At higher doses it may result in slurred speech, staggering gait, poor judgment, and slow, uncertain reflexes. Doses of sedatives such as benzodiazepines when used as a hypnotic to induce sleep tend to be higher than those used to relieve anxiety where as only low doses are needed to provide calming sedative effects.
Sedatives can be abused to produce an overly-calming effect (alcohol being the classic and most common sedating drug). At high doses or when they are abused, many of these drugs can cause unconsciousness (see hypnotic) and even death.
There is some overlap between the terms "sedative" and hypnotic. Although the effects described by the two terms are different, the medications that cause the effects described by one term often also cause the effects described by the other term.
The term "sedative-hypnotic" has been used to describe these joint effects, or the medications causing these joint effects. MeSH classifies these agents in a single category, under CNS depressants.
However, advances in pharmacology have permitted more specific targeting of receptors, and greater selectivity of agents, which necessitates greater precision when describing these agents and their effects:
Doctors and nurses often administer sedatives to patients in order to dull the patient's anxiety related to painful or anxiety-provoking procedures. Although sedatives do not relieve pain in themselves, they can be a useful adjunct to analgesics in preparing patients for surgery, and are commonly given to patients before they are anaesthetized, or before other highly uncomfortable and invasive procedures like cardiac catheterization , colonoscopy or MRI. They increase tractability and compliance of children or troublesome or demanding patients.
Patients in intensive care units are almost always sedated (unless they are unconscious from their condition anyway)
All Sedatives can cause physiological and psychological dependence when taken regularly over a period of time, even at therapeutic doses.    Dependent users may get withdrawal symptoms ranging from restlessness, insomnia to convulsions and death. When users become psychologically dependent, they feel as if they need the drug to function, although there is no physical dependence. In both types of dependences, finding and using the sedative becomes the focus in life. Both physical and psychological dependence can be treated with therapy. (see Sedative Dependence).
See also: Drug overdose.
See also: Combined Drug Intoxication.
See also: Benzodiazepine overdose.
All sedatives can be misused and abused, but barbiturates and benzodiazepines are responsible for most of the problems with sedative abuse due to their widespread "recreational" or non-medical use. People who have difficulty dealing with stress, anxiety or sleeplessness may overuse or become dependent on sedatives. Heroin users take them either to supplement their drug or to substitute for it. Stimulant users frequently take sedatives to calm excessive jitteriness. Others take sedatives recreationally to relax and forget their worries. Barbiturate overdose is a factor in nearly one-third of all reported drug-related deaths. These include suicides and accidental drug poisonings. Accidental deaths sometimes occur when a drowsy, confused user repeats doses, or when sedatives are taken with alcohol. In the U.S., in 1998, a total of 70,982 sedative exposures were reported to U.S. poison control centers, of which 2310 (3.2%) resulted in major toxicity and 89 (0.1%) resulted in death. About half of all the people admitted to emergency rooms in the U.S. as a result of nonmedical use of sedatives have a legitimate prescription for the drug, but have taken an excessive dose or combined it with alcohol or other drugs.
There are also serious paradoxical complications that may occur in conjunction with the use of sedatives that to some individuals result in results that are unexpected and the opposite to the effects expected. Malcolm Lader at the Institute of Psychiatry in London estimates the incidence of these adverse reactions at about 5%, even in short-term use of the drugs. The paradoxical reactions may consist of depression, with or without suicidal tendencies, phobias, aggressiveness, violent behavior and symptoms sometimes misdiagnosed as psychosis.
See also: Combined Drug Intoxication. Sedatives and alcohol are sometimes combined recreationally or carelessly. Since alcohol is a strong depressant that slows brain function and depresses respiration, the two substances compound each other's actions synergistically and this combination can prove fatal.
Lookalikes, or pills made to mimic the appearance and the effects of authentic sedatives, are sold on the street. Lookalikes may contain over-the-counter drugs, such as antihistamines, that cause drowsiness. Since the actual composition is unknown, neither the intensity of the primary effect nor the range of side effects can be predicted.
Sedation can sometimes leave the patient with long-term or short-term amnesia. Lorazepam is one such pharmacological agent that can cause anterograde amnesia. Intensive care unit patients who receive higher doses over longer periods of time, typically via IV drip, are more likely to experience such side effects.
Sedatives - most commonly alcohol but also GHB, Flunitrazepam (Rohypnol), and to a lesser extent, temazepam (Restoril), and midazolam (Versed) - are well known for their use as date rape drugs (also called a Mickey) and being administered to unsuspecting patrons in bars or guests at parties to reduce the intended victims' defenses. These drugs are also used for robbing people. Indeed statistical overviews suggest that the use of sedative-spiked drinks for robbing people is actually much more common than their use for rape. Cases of criminals taking rohypnol themselves before they commit crimes have also been reported, as the loss of inhibitions from the drug may increase their confidence to commit the offence, and the amnesia produced by the drug makes it difficult for police to interrogate them if they are caught.