Synonyms: street names include 'meth', 'crystal meth', 'ice', 'glass', 'Tina', 'Christine', 'crank', 'tik', 'yaba' and 'crazy medicine'

Methamfetamine (METH) is an amfetamine-type stimulant. Within the central nervous system (CNS), it blocks presynaptic catecholamine reuptake, causing hyperstimulation at the post-synapse. See more general separate article Amfetamine Abuse and Intoxication.

It is most commonly smoked in its crystal form ('ice') in a pipe or in aluminium foil, heated by a flame below, but can also be snorted, injected, swallowed in pill form ('yaba') or inserted rectally. Smoking the drug increases its bioavailability compared with an oral formulation, and decreases plasma half-life. Mean plasma half-life after smoking is about 11 hours. Smoking approaches the bioavailability of injecting.¹ Its effects are compared to those of crack cocaine (euphoria, heightened arousal and increased energy) but longer-lasting due to the longer half-life. It is also highly addictive.

It can be made easily in clandestine home laboratories and is often adulterated with the chemicals used in its synthesis.

Over the 1990s, there was an epidemic of METH use in some parts of America. Whilst amfetamine and ecstasy have been widely used across the UK and Europe, crystal methamfetamine use has been, and remains to date, uncommon although rates may be increasing. It has been reclassified as a Class A drug so as better to control emergent problems associated with its use.

Epidemiology

In the USA, rates of methamfetamine use grew steadily over the 1990s, but are thought to have stabilised, with 2.8% of 18-26 year-olds reporting use in the last year. Its popularity spread from Hawaii and California and use is now highest in western and north central states, presenting significant medical and social problems in rural as well as urban populations.² METH abuse has spread throughout the world - with high rates in countries such as Thailand, South Africa, Australia, Pacific island states and Mexico.

In the UK, epidemiological data have tended to look at amfetamine and methamfetamine use together. However, for the first time the 2008/2009 British Crime Survey asked individuals specifically about methamfetamine use. 0.9% adults aged 16-59 years reported ever using, and 0.1% reported use in the previous month.³

Presentation^1,2,4

Abusers typically self-administer the drug in 'runs' of several days, with intervening periods of abstinence.⁵ Whilst on a 'run', an individual may stay awake continuously for up to 10 days with little food or drink. Prolonged sleep and mild dysphoria occur as the drug wears off.
Immediate subjective effects include:

• Euphoria.
• Increased alertness.
• Increased energy.
• Increased libido and enhanced sexual pleasure.
• Decreased inhibition.
• Decreased appetite.
• Decreased need for sleep.

Peripheral actions arise due to the indirect sympathomimetic effects of the drug:

• Tachycardia.
• Hypertension.
• Palpitations.
• Tachypnoea.
• Sweating and hyperthermia.
• Dry mouth.
• Decreased gastrointestinal (GI) motility.
• Dilated pupils.
• Tremor.

Central actions may account for some of the other typical behaviours and movement disorders seen such as:

• Jaw clenching.
• Repetitive jerking and choreoathetoid movements.
• Compulsion with repetitive tasks ('punding').
• Formication (sensation of flesh crawling with bugs with associated compulsive picking and infected sores).

Repetitive movements, hyperactivity, and difficulty focusing thought are sometimes referred to as 'tweaking'.⁴

• A violent mechanism of injury.
• Gun and stab wounds.
• Attempted suicide.
• Domestic violence.
• Death from injuries.

Aside from the risks associated with the use of METH, there are hazards associated with the production of METH and toxic waste exposure. Those indirectly involved (neighbours, family members, children and emergency personnel) as well as users and producers may present with:

• Serious burns due to explosions (METH labs explode due to volatile substances used in production).⁸
• Symptoms of environmental exposure (e.g. headache, nausea, dizziness, dyspnoea and eye irritation).
• Heavy metal poisoning.

Differential diagnosis

The differential is wide and includes:

• Hypertensive crisis.
• Hyperthyroidism.
• Toxicity from other stimulant/sympathomimetic/hallucinogen.
• Schizophrenia.

Be aware that many patients will not only have used METH - polydrug use (including alcohol) is the norm, so consider whether there is a mixed picture.

Investigations

• Diagnostic testing:
  • Urine - METH is detectable for 48 hours after use.
  • Hair analysis.
  • Meconium testing - the most accurate method in neonates.
• Other laboratory tests should be directed towards symptoms:
  • Blood tests - FBC, U&Es, creatine kinase (CK), cardiac enzymes.
  • ECG.
  • CXR - where there are pulmonary symptoms.
  • CT scan - where there is altered mental status.
• Sexual health promotion - offer sexually transmitted disease (STD) and pregnancy testing.

Management

Acute intoxication⁴

• Consider staff safety - patients may be highly agitated and unpredictable. Call for security/police back-up where necessary. Sedation with neuroleptics, e.g. haloperidol, may be required.
• Management is largely supportive.
• Activated charcoal is only helpful where there has been oral ingestion.
• Benzodiazepines are indicated for seizures.
• Cooling measures may be necessary where there is hyperthermia.
• Treatment of hypertension may require intravenous betablockers.
• The use of olanzapine and risperidone to treat amfetamine-related psychosis is also under investigation.
• Before discharge, consider additional needs and referrals. For example, drug and alcohol team, psychiatry, social services (consider child protection issues) and genitourinary medicine (GUM) clinic.

Withdrawal²

• Symptoms include:
  • Depression
  • Anxiety
  • Irritability
  • Problems with concentrating
  • Psychomotor slowing
  • Increased appetite
  • Paranoia
• Withdrawal from stimulants is considered less dangerous than from alcohol, opioids or sedatives, but seizures are possible.
• Compared with cocaine withdrawal, METH withdrawal is considered to produce more severe and prolonged depression so careful monitoring for suicidal ideation is important.

Treatment of abuse and dependence

• There is no effective treatment currently. Research into pharmacological treatment for METH dependence is ongoing - candidate drugs have included bupropion, mirtazapine, baclofen, and topiramate.⁹ However, medication is considered primarily an adjunct to the use of psychosocial interventions.
• Outpatient behavioural therapies are the standard treatment currently in the USA. The use of cognitive behavioural therapy and contingency management have been borrowed from the treatment of cocaine addiction and applied to methamfetamine and have been shown to be effective in reducing use in the short-term, although longevity has yet to be proven.¹⁰ Contingency management gives rewards to patients who provide drug-free urine specimens.¹¹
• Support groups and 12-step treatment programmes may also offer benefit.¹²

Complications

For METH users

The morbidity associated with METH use is considerable:

• Myocardial infarction, dissecting aortic aneurysm, cardiomyopathy.¹³
• Hypertensive crises and stroke.
• Rhabdomyolysis and renal failure.
• 'Crystal cock' (erectile dysfunction).
• GI ulcers and ischaemic colitis.
• Pulmonary hypertension.¹⁴
• Skin abscesses and lesions.
• Premature ageing.
• Cognitive impairment - confusion, memory loss, motor slowing and learning impairment.¹⁵
• 'Meth mouth' (dental decay).^16,17
• Psychiatric disorders:
  • Anxiety
  • Depression
  • Psychosis
  • Suicidal ideation and behaviour
• Malnutrition and weight loss.
• Dependence and withdrawal-related symptoms.
• Trauma-related injuries.

In pregnancy

• Placental insufficiency and abruption.
• Intrauterine growth restriction.¹⁸
• Prematurity.
• Cleft palate defects.
• Cardiac anomalies.
• Miscarriage and stillbirth.

For children of METH users

• Neonatal withdrawal (usually milder than with opiate withdrawal - abnormal sleep, poor feeding, decreased movement and arousal, increased stress response).¹⁹
• Long-term effects of intrauterine exposure are unclear - possible developmental delay.
• Neglect and abuse.
• Inadvertent poisoning and trauma.

Public health issues

• Environmental health risk from illicit laboratories and illegal toxic waste.
• Increased rate of STD transmission, in particular HIV.²⁰
• Increased levels of crime and violence.

Prognosis

METH use is associated with rapid dependence and sharp physical decline, often accompanied by criminality. Cases of acute uncomplicated toxicity treated rapidly and appropriately have a good prognosis,⁴ but outcome associated with chronic use is much less positive. Relapse rates following treatment for dependence are high (one study suggesting 36% under 6 months and a further 15% between 7-19 months).²¹ Anecdotal evidence in areas with high METH use suggests significant drug-related death rates, either direct (related to toxicity) or more often indirect (e.g. road traffic accidents, homicide, suicide).

Prevention

Efforts in North America have centred around education (including high-profile, 'shock' advertisements), targeted interventions to those considered high-risk (e.g. pregnant women users) and law enforcement strategies such as limiting the availability of precursor substances - for example, pseudoephedrine (found in cold remedies and decongestants). This has limited success at the expense of limiting access to the public to effective medicines.²²

Document references

1. Schifano F, Corkery JM, Cuffolo G; Smokable ("ice", "crystal meth") and non smokable amphetamine-type stimulants: clinical pharmacological and epidemiological issues, with special reference to the UK. Ann Ist Super Sanita. 2007;43(1):110-5. [abstract]
2. Winslow BT, Voorhees KI, Pehl KA; Methamphetamine abuse. Am Fam Physician. 2007 Oct 15;76(8):1169-74. [abstract]
3. Drug Misuse Declared: Findings from the 2008/09 British Crime Survey, England and Wales, Home Office, July 2009
4. Derlet R; Toxicity, Methamphetamine, eMedicine, Dec 2009
5. Haile CN, Kosten TR, Kosten TA; Pharmacogenetic treatments for drug addiction: cocaine, amphetamine and Am J Drug Alcohol Abuse. 2009;35(3):161-77. [abstract]
6. Wako E, LeDoux D, Mitsumori L, et al; The emerging epidemic of methamphetamine-induced aortic dissections. J Card Surg. 2007 Sep-Oct;22(5):390-3. [abstract]
7. Swanson SM, Sise CB, Sise MJ, et al; The scourge of methamphetamine: impact on a level I trauma center. J Trauma. 2007 Sep;63(3):531-7. [abstract]
8. Spann MD, McGwin G Jr, Kerby JD, et al; Characteristics of Burn Patients Injured in Methamphetamine Laboratory Explosions. J Burn Care Res. 2006 July/August;27(4):496-501. [abstract]
9. Rose ME, Grant JE; Pharmacotherapy for methamphetamine dependence: a review of the pathophysiology Ann Clin Psychiatry. 2008 Jul-Sep;20(3):145-55. [abstract]
10. Lee NK, Rawson RA; A systematic review of cognitive and behavioural therapies for methamphetamine dependence. Drug Alcohol Rev. 2008 May;27(3):309-17. [abstract]
11. Roll JM, Petry NM, Stitzer ML, et al; Contingency management for the treatment of methamphetamine use disorders. Am J Psychiatry. 2006 Nov;163(11):1993-9. [abstract]
12. Donovan DM, Wells EA; 'Tweaking 12-Step': the potential role of 12-Step self-help group involvement in methamphetamine recovery. Addiction. 2007 Apr;102 Suppl 1:121-9. [abstract]
13. Yeo KK, Wijetunga M, Ito H, et al; The association of methamphetamine use and cardiomyopathy in young patients. Am J Med. 2007 Feb;120(2):165-71. [abstract]
14. Chin KM, Channick RN, Rubin LJ; Is methamphetamine use associated with idiopathic pulmonary arterial hypertension? Chest. 2006 Dec;130(6):1657-63. [abstract]
15. Scott JC, Woods SP, Matt GE, et al; Neurocognitive effects of methamphetamine: a critical review and meta-analysis. Neuropsychol Rev. 2007 Sep;17(3):275-97. [abstract]
16. Shetty K, "Meth Mouth" eMJA 2006; 185 (5): 292; Includes illustrative photo
17. Saini T, Edwards PC, Kimmes NS, et al; Etiology of xerostomia and dental caries among methamphetamine abusers. Oral Health Prev Dent. 2005;3(3):189-95. [abstract]
18. Smith LM, Lagasse LL, Derauf C, et al; Prenatal methamphetamine use and neonatal neurobehavioral outcome. Neurotoxicol Teratol. 2008 Jan-Feb;30(1):20-8. Epub 2007 Oct 3. [abstract]
19. Smith LM, LaGasse LL, Derauf C, et al; The infant development, environment, and lifestyle study: effects of prenatal methamphetamine exposure, polydrug exposure, and poverty on intrauterine growth. Pediatrics. 2006 Sep;118(3):1149-56. [abstract]
20. Garofalo R, Mustanski BS, McKirnan DJ, et al; Methamphetamine and young men who have sex with men: understanding patterns and correlates of use and the association with HIV-related sexual risk. Arch Pediatr Adolesc Med. 2007 Jun;161(6):591-6. [abstract]
21. Hillhouse MP, Marinelli-Casey P, Gonzales R, et al; Predicting in-treatment performance and post-treatment outcomes in methamphetamine users. Addiction. 2007 Apr;102 Suppl 1:84-95. [abstract]
22. Eccles R; Substitution of phenylephrine for pseudoephedrine as a nasal decongeststant. An illogical way to control methamphetamine abuse. Br J Clin Pharmacol. 2007 Jan;63(1):10-4. Epub 2006 Nov 20. [abstract]

Internet and further reading

• The Meth Project; US prevention programme
• Partnership for a drug free America, Faces of Meth; Alarming pictures showing effect of Meth abuse on appearance
• Terence Higgins Trust Drugfucked; Site for gay men providing information about the use of street drugs including METH and GHB

Acknowledgements