Amfetamine Abuse and Intoxication

Synonyms for amfetamines - speed, sulphate, whizz, billy, dexys, base
Synonyms for methamfetamine - meth, ice, crystal, crank, glass, tina, yaba

• Amfetamines are a widely abused class of drugs.
• They were used legally between the 1930s and 60s, with mainstream prescribing for multiple medical uses but rarely now (limited indications: ADHD, narcolepsy, exceptionally for depression; no longer used for weight loss).
• They are relatively easily manufactured in numerous illegal laboratories and are readily available on the streets, varying considerably in purity and potency.
• Khat is the only known organically derived amfetamine (leaves of Qat tree of East Africa and Arabian Peninsula).
• They have central and peripheral sympathomimetic action and are powerful and addictive stimulants.
• Amfetamines may be snorted, smoked, injected or ingested, and even small doses may exert a profound effect. Depending on the method of administration the user may experience an intense "rush" or a prolonged "high". Both effects are thought to be due to the release of high levels of dopamine into the pleasure-regulating areas of the brain. Chronic users develop a tolerance and dose levels may escalate. This appears to be particularly true of methamfetamine.
• Overdose in occasional and chronic abusers is common.

Methamfetamine and related compounds are among the most commonly used illegal drugs with an estimated 35 million users worldwide.
In the UK, the 2002-3 British Crime Survey reported a 1.6% prevalence of amfetamine use in adults aged 16-59 over the previous year¹. They are Class B drugs with possession risking up to 5 years' imprisonment and a fine.
In America, methamfetamine use spread from Hawaii and California during the 1990s and now has epidemic proportions, particularly in rural and semirural areas with devastating medical and social complications².

The effects of amfetamine abuse can be divided into immediate, long term and withdrawal effects.

Immediate effects

• "Rush" or "High".
• Rapid and/or irregular heartbeat.
• Increase in blood pressure.
• Increase in body temperature.
• Increase in respiratory rate.
• Increased wakefulness, agitation.
• Convulsions.
• Tremor.
• Nausea and vomiting, dry mouth, diarrhoea.
• Damage to nerve endings in dopamine containing areas of the brain, even after a single dose.
• Anorexia.

Long term effects:

• Addiction.
• Violent behaviour.
• Anxiety.
• Confusion.
• Visual ,sensory and auditory hallucinations.
• Mood disturbance.
• Weight loss.
• Repetitive motor activity .
• Formication (sensory hallucination of insects crawling on/under skin leading to obsessive scratching) and ulceration.

Withdrawal effects ⁴

Methamfetamine withdrawal severity declines from an initial peak within 24 hours of last use to near control levels by the end of the first week. This acute phase of withdrawal is characterised by:

• Increased eating.
• Fatigue and increased sleeping.
• Depression.
• Anxiety and craving-related symptoms.

• Abuse of other stimulants such as cocaine.
• Hyperthyroidism.
• Psychotic illness eg schizophrenia, mania.
• Alcohol withdrawal.

Consider the use of other substances - urine tox screen may be helpful. Amfetamines are detectable in urine for about 48 hours after use.
Other investigations depend on symptomatology and extent of toxicity/overdose - for example, electrolytes, renal and liver function, creatinine kinase, ECG, CXR, neurological imaging.

There is no specific treatment available for amfetamine overdose or intoxication, and both immediate and long term management is symptomatic and supportive.

Immediate management

Any of the following may be of use in the immediate management of amfetamine toxicity depending on the severity of the presenting condition:

• Observation in a safe quiet environment.
• Benzodiazepines (although beware development of co-dependency on these for 'come-down').
• Anticonvulsants.
• Ice baths to reduce temperature.

Long term management

Addicts and perhaps their families will require long term support, and several specialist agencies exist that are able to provide assistance (see web links below). The first port of call is the local Drug Treatment Centre for any addict who has asked for help, or is prepared to receive help. Harm reduction and general medical services are important and specific treatment strategies may include:

• Cognitive therapy.
• Antidepressant drugs (note, very limited evidence of benefit of tricyclics or SSRIs⁵).
• Neuroleptic drugs.
• Replacement therapy (similar to the use of methadone with opiate dependency) has been tried (reducing doses of dexamfetamine sulphate, a longer acting amfetamine to substitute for street drug use) but this is not standard and largely research based⁶.

• Stroke (due to hypertensive crisis or vasospasm).
• Myocardial infarction.
• Pulmonary oedema.
• "Meth mouth" - severe dental caries due to decreased saliva flow (xerostomia)⁷.
• Trauma due to intoxication.
• Life-threatening burns from fires and explosions associated with volatile substances used in production of methamfetamine⁸.
• Lead and other chemical poisoning - from exposure to chemicals used in production of drugs.
• Increased risk of HIV and other STDs - increased high risk sexual behaviour^{9 10}.
• Complications of IV use (cellulitis, phlebitis, vasculitis, bacterial endocarditis, infections spread by equipment sharing)
• Neglect and abuse of dependent children.
• Use in pregnancy associated with high risk of premature delivery and low birth weight¹¹.
• Drug-induced psychosis.
• Cognitive impairment with long-term use.

Largely outside clinical sphere - importance of education and law enforcement.