Adverse events most frequently encountered in patients treated with quazepam are drowsiness and headache.

Accurate estimates of the incidence of adverse events associated with the use of any drug are difficult to obtain. Estimates are influenced by drug dose, detection technique, setting, physician judgments, etc. Consequently, the table below is presented solely to indicate the relative frequency of adverse events reported in representative controlled clinical studies conducted to evaluate the safety and efficacy of quazepam. The figures cited cannot be used to predict precisely the incidence of such events in the course of usual medical practice. These figures, also, cannot be compared with those obtained from other clinical studies involving related drug products and placebo.

The figures cited below are estimates of untoward clinical event incidences of 1% or greater among subjects who participated in the relatively short-duration, placebo-controlled clinical trials of quazepam.

The following incidences of laboratory abnormalities occurred at a rate of 1% or greater in patients receiving quazepam and the corresponding placebo group. None of these changes were considered to be of physiological significance.

The following additional events occurred among individuals receiving quazepam at doses equivalent to or greater than those recommended during its clinical testing and development. There is no way to establish whether or not the administration of DORAL® (quazepam tablets) caused these events.

Hypokinesia, ataxia, confusion, incoordination, hyperkinesia, speech disorder, and tremor were reported.

Also, depression, nervousness, agitation, amnesia, anorexia, anxiety, apathy, euphoria, impotence, decreased libido, paranoid reaction, nightmares, abnormal thinking, abnormal taste perception, abnormal vision, and cataract were reported.

Also reported were urinary incontinence, palpitations, nausea, constipation, diarrhea, abdominal pain, pruritus, rash, asthenia, and malaise.

The following list provides an overview of adverse experiences that have been reported and are considered to be reasonably related to the administration of benzodiazepines: incontinence, slurred speech, urinary retention, jaundice, dysarthria, dystonia, changes in libido, irritability, and menstrual irregularities.

As with all benzodiazepines, paradoxical reactions such as stimulation, agitation, increased muscle spasticity, sleep disturbances, hallucinations, and other adverse behavioral effects may occur in rare instances and in a random fashion. Should these occur, use of the drug should be discontinued.

There have been reports of withdrawal signs and symptoms of the type associated with withdrawal from CNS depressant drugs following the rapid decrease or the abrupt discontinuation of benzodiazepines (see Drug Abuse And Dependence).

Drug Abuse And Dependence

Controlled Substance

DORAL® (quazepam tablets) is a controlled substance under the Controlled Substances Act and has been assigned by the Drug Enforcement Administration to Schedule IV.

Abuse and Dependence

Abuse and addiction are separate and distinct from physical dependence and tolerance. Abuse is characterized by misuse of the drug for non-medical purposes, often in combination with other psychoactive substances. Physical dependence is a state of adaptation that is manifested by a specific withdrawal syndrome that can be produced by abrupt cessation, rapid dose reduction, decreasing blood level of the drug and/or administration of an antagonist. Tolerance is a state of adaptation in which exposure to a drug induces changes that result in a diminution of one or more of the drug's effects over time. Tolerance may occur to both the desired and undesired effects of drugs and may develop at different rates for different effects.

Addiction is a primary, chronic, neurobiological disease with genetic, psychosocial, and environmental factors influencing its development and manifestations. It is characterized by behaviors that include one or more of the following: impaired control over drug use, compulsive use, continued use despite harm, and craving. Drug addiction is a treatable disease, utilizing a multidisciplinary approach, but relapse is common.

Withdrawal symptoms, similar in character to those noted with barbiturates and alcohol (e.g., convulsions, tremor, abdominal and muscle cramps, vomiting, and sweating), have occurred following abrupt discontinuance of benzodiazepines. The more severe withdrawal symptoms have usually been limited to those patients who received excessive doses over an extended period of time. Generally milder withdrawal symptoms (e.g., dysphoria and insomnia) have been reported following abrupt discontinuance of benzodiazepines taken continuously at therapeutic levels for several months. Consequently, after extended therapy, abrupt discontinuation should generally be avoided and a gradual dosage tapering schedule followed. Addiction-prone individuals (such as drug addicts or alcoholics) should be under careful surveillance when receiving quazepam or other psychotropic agents because of the predisposition of such patients to habituation and dependence.

Read the Doral (quazepam tablets) Side Effects Center for a complete guide to possible side effects »

The benzodiazepines, including DORAL® (quazepam tablets) Tablets, produce additive CNS depressant effects when co-administered with psychotropic medications, anticonvulsants, antihistaminics, ethanol, and other drugs which produce CNS depression.

Quazepam is a mechanism based inhibitor of CYP2B6 based on an in vitro study. However, the in vivo extrapolation of this is unknown. It may be possible that co-administration of DORAL® (quazepam tablets) and drugs primarily metabolized by CYP2B6 (e.g., efavirenz and bupropion) may result in increased plasma concentrations of these drugs resulting in an increase in adverse events (e.g., CNS toxicities associated with efavirenz and precipitation of seizures with bupropion). Patients taking medications that are CYP2B6 substrates with DORAL® (quazepam tablets) should be monitored closely for adverse reactions associated with these medications. If adverse events are observed, clinicians may consider the discontinuation of DORAL® (quazepam tablets) and the selection of an alternative anxiolytic agent.

Last reviewed on RxList: 4/30/2010
This monograph has been modified to include the generic and brand name in many instances.