Neurologic changes. Chronic methamphetamine use is characterized by poor cognitive functioning and emotional changes such as paranoia and depression.29 These are believed to be caused by neuropathologic changes in the cortex, striatum, and hippocampus.
Table 4
Medical complications of methamphetamine abuse
Cardiovascular: Arrhythmias; hypertensive crisis; myocardial infarction; cardiomyopathy; tachycardia |
Pulmonary: Pneumomediastinum respiratory failure |
Gastrointestinal: Tooth decay (‘Meth mouth’); xerostomia; bruxism; hepatitis infection; hepatotoxicity |
Neurologic: Cerebral infarct; seizures; blurred vision; obtundation |
Other: Jaw clenching; excessive sweating; aplastic anemia; hyperthermia; muscle cramping |
Opioids
Prescriptions of opioid analgesics for chronic pain—and their subsequent diversion—are the main conduit to nonmedical use.30 IV heroin use is the most common cause of illicit drug overdose.31 Opioids are used by:
- ingestion, usually of synthetic analgesics (prescription drugs)
- parenteral administration, often IV heroin
- inhalation, a pure form that is heated and burned.
Infectious complications. Injection drug use—especially with unsterilized shared needles—is an efficient vector for blood-borne infections. Needle sharing is the most common cause of new HIV and viral hepatitis infections.32 All IV drug users should be routinely tested for these viral infections. Chronic IV drug use can cause vein sclerosis, leading to visible “track marks” and, rarely, thromboembolic events. Be alert for integumentary infections—especially in patients who “skin pop” drugs by injecting them under the skin—or systemic infectious diseases, such as skin abscesses, cellulitis, septicemia, botulism, or bacterial endocarditis (Table 5).33
Pulmonary complications. Overstimulation of opioid receptors in the brainstem and carotid bodies can cause slow and irregular respiration and decreased gag and coughing reflex during acute intoxication. The rate of opioid intake appears to play a role; a gradual increase in opioid blood levels leads to progressive respiratory depression by causing gradual hypercapnia, and a quick rise in receptor occupancy can lead to rapid apnea. Therefore opioids with slow receptor binding, such as buprenorphine, may be safer than those that bind more quickly, such as fentanyl. However, all opioids can cause this dangerous side effect.34 Inhaled forms of heroin have also been shown to lead to status asthmaticus.35
Table 5
Medical complications of opioid abuse
Cardiovascular: Prolonged QTc interval (methadone) |
Pulmonary: Respiratory suppression |
Gastrointestinal: Hepatitis C infection; hepatotoxicity; nausea; constipation |
Neurologic: Drowsiness; lightheadedness; confusion; myoclonus; hyperalgesia; miosis |
Other: Urinary retention; pruritus |
Cardiac and neurologic complications. Methadone use could prolong the QTc interval, leading to dysrhythmias such as torsades de pointes. Higher doses increase the incidence of syncope.36 Ongoing monitoring of the QTc interval is warranted for all patients on methadone.
Neurologic effects of opioids include:
- delayed leukoencephalopathy with IV overdose and inhaled preheated heroin, known as ”chasing the dragon”
- widespread cortical dysfunction (abulia, lack of volition, hemineglect,37 and deficits in executive functioning and emotional processing) leading to impaired decision-making.38
Related resources
- National Institute on Drug Abuse. www.nida.nih.gov.
- Substance Abuse and Mental Health Services Administration. www.samhsa.gov.
- National Institute on Alcohol Abuse and Alcoholism. www.niaaa.nih.gov.
- Johnston LD, O’Malley PM, Bachman JG, et al. Monitoring the Future national survey results on drug use, 1975-2008. Volume I: Secondary school students. Bethesda, MD: National Institute on Drug Abuse; 2009. NIH Publication No. 09-7402.
Drug brand names
- Buprenorphine • Subutex
- Fentanyl • Actiq, Duragesic, others
- Methadone • Dolophine, Methadose
Disclosures
Drs. Khan and Morrow report no financial relationship with any company whose products are mentioned in this article or with manufacturers of competing products.
Dr. McCarron is a consultant to Eli Lilly and Company.