FENTANYL OVERDOSE SYMPTOMS AND DURATION SECRETS

fentanyl, cyproheptadine. Either will increase toxicity with the other by pharmacodynamic synergism. Modify Therapy/Watch Closely. Coadministration of fentanyl with anticholinergics may raise risk for urinary retention and/or serious constipation, which may bring about paralytic ileus.For oral drugs where reductions in bioavailability could cause c