How should you treat anxiety in substance-abusing patients: deny them benzodiazepines and risk under-treatment, or prescribe benzodiazepines for the anxiolytic effect and risk contributing to addiction?
There is no definitive answer, but one thing is clear: Among psychiatric patients, substance abusers are most likely to abuse benzodiazepines and become addicted to them.
Some argue that the abuse potential is overstated, but only limited data suggest that benzodiazepines can be safely prescribed to patients who are abusing alcohol or drugs. In this article, we discuss benzodiazepine use in these patients and offer a sobriety-based treatment approach.
Table 1
Benzodiazepines’ potency and half-lives, including half-lives of active metabolites
| Potency | Shorter half-life (hr) | Longer half-life (hr) |
|---|---|---|
| High | Alprazolam (6 to 12) Lorazepam (10 to 20) Triazolam (2) | Clonazepam (18 to 50) |
| Low | Oxazepam (4 to 15) Temazepam (8 to 22) | Chlordiazepoxide (5 to 30) [36 to 200]* Clorazepate [36 to 200]* Diazepam (20 to 100) [36 to 200]* Flurazepam [40 to 250]* |
| * [active metabolite] | ||
| Source: Ashton CH. Benzodiazepine equivalence table. Available at www.benzo.org.uk | ||
BENEFITS AND RISKS
Considered a safe substitute for barbiturates, benzodiazepines were heralded as wonder drugs when they were introduced in the 1950s. Reports of their addictive potential surfaced in the 1970s, and since then researchers have disagreed on whether benzodiazepines should be prescribed to substance-abusing or -dependent patients.
Clinical utility. Benzodiazepines are used in many clinical situations because of their:
- anxiolytic, hypnotic, anticonvulsant, antipanic, antidepressant, amnestic, anesthetic, and antispastic effects
- relatively mild side effects, when compared with alternatives such as barbiturates.
In psychiatry, benzodiazepines are used to treat anxiety disorders, agitation, and insomnia. Because of cross-tolerance with alcohol and barbiturates, benzodiazepines also are used to manage alcohol or barbiturate withdrawal.
Interactions. Benzodiazepines can interact with other psychotropics, including lithium, antipsychotics, and selective serotonin reuptake inhibitors (SSRIs). Respiratory arrest has been reported in patients taking both a high-potency benzodiazepine and clozapine.1
Overdose and withdrawal symptoms. Benzodiazepine overdose is characterized by slurred speech, sedation, memory impairment, incoordination, respiratory depression, hypotension, stupor, and coma. Abrupt withdrawal may produce life-threatening delirium, hallucinations, grand mal seizures, and symptoms similar to those of alcohol withdrawal (insomnia, anxiety, tremor, hyperactivity, nausea, vomiting, and psychomotor agitation).1
ABUSE PATTERNS
The few empiric studies examining benzodiazepines’ abuse potential in substance abusers have shown inconsistent results. However, it is generally accepted that:
- long-term benzodiazepine use may lead to tolerance and physiologic dependence
- withdrawal symptoms can occur if benzodiazepines are stopped suddenly, especially after long-term (months to years) use.
Even though most benzodiazepine prescriptions are not abused,2 a history of alcohol and drug abuse suggests high potential for benzodiazepine abuse. Also, long-term users of prescribed benzodiazepines often develop tolerance and may escalate their doses to get the same desired effects. If their supply is threatened, these patients may seek benzodiazepines illicitly.
Benzodiazepines may enhance or prolong the elation (“high”) associated with other drugs or mitigate the depression (“crash”) that follows a stimulant “high.” Sometimes benzodiazepines are the drug of choice, as high doses of potent, short-acting agents may provide a stimulant “high.”
WHO ABUSES BENZODIAZEPINES?
Alcohol and substance abusers tend to ingest benzodiazepines for recreational purposes. Thirty to 50% of alcoholics undergoing detoxification and 44% of IV drug abusers also may be abusing benzodiazepines.3
Benzodiazepines are cross-tolerant with alcohol, and alcoholics may use them with alcohol or as a substitute when alcohol is unavailable. They also may self-medicate with benzodiazepines to ease alcohol’s withdrawal symptoms. Opiate, amphetamine, and cocaine abusers may use benzodiazepines with their drugs of choice, as may younger abusers of MDMA (“Ecstasy”) and LSD.
Even patients who begin taking benzodiazepines for legitimate reasons may end up abusing them. In one study of 2,600 patients prescribed diazepam, up to 60% had abused and/or become dependent on it.4
Benzodiazepine abuse may start with other sedative/hypnotic abuse or as experimentation with drugs or alcohol, typically around age 13 or 14.5 The average benzodiazepine abuser is age 19 to 31, and the male-to-female ratio is about 2:1.6
Multi-drug abuse. Benzodiazepines are usually not the preferred or sole drug of abuse. Roughly 80% of benzodiazepine abuse may be a component of poly-drug abuse, most commonly with opioid addiction.7 A 2-year National Institute on Drug Abuse study of heroin abusers suggested that 15% also abused benzodiazepines daily for more than 1 year, and 73% had abused benzodiazepines several times during the previous week.8 Other studies suggest that up to 90% of methadone users regularly abuse benzodiazepines, often at high doses.9
Table 2
Should benzodiazepines be prescribed to substance abusers?
YES: Arguments for
|
NO: Arguments against
|