Crystal Methamfetamine Drug Abuse

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

Methamfetamine (METH) is an amfetamine-type stimulant (others include amfetamine and MDMA/ecstasy). Within the CNS, it blocks presynaptic catecholamine reuptake, causing hyperstimulation at the post-synapse. See more general article on amfetamine drug abuse.

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 to an oral formulation, and decreases plasma half-life. Smoking approaches the bioavailability of injecting.¹ Its effects are compared to those of crack cocaine (euphoria, heightened arousal and increased energy) and it is also highly addictive.

It can be easily made in clandestine home laboratories and, in its street form, it 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 appear to be increasing. It was recently reclassified to a Class A drug within the UK, so as to better control the emergent problems associated with its use.

In the US, 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 tends to look at amfetamine and methamfetamine use together. In the 2003-4 British Crime Survey a 4% prevalence of use in adults aged 16-24 years over the previous year was reported.³ A recent study, looking at the rates of enquiries to a London poisons' centre and emergency department attendance, argue that crystal methamfetamine use whilst growing, remains a relatively rare problem.⁴ They compared the rates of calls to the poisons' centre about recreational drug side-effects/overdose: in 2000 only 0.1% calls were regarding crystal meth, this had risen to 1.23% in 2006 compared to 42.7% regarding MDMA. Similarly, in 15 month period, 5 methamfetamine cases presented to the emergency department of a large London teaching hospital compared to 171 MDMA cases. They argue for perspective and rational allocation of resources, rather than scare-mongering.

Certain groups are associated with its use in the UK, in particular, gay men. One study suggested that 10% London's gay men had used it in the last year, most infrequently. This rose to 19.5% of gay men attending gyms, thought to correlate with those involved in the club scene.⁵ METH's association with increased sexual desire and unsafe sex practices has caused concern in this context.

Immediate subjective effects include:

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

Prolonged sleep and mild dysphoria occur as the drug wears off. Mean plasma half-life after smoking is about 11 hours.

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

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

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

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

Within healthcare, individuals using methamfetamine usually come to attention due to adverse events/side-effects related to their drug use.

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

Asides 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 volatile substances used in production)⁹
• Symptoms of environmental exposure (e.g. headache, nausea, dizziness, dyspnoea and eye irritation)
• Heavy metal poisoning

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.

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

Acute intoxication⁶

• Consider staff safety - patients may be highly agitated and unpredictable. Call for security/police back-up where necessary. Sedation 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 beta-blockers.
• Before discharge, consider additional needs and referrals. For example, drug and alcohol team, psychiatry, social services (consider child protection issues) and GUM.

Withdrawal²

• Symptoms include:
  • Depression
  • Anxiety
  • Irritability
  • Problems concentrating
  • Psychomotor slowing
  • Increased appetite
  • Paranoia
• Withdrawal from stimulants is considered less dangerous than from alcohol, opioids or sedatives, but seizures are possible.
• Compared to 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 on-going - candidate drugs have included bupropion and risperidone.
• 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. Contingency management gives rewards to patients who provide drug-free urine specimens.¹⁰ Behavioural approaches have been shown to reduce sexual risk taking and METH use for up to a year in one study.¹¹
• Support groups and 12-step treatment programmes may also offer benefit.¹²

For METH users

The morbidity associated with METH use is considerable:

• Myocardial infarction, dissecting aortic aneurysm, cardiomyopathy¹³
• Hypertensive crises and stroke
• Rhabdomyolysis and renal failure
• 'Crystal cock' (erectile dysfunction)
• GI ulcers and ischaemic colitis
• Pulmonary hypertension¹⁴
• Skin abscesses and lesions
• Premature aging
• Cognitive impairment - confusion, memory loss, motor slowing and learning impairment¹⁵
• '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 retardation¹⁸
• 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 HIV²⁰
• Increased levels of crime and violence

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,⁶ 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 suggest significant drug-related death rates, either direct (related to toxicity) or more often indirect (e.g. RTAs, homicide, suicide).

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 such as pseudoephedrine (found in cold remedies and decongestants). This has limited success at the expense of limiting access to the public to effective medicines.²²