Like other benzodiazepines, diazepam can impair short-term memory and learning of new information. While benzodiazepine drugs such as diazepam can cause anterograde amnesia, they do not cause retrograde amnesia; information learned before using benzodiazepines is not impaired. Tolerance to the cognitively impairing effects of benzodiazepines does not tend to develop with long-term use, and the elderly are more sensitive to them. Additionally, after cessation of benzodiazepines, cognitive deficits may persist for at least six months; it is unclear whether these impairments take longer than six months to abate or if they are permanent. Benzodiazepines may also cause or worsen depression. Infusions or repeated intravenous injections of diazepam when managing seizures, for example, may lead to drug toxicity, including respiratory depression, sedation and hypotension. Drug tolerance may also develop to infusions of diazepam if it is given for longer than 24 hours. Sedatives and sleeping pills, including diazepam, have been associated with an increased risk of death.In September 2020, the U.S. Food and Drug Administration (FDA) required the boxed warning be updated for all benzodiazepine medicines to describe the risks of abuse, misuse, addiction, physical dependence, and withdrawal reactions consistently across all the medicines in the class.Diazepam has a range of side effects common to most benzodiazepines, including:

Suppression of REM sleep and Slow wave sleep
Impaired motor function
Impaired coordination
Impaired balance
Dizziness
Reflex tachycardiaLess commonly, paradoxical side effects can occur, including nervousness, irritability, excitement, worsening of seizures, insomnia, muscle cramps, changes in libido,  and in some cases, rage and violence.
Benzodiazepines have a relatively low toxicity in overdose.Diazepam has a number of uses including:

Treatment of anxiety, panic attacks, and states of agitation
Treatment of neurovegetative symptoms associated with vertigo
Treatment of the symptoms of alcohol, opiate, and benzodiazepine withdrawal
Short-term treatment of insomnia
Treatment of muscle spasms
Treatment of tetanus, together with other measures of intensive treatment
Adjunctive treatment of spastic muscular paresis (paraplegia/tetraplegia) caused by cerebral or spinal cord conditions such as stroke, multiple sclerosis, or spinal cord injury (long-term treatment is coupled with other rehabilitative measures)
Palliative treatment of stiff person syndrome
Pre- or postoperative sedation, anxiolysis or amnesia (e.g., before endoscopic or surgical procedures)
Treatment of complications with stimulant overdoses and psychosis, such as cocaine or methamphetamineUsed in treatment of organophosphate poisoning and reduces the risk of seizure induced brain and cardiac damage. Preventive treatment of oxygen toxicity during hyperbaric oxygen therapyDosages should be determined on an individual basis, depending on the condition being treated, severity of symptoms, patient body weight, and any other conditions the person may have. Seizures
Intravenous diazepam or lorazepam are first-line treatments for status epilepticus. However, intravenous lorazepam has advantages over intravenous diazepam, including a higher rate of terminating seizures and a more prolonged anticonvulsant effect. Diazepam gel was better than placebo gel in reducing the risk of non-cessation of seizures.