31st January 2024

Stimulants

Background

Stimulants are another substance classification commonly used recreationally. They include ecstasy (MDMA), amphetamines and cocaine. Some amphetamines, such as dexamphetamine, have been prescribed for Attention Deficit Hyperactivity Disorder (ADHD). They enhance the release of serotonin, dopamine and norepinephrine  (monoamine) neurotransmitters by blocking reuptake, resulting in increased levels within neural synapses. The excess release of these neurotransmitters causes the euphoria commonly experienced when they are ingested, increasing the risk of dependence. However, after prolonged use, levels of these neurotransmitters become depleted, causing long-term effects on cognition and mood.

MDMA reaches peak concentration in the blood approximately 2 hours post-ingestion and undergoes hepatic metabolism; however, it has an extensive half-life, which may account for the longevity of symptoms.

Amphetamines were first marketed as a treatment for nasal congestion; however, due to their high abuse potential, very few today remain medically licensed, e.g., for the treatment of narcolepsy or Parkinson’s disease. They can be injected, smoked or taken orally.

Cocaine is sourced from the coca plant and can be ingested orally, nasally or injected. The effects last up to one hour after consumption, and it has a short half-life. Topically, cocaine can have an anaesthetic effect as well as cause vasoconstriction, but if enough is absorbed systemically, alpha and beta adrenoreceptors may be stimulated, which causes tachycardia.

Presentation

Intoxication can cause insomnia, euphoria, agitation, headache, poor appetite, and mydriasis. Toxicity can result in seizures, psychosis, chest pain and strokes. Withdrawal can cause a ‘crash,’ lethargy and low mood.

Co-administration of amphetamines with other serotonergic drugs can cause serotonin syndrome and, if taken within 2 weeks of a MAOI, can cause a hypertensive crisis.

Diagnosis

Urine testing can detect traces of most stimulants for 2-3 days. Patients presenting with tachycardia will require an ECG to explore this, and any seizures or reduced consciousness will need to be managed and investigated, e.g., via CT head.

Differential diagnosis

The effects of stimulant use can mimic independent psychiatric disorders, such as anxiety, panic disorder, and the mania phase of bipolar disorder. Drug-induced psychosis can also occur.

Management 

Aside from the acute management required if a person presents severely unwell after stimulant use/withdrawal, psychosocial intervention and harm reduction are the key components of management for stimulant misuse. Any side effects from stimulant misuse and/or withdrawal, including acute co-presenting or coexisting psychiatric disorders, should be managed symptomatically as indicated, with reassurance and support offered. Specific targeted pharmacological therapies have been explored in relation to management of stimulant misuse; however, to date, there is little evidence that these have been effective in supporting and maintaining sobriety, hence the current recommendation for psychosocial interventions to remain the mainstay of treatment. Safety advice should also be given, e.g., in relation to injection safety if the substances are being taken intravenously.

References

• Clinical Guidelines on Drug Misuse and Dependence Update 2017 Independent Expert Working Group. Drug misuse and dependence: UK guidelines on clinical management. UK: Department of Health; 2017.
• Vasan S, Olango GJ. Amphetamine Toxicity. StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK470276/
• NIDA. “What are MDMA’s effects on the brain?.” National Institute on Drug Abuse, 13 Apr. 2021, https://nida.nih.gov/publications/research-reports/mdma-ecstasy-abuse/what-are-mdmas-effects-on-brain Accessed 3 Dec. 2022.
• CAMH. Amphetamines [Internet]. Centre for Addiction and Mental Health. 2012 [cited 2022Dec3]. Available from: https://www.camh.ca/en/health-info/mental-illness-and-addiction-index/amphetamines
• Kalant H. The pharmacology and toxicology of “ecstasy” (MDMA) and related drugs. CMAJ. 2001;165(7):917-928.
• Martin D, Le JK. Amphetamine.StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK556103/
• Richards JR, Laurin EG. Cocaine. StatPearls. 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK430769/