Causes
Benzodiazepine is used as an anti-anxiety sedative because of its rapid inhibitory effect on nerve activity via gamma-aminobutyric acid (GABA) receptors in the central nervous system (CNS). Benzodiazepines provide relaxation and hypnotic effects therapeutically and can be misused to get high or to come down from the effects of stimulants. Benzodiazepine abuse may be acute (for example, illegal use or accidental overdose from prescription) or may be chronic (for example, repeatedly and deliberately combining with cocaine or alcohol to get high or to self-medicate during alcohol withdrawal). Also, chronic misuse of prescribed benzodiazepines by increasing the dose, duration, or number of prescriptions can result in drug dependency.
Although newer CNS agents for anxiety treatment, such as selective serotonin reuptake inhibitors, are available, benzodiazepines can be taken as needed for sporadic anxiety-inducing circumstances; they also act quickly to relieve acute anxiety. However, these two benefits can cause benzodiazepine abuse. The widespread availability of the drug eases accessibility for nonprescription users; for example, benzodiazepines have been used as date rape drugs, which impair function and, thus, resistance to sexual assault, especially because the drug is difficult to taste when dissolved in a drink.
Risk Factors
Although benzodiazepines have lower abuse potential than do older psychotropic drugs, opioids, and stimulants, benzodiazepines remain popular for abuse in combination. Benzodiazepines with rapid onset, such as diazepam, are the most likely to be abused, although short- or intermediate-acting agents, such as alprazolam or lorazepam, may be abused too. Longer-acting agents, such as clonazepam, are associated with fewer cases of rebound anxiety or abuse.
Longer duration of prescription use (more than four weeks) and higher prescribed dosages (greater content or multiple daily doses) both increase the risk of physical dependence and withdrawal symptoms upon drug discontinuation. As tolerance develops to the prescribed dosages, abusive self-medicating behaviors, such as increasing the number of pills or increasing the times a pill is taken without consulting a physician can occur.
Additional risk factors for abuse of a benzodiazepine prescription are combining controlled substance prescriptions, particularly prescribed drugs that have similar CNS activity, and having a history of legal or illegal drug abuse. For example, methadone users often combine diazepam with methadone to increase the effect of the latter drug.
Symptoms
Acute symptoms of benzodiazepine abuse or misuse are less likely to be fatal than benzodiazepine abuse in combination with alcohol. Prominent acute symptoms of abuse are mood changes, increased sleep with trouble awakening, unusual behaviors, and poor focus. With high doses, possible symptoms include confusion, blurred vision, dizziness, weakness, slurred speech, poor coordination, shallow breathing, and even coma.
Chronic symptoms of abuse are more difficult to identify; signs of addiction to a prescribed product include requests for increased doses to provide the same anxiety-relieving effects (drug tolerance) and the use of multiple prescriptions and doctors for the same drugs (drug-seeking behavior). Persons who abuse benzodiazepines chronically may have a changed appearance, changed behaviors, or changed mood, and they may regularly display poor performance at work or home. At times, these symptoms may mimic anxiety disorders themselves.
Long-term benzodiazepine use may lower cognition permanently, with only partial recovery of cognitive abilities upon discontinuation of the benzodiazepine. Seizure risk exists during withdrawal, especially with drugs (such as alprazolam) in the class that have short half-lives.
Screening and Diagnosis
With the exception of acute overdose presenting in an emergency room, screening for benzodiazepine abuse requires subtle observation by family and health care providers. Chronic abuse may lead users to stop performing their normal duties at home and work; abusers will increasingly neglect themselves and others. Abusers may take benzodiazepines even in unsafe circumstances, such as before driving a vehicle, and may experience legal or family problems. Repeated requests for prescriptions, early pharmacy refills, and hiding medications in different locations are signs of addiction and drug-seeking behavior.
Dependence may be identified as an aid to diagnosing benzodiazepine abuse. When benzodiazepines are used regularly for more than two to three weeks, even at low doses, they begin to lose their inhibitory GABA effects, and higher doses are required to relieve anxiety or to obtain a high. Once this tolerance develops, withdrawal symptoms upon drug discontinuation are also likely and may occur within days of stopping the benzodiazepine.
Withdrawal symptoms also may contribute to a diagnosis of abuse because they differ from rebound anxiety symptoms and appear more similar to the symptoms of alcohol withdrawal. Tremor, insomnia, sweating, and nausea and vomiting are possible. Sensitivity to light and sound are common and directly distinguish withdrawal from symptoms of an underlying anxiety disorder. More severe withdrawal symptoms include agitation, confusion, myoclonic jerks, and seizures.
Treatment and Therapy
Acute overdose treatment in an emergency room depends upon the amount of time passed since the benzodiazepine was ingested. Within one to two hours of a lethal dose, gastric lavage may be used to flush the stomach. Alternatively, one dose of activated charcoal can be given within four hours of ingestion to bind the drug in the stomach; severe cramps and nausea are possible, and vomiting is a risk. Flumazenil provides an antidote to the sedative effects of benzodiazepines in cases of severe overdose and coma risk; however, its use may cause seizures when given to people who abuse benzodiazepines chronically and who may have become dependent.
Chronic abuse treatment is multifactorial and gradual. A slow tapering of dosage is key to avoiding rebound anxiety or withdrawal symptoms, which may take three to four days after drug discontinuation to begin. At the physician’s discretion, a short-acting benzodiazepine such as triazolam may be replaced with longer-acting agents in the class, such as chlordiazepoxide (Librium), or with a prescription agent from another class with a similar mechanism, such as gabapentin (an antiseizure drug). Either replacement may be more safely tapered and stopped.
In some persons with chronic anxiety disorder, benzodiazepines cannot be fully discontinued. These persons may remain on very low dosages of the abused drug or another benzodiazepine, under strict observation, to avoid withdrawal and rebound risks and to minimize tolerance or abuse, which is likely with higher dosages, without sacrificing anti-anxiety therapy.
Prevention
The key to prevention of acute or chronic benzodiazepine abuse is to lower its availability in prescribed and nonprescribed forms. The drug should be replaced as a prescription with safer and newer anti-anxiety agents. Physical dependence and acute misuse are less likely to occur if longer-acting or alternatively acting agents are prescribed for short time periods with careful physician supervision.
Bibliography
“Drug Abuse and Addiction: Benzodiazepines.” Cleveland Clinic: Current Clinical Medicine. 2nd ed. Cleveland: Elsevier, 2010. Print.
Goldman, Lee, and Dennis Ausiello. “Drugs of Abuse: Benzodiazepines and Other Sedatives.” Cecil Medicine. Eds. Lee Goldman and Dennis Ausiello. 23rd ed. Philadelphia: Elsevier, 2007. Print.
Kaye, Alan David, Nalini Vadivelu, and Richard D. Urman, eds. Substance Abuse: Inpatient and Outpatient Management for Every Clinician. New York: Springer, 2015.
O’Brien, Charles P. “Benzodiazepine Use, Abuse, and Dependence.” Journal of Clinical Psychiatry 66 (2006): 28–33. Print.
Ruiz, Pedro, and Eric C. Strain. The Substance Abuse Handbook. Philadelphia: Wolters, 2014. Print.
United States. Department of Health and Human Serivces. Substance Abuse and Mental Health Services Administration. The DAWN Report: Benzodiazepones in Combination with Opioid Pain Relievers or Alcohol: Greater Risk of More Serious ED Visit Outcomes. Rockville: SAMHSA, 2014. PDF file.
No comments:
Post a Comment