Amfetamine (Amphetamine) Abuse and Intoxication

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

There is a specific article on Crystal Methamfetamine Drug Abuse.

Amfetamines are the second most widely abused class of drugs internationally, with approximately 35 million users worldwide.¹ They have central and peripheral sympathomimetic action and are powerful and addictive stimulants.
They are relatively easily manufactured in numerous illegal laboratories and are readily available on the streets, varying considerably in purity and potency.

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.

They were used legally between the 1930s and 60s, with mainstream prescribing for multiple medical uses but rarely now. Current limited indications include:

• ADHD
• Narcolepsy
• Exceptionally for depression

They should no longer be used for weight loss.

There is some evidence of the abuse of Ritalin (prescribed for ADHD) both for recreational purposes, appetite suppression and by students to increase their ability to study and concentrate.^2,3
N.B. Khat is the only known organically derived amfetamine and is extracted from the leaves of the Qat tree found in East Africa and the Arabian Peninsula.

• 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 year.⁴ 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 complications.⁵

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
• 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 effects⁷

Amfetamine 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 e.g. schizophrenia, mania
• Alcohol withdrawal

• Consider the use of other substances - a toxicology 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, creatine kinase (to exclude rhabdomyolysis which may complicate overdose), 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.

Withdrawal is common amongst regular amfetamine users (reported prevalence of 87%) with intense and prolonged cravings being dominant symptoms. There is very little evidence regarding the appropriate management, whether psychological or biological.⁹ Reboxetine has been used to treat withdrawal but there is no trial evidence to support this approach.¹⁰

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 user 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 and behavioural therapies¹¹
• Antidepressant drugs (note, very limited evidence of benefit of tricyclics or SSRIs)¹²
• Neuroleptic drugs
• Replacement therapy with dexamfetamine sulphate, a longer acting amfetamine, to substitute for street drug use (largely research-based and not standard treatment)¹³

• Stroke (due to hypertensive crisis or vasospasm)¹⁵
• Myocardial infarction¹⁶
• Pulmonary oedema
• "Meth mouth" (severe dental caries due to decreased saliva flow or xerostomia)¹⁷
• Trauma due to intoxication
• Life-threatening burns from fires and explosions associated with methamfetamine production¹⁸
• Lead and other chemical poisoning from exposure to chemicals used in drug production
• Increased risk of HIV and other STDs due to increased high risk sexual behaviour^19,20
• Complications of IV use (e.g. 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 weight^21,22
• Drug-induced psychosis
• Anxiety, depression and increased risk of suicide
• Cognitive impairment with long-term use

An Australian study showed that amfetamine use by 17 years old was associated with increased risk of a range of other substance abuse, worse psychological morbidity and social problems in early adulthood. Some of this could be accounted for by their even earlier onset cannabis use.²³

This is largely outside the clinical sphere with education and law enforcement leading in efforts to control abuse.
Internet trade poses particular issues. However, it should be remembered that historically there has been a link between overprescription of amfetamines and their misuse so that a culture of rational prescribing should be developed for their legitimate use.¹ Where prescribed and used in a domestic or educational setting, provision should be made to ensure these drugs are not diverted for illicit use.