National Drug Strategy
National Drug Strategy

Comorbidity of mental disorders and substance use: a brief guide for the primary care clinician

3.5 Benzodiazepines

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Diazepam, temazepam, oxazepam, nitrazapam, alprazolam, flunitrazepam, lorazepam, clonazepam, midazolam

Benzodiazepines are sedative drugs that may be prescribed to reduce symptoms associated with anxiety, encourage sleep or act as a muscle relaxant. Both prescribed and non-prescribed use of these medications is extremely common. Short-acting or rapidly-absorbed varieties (for example, alprazolam) produce a more immediate feeling of intoxication, are the most sought after by doctor shoppers and can be sold or exchanged on the street.

Benzodiazepines are often used in combination with alcohol, other benzodiazepines or other illicit drugs. Dependence may occur when benzodiazepines are taken in an attempt to medicate (self-medicate) symptoms that are associated with an undiagnosed mental disorder such as anxiety.

Effects sought by user: Euphoria, anxiolysis, skeletal muscle relaxation and sedation.

Associated harms: Drowsiness, confusion, disinhibition, impaired coordination and increased driving risk, light and sound sensitivity, forgetfulness or memory impairment, nausea, depression, digestive problems, tachycardia, apnoea, ataxia, hypotension and seizures.

When injected intravenously vein damage is common along with those harms associated with injecting drug use mentioned earlier. Problems associated with injecting drug use include: scarred or collapsed veins, abscesses, bacterial infections, blood borne viruses (e.g. hepatitis B and C, Human Immunodeficiency Virus [HIV]), thrombophlebitis, intravascular sepsis, endocarditis, accidental arterial injection and peripheral ischaemia.

When accidentally injected arterially, benzodiazepines can result in peripheral ischaemia and gangrene.

Overdose: Risk is variable depending on the strength of particular formulations. However, taken in large amounts and/or in-conjunction with other benzodiazepines or other substances (usually alcohol), there is a high risk of overdose, particularly in people with a high suicide risk. Overdose results in prolonged periods of sleep combined with respiratory and cardiovascular depression which can be fatal when combined with alcohol.

Withdrawal: There is an established withdrawal effect associated with the use of benzodiazepines. Likelihood of withdrawal is higher for stronger, shorter-acting types that are used for a long period of time. Withdrawal effects include anxiety, depression, problems with sleeping, irritability, palpitations and sensory disturbances. Seizures can occur with sudden withdrawal from more than 40mg/day of diazepam or diazepam equivalents.

Psychological presentations commonly associated with use (likely to resolve on cessation of substance use): Depression and rebound anxiety(57-59).

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