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.
In April 2014, U.S. House Democrats Henry Waxman, Frank Pallone Jr., and Diana DeGette wrote Gilead Sciences Inc. questioning the $84,000 price for sofosbuvir. They specifically asked Gilead CEO John Martin to "explain how the drug was priced, what discounts are being made available to low-income patients and government health programs, and the potential impact to public health by insurers blocking or delaying access to the medicine because of its cost." Sofosbuvir is cited as an example of how specialty drugs present both benefits and challenges. Sofosbuvir also is an excellent example of both the benefit and the challenge of specialty medications. On one hand, this agent offers up to a 95% response rate as part of an interferon-free treatment regimen for hepatitis C. Generally speaking, it is more effective and better tolerated than alternative treatments. Unfortunately, the current per pill cost—$1,000—results in an $84,000 treatment course, creating barriers to therapy for many. Patients, providers, and payors alike have expressed outrage, and the debate has even drawn the attention of the US Congress. Despite these concerns, sofosbuvir rapidly has become a top seller in the United States... In February 2015, Gilead announced that due in part to negotiated discounts with pharmacy benefit managers and legally mandated discounts to government payers, the average discount-to-list price in 2014 was 22%. The company estimated that the average discount in 2015 would be 46%.