The effects seen with flunitrazepam are those seen with other benzodiazepines. Most adverse effects associated with the benzodiazepines are related to their ability to produce central nervous system depression. Other CNS effects include blurred vision, hallucinations, and paradoxical reactions consisting of excitement, stimulation, and hyperactivity. Illicit use of flunitrazepam exploits these effects in that in combination with alcohol they are enhanced. As with any CNS depressant, depression of the respiratory drive is a possible effect with adequate dosages.
Potentiation occurs with nitrous oxide, fentanyl, ketamine, and possibly other opioids.
Drug interactions include increased blood levels of imipramine and desipramine in patients receiving benzodiazepines. Erythromycin may increase blood levels of benzodiazepines. Cimetidine coadministered with diazepam has resulted in an increased half-life of both diazepam and its desmethyl derivative. Tolerance and dependence do occur with the use of benzodiazepines. Discontinuation of drug administration, particularly an abrupt withdrawal, can be associated with a variety of symptoms including headaches, muscle pain, extreme anxiety, tension, restlessness, confusion, and irritability.