation is observed.

H2 antagonists may reduce the clearance of nicotine. Cimetidine, 600 mg given twice a day for two days, reduced clearance of an intravenous nicotine dose by 30%. Ranitidine, 300 mg given twice a day for two days, reduced clearance by 10%. The clinical significance of this interaction is not known. Patients should be monitored for increased nicotine effects when using the patches or gum for smoking cessation and dosage adjustments should be made as appropriate.