Professional Reference articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.
Synonyms: street names for amfetamines include 'speed', 'sulphate', 'whizz', 'billy', 'dexys', 'base'. Street names for methamfetamine include 'meth', 'ice', 'crystal', 'crank', 'glass', 'tina', 'yaba'
See related separate article Crystal Methamfetamine Drug Abuse.
Amfetamines are the second most widely abused class of drugs internationally, with approximately 35 million users worldwide. 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. 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.
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 1960s, with mainstream prescribing for multiple medical uses but rarely now. Current limited indications include:
They should no longer be used for weight loss. There is some evidence of the abuse of methylphenidate (prescribed for ADHD) - for recreational purposes, appetite suppression and cognitive 'enhancement', increasing students' ability to study and concentrate.[2, 3]
Amfetamines are Class B drugs with possession risking up to 5 years' imprisonment and a fine, unless prepared for injection when they are Class A drugs with higher penalties.
In England and Wales, the 2008-2009 British Crime Survey found a self-reported 1.2% prevalence of amfetamine use in adults aged 16-59 over the previous year and 2.6% prevalence in 16-24 year-olds. A downward trend in use has been observed since 1996 when 3.2% of 16-59 year olds reported use in the previous year.
The effects of amfetamine abuse can be divided into immediate, long-term and withdrawal effects.
- 'Rush' or 'high'.
- Rapid and/or irregular heartbeat.
- Increase in blood pressure.
- Increase in body temperature.
- Increase in respiratory rate.
- Increased wakefulness.
- Nausea and vomiting, dry mouth, diarrhoea.
- Damage to nerve endings in dopamine-containing areas of the brain.
- Violent behaviour.
- 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.
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.
- Anxiety and craving-related symptoms.
- Abuse of other stimulants such as cocaine.
- Psychotic illness, eg 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, and neurological imaging.
There is no specific treatment available for amfetamine overdose or intoxication, and both immediate and long-term management is symptomatic and supportive.
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').
- 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. A recent Cochrane review concluded that no medication is effective for treatment of amfetamine withdrawal. Amineptine improved discontinuation rates but had no effect on reducing withdrawal symptoms or craving. It is not used in clinical practice due to concerns regarding the potential for abuse of the drug. Mirtazapine showed benefits in withdrawal symptoms over placebo in one randomised controlled trial, but no benefit in another.
There is a very limited evidence base for the treatment of amfetamine psychosis but antipsychotic medication is thought to be effective in reducing symptoms.
Addicts and perhaps their families will require long-term support, and several specialist agencies exist which 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 therapies.
- Antidepressant drugs (Note: very limited evidence of benefit of tricyclics or selective serotonin reuptake inhibitors (SSRIs).
- Neuroleptic drugs.
- Stroke (due to hypertensive crisis or vasospasm).
- Myocardial infarction.
- Pulmonary oedema.
- Trauma due to intoxication.
- Lead and other chemical poisoning from exposure to chemicals used in drug production.
- Complications of intravenous (IV) use (eg 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 birthweight.
- Drug-induced psychosis.
- Anxiety, depression and increased risk of suicide.
- Cognitive impairment with long-term use.
An Australian study showed that amfetamine use before the age of 17 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.
This is largely outside the clinical sphere with education and law enforcement leading in efforts to control abuse. 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. Where prescribed and used in a domestic or educational setting, provision should be made to ensure these drugs are not diverted for illicit use.
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Further reading & references
- Attention deficit hyperactivity disorder: diagnosis and management; NICE Clinical Guideline (September 2008)
- Ghodse H; 'Uppers' keep going up. Br J Psychiatry. 2007 Oct 191:279-81.
- InfoFacts: Stimulant ADHD Medications - Methylphenidate and Amphetamines (Last revised 6/09), National Institute on Drug Abuse; Drug information provided by the American National Institute of Health (NIH)
- Arria AM, Caldeira KM, O'Grady KE, et al; Nonmedical use of prescription stimulants among college students: associations with attention-deficit-hyperactivity disorder and polydrug use. Pharmacotherapy. 2008 Feb 28(2):156-69.
- Drug Misuse Declared: Findings from the 2008/09 British Crime Survey, England and Wales; Home Office, July 2009 (archived content)
- Oxford Textbook of Psychiatry. Gelder M et al (ed) 2000. OUP. ISBN 01985 28108
- McGregor C, Srisurapanont M, Jittiwutikarn J, et al; The nature, time course and severity of methamphetamine withdrawal. Addiction. 2005 Sep
- Handly N; Amfetamine toxicity, eMedicine, Oct 2009
- Shoptaw SJ, Kao U, Heinzerling K, et al; Treatment for amphetamine withdrawal. Cochrane Database Syst Rev. 2009 Apr 15 (2):CD003021.
- Shoptaw SJ, Kao U, Ling W; Treatment for amphetamine psychosis. Cochrane Database Syst Rev. 2009 Jan 21 (1):CD003026.
- Lee NK, Rawson RA; A systematic review of cognitive and behavioural therapies for methamphetamine dependence. Drug Alcohol Rev. 2008 May 27(3):309-17.
- Srisurapanont M, Jarusuraisin N, Kittirattanapaiboon P; Treatment for amphetamine dependence and abuse. Cochrane Database Syst Rev. 2001
- Darke S, Kaye S, McKetin R, et al; Major physical and psychological harms of methamphetamine use. Drug Alcohol Rev. 2008 May 27(3):253-62.
- Westover AN, McBride S, Haley RW; Stroke in young adults who abuse amphetamines or cocaine: a population-based study of hospitalized patients. Arch Gen Psychiatry. 2007 Apr 64(4):495-502.
- Westover AN, Nakonezny PA, Haley RW; Acute myocardial infarction in young adults who abuse amphetamines. Drug Alcohol Depend. 2008 Jul 1 96(1-2):49-56. Epub 2008 Mar 19.
- Furara SA, Carrick P, Armstrong D, et al; The outcome of pregnancy associated with amphetamine use. J Obstet Gynaecol. 1999 Jul
- Degenhardt L, Coffey C, Moran P, et al; The predictors and consequences of adolescent amphetamine use: findings from the Victoria Adolescent Health Cohort Study. Addiction. 2007 Jul 102(7):1076-84.
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