Anesthesia Considerations for Patients Using Methamphetamine
As recreational drug use and substance use disorder (SUD) rise, and as the current state of the world continues to favor this rise, the issue of screening and proper treatment of patients with substance use disorders comes to the forefront of medicine 4. Behind marijuana, methamphetamine is the most common illicit drug of choice worldwide 2. Methamphetamines work on the dopaminergic and serotonergic pathways in the brain to induce, in small doses, its therapeutic effects: arousal, reduced fatigue, positive mood, and short-term improvement in cognition and focus. However, in larger doses, methamphetamine can lead to anxiety and paranoia, aggression, hypertensive and hypotensive states, psychotic symptoms 2, and various cardiovascular effects such as arrhythmias, aortic dissection, and acute coronary syndrome 5. Given the state of substance abuse and the surging rates attributed to the COVID-19 pandemic 4, it is becoming increasingly likely that health professionals, including anesthesia providers, will encounter patients who use methamphetamine and the myriad of complications with which they can present.
These patients may pose a significant challenge in the field of anesthesia. There are specific considerations that have been outlined in the overall management of patients with acute methamphetamine intoxication 1,4. A downstream effect of acute methamphetamine intoxication is the surge of catecholamines that act on receptive tissues to produce some of its effects. Catecholamines are mediators of the cardiovascular system: when levels are high, patients present with hypertension. After use, catecholamines can become depleted, making patients hypotensive 1,5. It is important to either reduce catecholamine depletion or restore patients to a normotensive state. Benzodiazepine and vasopressors (epinephrine, norepinephrine) are recommended in this case. Beta-blockers for hypertension are currently contraindicated with acute intoxication due to the possibility of coronary spasm1.
Benzodiazepines have other many therapeutic uses in the case of acute methamphetamine intoxication. They are recommended preoperatively in the setting of sedation or restraint of patients experiencing unrelated or use-related paranoia, aggression, or psychosis1,4. In these cases, physical restraint is generally contraindicated due to the increased cardiovascular stress of methamphetamine intoxication. Benzodiazepines also act to antagonize the effects of dopamine activity in the brain, which can help to dampen the effects of the drug in the short-term1.
Methamphetamine use also carries the risk of developing rhabdomyolysis, an illness involving the death of muscle fibers and the harmful release of cellular content into circulation 3. This complication is thought to be precipitated by a number of factors, namely, decreased fluid intake, diffuse vasoconstriction from decreased cardiac output, and the toxic effects of methamphetamines on the muscle itself. This complication is an indication for intraoperative fluid bolus and close monitoring for metabolic acidosis 3,4. Unchecked, this complication can advance to kidney failure and death 4.
With any serotonergic drugs, there is the additional risk of serotonin syndrome or serotonin toxicity where serotonin excess in the body leads to the sympathetic consequences such as hypertension, tachycardia, diaphoresis, and agitation. Fentanyl, another serotonergic drug, should also be considered carefully when used with patients with methamphetamine SUD. Benzodiazepines as well as serotonin antagonists can be considered in the case that a patient presents with serotonin toxicity 4.
Lastly, patients may be prescribed methamphetamine in low doses for certain conditions. Care providers have been directed to continue medications perioperatively, as there has been little to no evidence to indicate a danger to a patient using methamphetamines as prescribed 1,4.
References
1. Beaulieu, P. Anesthetic implications of recreational drug use. Can J Anesth/J Can Anesth 64, 1236–1264 (2017). https://doi.org/10.1007/s12630-017-0975-0
2. Cruickshank, C.C. and Dyer, K.R. (2009), A review of the clinical pharmacology of methamphetamine. Addiction, 104: 1085-1099. https://doi.org/10.1111/j.1360-0443.2009.02564.x
3. Eilert, R.J., Kliewer, M.L. Methamphetamine-induced Rhabdomyolysis. Int Anesthesiol Clin. 2011;49:52–56. https://doi.org/10.1097/AIA.0b013e3181ffc0e5
4. Krogh, J., Lanzillota-Rangeley, J., Paratz, E., Reede, L., Stone, L., Szokol, J., . . . Kearney, J. (2021). Practice Considerations for the Anesthesia Professional for Methamphetamine Substance Use Disorder Patients. Newsletter: The Official Journal of Anesthesia Patient Safety Foundation, 36(2), 67-73. https://www.apsf.org/article/practice-considerations-for-the-anesthesia-professional-for-methamphetamine-substance-use-disorder-patients/.
5. Moran, S., Isa, J., Steinemann, S. Perioperative Management in the Patient with Substance Abuse. Surgical Clinics of North America. Volume 95, Issue 2,2015, 417-428. https://doi.org/10.1016/j.suc.2014.11.001.