This item is 5 years and 6 months old; some content may no longer be current.

Addressing methamphetamine use in primary care

Methamphetamine, commonly referred to in New Zealand as “meth” or “P”, is associated with high rates of personal and community harms. People who use methamphetamine have an increased risk of death due to overdose, suicide or cardiovascular causes. Any health interaction is an opportunity to discuss methamphetamine use if suspected and offer support to stop.

Log in

Key practice points:

  • Health professionals need to be proactive when the opportunity arises in identifying people who have problems with methamphetamine use, as they may have little contact with health services and are unlikely to reveal their drug use without being asked
  • Methamphetamine use is most prevalent among people aged in their 30s and under, and is more common in males compared with females and in Māori compared to people of other ethnicities
  • People who use methamphetamine are at risk of dependency, psychosis and other mental and physical health complications, as well as financial, family, relationship and legal problems
  • Counselling and support from a health professional, friends and family is currently the best approach for helping people to stop using methamphetamine
  • Evidence does not support the use of any currently available pharmacological treatments to help patients quit or prevent relapses
  • There are a variety of self-help resources and support programmes available that patients can be directed to

Methamphetamine, also known as meth or “P”, is a central nervous system stimulant that causes the release of dopamine, noradrenaline and serotonin.1 It is the most potent form of amphetamine-type drug, and is ranked as the most harmful drug in New Zealand for dependent users.2 The acute effects of ingestion, which resemble the “flight or fight” response, typically last four to eight hours and are similar to other psychostimulants, such as cocaine.1 It can be produced in powder, pill or crystal formulations, the latter also referred to as “ice”.

It produces a short-term high, followed by a crash

In survey data from Australia, the most common reasons people reported for taking methamphetamine were for the euphoric effect, to party or socialise, feel more confident or think more clearly.3 One in ten people reported taking it to focus better at work.3 Some people experience an increased libido with methamphetamine use, causing them to engage in risky or prolonged sexual activities, and increasing their risk of sexually transmitted or blood-borne infections.4

Following an initial high, people who use methamphetamine experience a crash or “come down” in the following days, which can include exhaustion, prolonged sleep, depression and anxiety. Over the next weeks, users may experience difficulty sleeping or concentrating, headaches, muscle pain, mood swings, depression, anxiety and agitation, which can result in taking another dose to relieve symptoms of withdrawal.1 Surveys have found that 20–30% of people using methamphetamine report being dependent, placing them at risk of long-term health consequences from chronic use.5, 6

People use it in a variety of ways, often alongside other substances

Methamphetamine is typically smoked in a glass pipe but can be swallowed, snorted or injected.4 Patterns of use vary, but people who frequently use methamphetamine often take it in a binge of multiple doses a day, for up to four days in a row, sleeping very little during that time.7 Methamphetamine is commonly used in combination with multiple substances, including cannabis, synthetic cannabinoids, GHB*, ecstasy, alcohol, methylphenidate, benzodiazepines and opioids such as tramadol.8

* Gamma-hydroxybutyric acid (GHB), also known by various other names such as “fantasy”, “waz” or “mils”, is a GABA B receptor agonist; it is sometimes used with methamphetamine and is associated with particularly severe withdrawal symptoms and overdose.

In surveys conducted in New Zealand over the last decade, 1–2% of people have reported using an amphetamine, of which methamphetamine is one of the most common types. It is either imported illegally or manufactured from precursors.9 Despite efforts to curb production and importation, usage rates are not going down, and methamphetamine is readily available; users in New Zealand report that they can get it within an hour.5, 9

In the most recent New Zealand Health Survey it was estimated that approximately 34,000 people aged 16–64 years had used an amphetamine in the past year (1.1% of the population).9 The highest rates of use were in males (1.7% vs. 0.6% in females), people aged from 25–34 years (2.4%) and people of Māori ethnicity; after adjusting for age and sex differences between populations, Māori were 3.4 times more likely to have used amphetamines in the past year than non-Māori.9 Analysis of drug metabolites in wastewater has found rates of methamphetamine use in Whangarei are two to four times higher than in Auckland or Christchurch, which is consistent with anecdotal reports of high rates of use in Northland.10, 11

Cardio- and cerebrovascular effects can occur during acute or chronic use, including hypertension, arrhythmias, myocardial infarction, stroke and heart failure.7, 12 In an Australian study of mortality related to methamphetamine use from 2009–2015, 22% of deaths were attributed to “natural disease” in conjunction with methamphetamine toxicity. The most frequent natural disease was a cardiac condition or stroke.13

Neurochemical and functional changes occur in the brain with chronic use, including cognitive impairment and an increased risk of Parkinson’s disease later in life.12, 14

Psychosis is estimated to affect three to four out of every ten people who chronically use methamphetamine.15 This may manifest as unusual thoughts or statements, delusions of persecution or grandiosity, auditory, visual or tactile hallucinations, such as feeling something crawling on or coming out of the skin.16 A small proportion of people can become aggressive or violent during an acute psychotic episode.1 The risk of psychosis is related to the formulation, dose, frequency and duration of use of methamphetamine, however, once a person has had a psychotic episode they are more likely to experience further episodes at lower doses, referred to as “kindling”.16 Psychosis typically resolves as the drug effect wanes, however, in approximately one-third of people, symptoms persist for several months, and some people are subsequently diagnosed with schizophrenia.16, 17

Anxiety and depression can result from methamphetamine use, particularly during the “come down” period. Surveys in New Zealand have found that approximately one-quarter of people who frequently use methamphetamine are also taking antidepressants.8 Suicidality is also more common among users of methamphetamine; 18% of methamphetamine-related deaths in Australia between 2009–2015 were suicide.13 The impulsivity, disinhibition and psychosis associated with methamphetamine use is likely to be a factor in this. Assessing patients presenting with symptoms of anxiety or depression for the possibility of drug use should be a routine aspect of practice.

Dental problems are common in people with chronic use. It is likely that this is caused by the adverse effects of methamphetamine such as dry mouth, teeth grinding and clenching, lack of attention to oral hygiene and acid erosion due to the substance itself. Accelerated or unusual dental problems affect approximately 40% of people who chronically use methamphetamine.18 This includes missing teeth, tooth erosion or extensive caries, lesions or abnormalities in the oral mucosa, problems with the temporomandibular joint, or the need for dentures at a young age.18

Many people who use methamphetamine want to use less and are open to help from a general practitioner. The Global Drug Survey, which is an international data collection on use of illegal drugs, found that people who used methamphetamine reported high rates of wanting to use less or seek help, second only to tobacco users.6 A survey in Australia of over 130 methamphetamine users reported that they would be most comfortable seeking help from friends or family members (38% of respondents), followed by health professionals such as a general practitioner or psychologist (29–31%).3

The crazed, violent image of a meth user is an extreme presentation

Methamphetamine users are often depicted in the media as violent or psychotic. However, while these instances can occur during acute intoxication, it does not reflect the typical circumstances of someone using methamphetamine.19, 20 People with mild to moderate problems with methamphetamine are more likely to be scared, anxious and on edge than violent, and can be treated in the community without health professionals or other support people being at risk of physical harm. In addition, the extreme image may cause some people to delay seeking help, as they believe their personal situation is not as bad as what they see in the media.19, 20

General practitioners already have the skills needed

Reasons why general practitioners should enquire about the use of methamphetamine in patients they see include:19,20

  • The best approach for helping patients to quit is counselling and psychological support, which general practitioners already use for helping patients with other problems such as addiction to smoking and alcohol
  • General practitioners are familiar with the life circumstances of regular patients, allowing them to offer independent advice which is personalised to the patient’s situation
  • There can be a large delay between when people start having problems from their drug use to when they seek help. As general practitioners may be one of the few health professionals people using methamphetamine interact with, they can help to close that gap by asking patients about their drug use.
  • Even if people are not ready to quit, general practitioners can help people to care for other aspects of their health and offer harm reduction advice (see: “Harm reduction for people who use methamphetamine”).

Be proactive in asking patients about methamphetamine use

Non-specific indicators which may suggest methamphetamine use include:1

  • Difficulty sleeping
  • Feeling on edge or agitated
  • Anxiety or depression
  • Worsening symptoms of psychosis
  • Aches or muscle pains
  • Lethargy and tiredness
  • Hypertension or chest pain
  • Unexplained weight loss
  • Lesions from excessive scratching due to itch or crawling sensations on the skin
  • Needle marks (if injecting methamphetamine)
  • Deteriorating dental health, e.g. missing teeth, tooth erosion or extensive caries
  • Unusual behaviours or statements about themselves or their environment

Methamphetamine use may be difficult for patients to disclose due to the stigma of being a drug user or fear of authorities finding out. Points to consider when asking patients about methamphetamine use include:19

  • Emphasise that the conversation is confidential and the only circumstances where a clinician would share the conversation with others is if the patient were a danger to themselves or others
  • Use open-ended questions. For example, after asking about smoking or alcohol use, ask “what about anything else?”, and repeat the question if necessary. People may disclose use of substances they feel are more acceptable first, e.g. admitting to cannabis use first and then methamphetamine use on further questioning.
  • For a patient who has symptoms or signs suggestive of use, statements such as: “A lot of people who use meth feel like this when they’re in withdrawal” or “I’ve treated patients who were coming off meth who tell me they felt like this”, may help them to feel that they are not alone in their situation

Counselling and support from a health professional, whānau/family and friends is the best approach to encourage withdrawal and abstinence from methamphetamine. As little as two sessions of counselling can help improve abstinence rates for people with methamphetamine dependency.20, 21 People must decide that they want to quit, and the role of the general practitioner is as a facilitator who helps them to come to that decision, then encourages perseverance once patients are attempting to quit (see: “Motivational interviewing can help people to reflect on their methamphetamine use”).

Addiction specialists advise intervening in the first consultation when methamphetamine use is disclosed.20 Clinicians may feel time-pressured to deal with the patient’s presenting issue first and discuss their methamphetamine use at another time. However, people who use methamphetamine may have little contact with health services and engaging with the patient can set the scene for later change and help them avoid future harm.

Points to consider in the initial appointment include:

  • Some people may disclose using methamphetamine, but have no intention of quitting – this can still be used as an opportunity to assess their health, e.g. investigations for blood-borne viruses for people who inject drugs or sexual health tests.20
  • Offer harm reduction advice to reduce the risks associated with ongoing methamphetamine use (see: “Harm reduction for people who use methamphetamine”)
  • Discuss with patients whether they would like to be referred to a specialist service or community help programme (see: “Patient information and further assistance”)
  • Before patients leave, ask them to commit to a follow-up appointment and make a booking for them before they go and set up a reminder
  • If appropriate, ask to include the patient’s whānau/family in treatment plans and consider their point of view and experience of the situation

Withdrawal symptoms can take weeks to months to resolve

A typical time course of withdrawal symptoms for someone chronically using methamphetamine is shown in Table 1. Symptoms of craving, depression and anxiety usually substantially improve over the first two weeks and return to normal levels for that person after approximately five weeks, although symptoms may be prolonged in some people.24

Reassure patients that although they may feel very unwell, serious medical consequences from withdrawal are uncommon and supervision in an inpatient setting is typically not necessary.1 In a minority of individuals withdrawal can be associated with suicidal ideation.16

A variety of support options are available to assist people undergoing methamphetamine withdrawal, including phone or text support and home-based withdrawal with help from a Māori health provider or addiction service (see: “Patient information and further assistance”).

Table 1: Time course of symptoms of withdrawal from methamphetamine.1, 16*

Time period Symptoms

First three day

  • Exhaustion
  • Prolonged sleeping
  • Low mood and energy, depression

Severity of symptoms typically reduces over the first two weeks, but may last longer

Symptoms in the first week, ranked most common to least common:

  • Strong cravings to use again
  • Anxiety, irritability, agitation and mood swings
  • Aches and pains
  • Sleep disturbances, insomnia at night, sudden urge to sleep during the day
  • Difficulty concentrating
  • Depression and anhedonia
  • Headaches

Common symptoms experienced up to a month or more:

  • Mood swings
  • Depression and anhedonia
  • Sleep disturbances and tiredness
  • Cravings

* Symptoms may be less severe and resolve quicker in people who have only used methamphetamine occasionally

Pharmacological treatment of withdrawal symptoms should be done with caution

Evidence does not support the use of any currently available pharmacological treatments to improve a person’s chances of quitting methamphetamine or reduce rates of relapse.25 Symptomatic pharmacological treatment of withdrawal symptoms may be considered in patients with severe symptoms that are unable to be managed with other interventions. Providing medicines such as benzodiazepines to people with an existing substance use disorder could lead to further misuse.1 However, people may interpret a prescription to treat their withdrawal symptoms as a measure of acceptance and that their condition is serious enough to warrant treatment, or conversely that withholding a prescription is a form of punishment or disapproval.1 Safeguards can be put in place to help to prevent inappropriate use of medicines (see: Unintentional misuse of prescription medicines bpacnz, Oct 2018)

Guidance in New Zealand recommends that a brief course of treatment with a benzodiazepine during acute withdrawal may be appropriate for people with severe distress or agitation.1 In practice, quetiapine is often used as it is perceived to be more effective than a benzodiazepine in this scenario and less associated with misuse (although quetiapine still poses a risk). Initial doses of quetiapine should be small due to the risk of postural hypotension; a list of cautions can be found here:

The use of an antidepressant such as a SSRI is unlikely to be useful for treating the symptoms of depression associated with withdrawal, as depressive symptoms are worst in the initial few weeks after stopping use and these medicines often require several weeks of dosing to take effect.1 However, if depression persists, or is underlying to the substance misuse, antidepressant treatment is appropriate. N.B. Be aware of the potential for increased suicidal ideation during the methamphetamine withdrawal period, and in addition, an increased risk of serotonin syndrome in people who concurrently take a serotonergic medicine such as an SSRI, SNRI or tramadol with methamphetamine.

Patient information and further assistance:


Thank you to Dr Vicki Macfarlane, Lead Clinician, Medical Detoxification Services, CADS, Waitemata DHB for expert review of this article.

N.B. Expert reviewers are not responsible for the final content of the article.

Published: 8 November 2018 | Updated:

There are currently no comments for this article.

Please login to make a comment.

Made with by the bpacnz team

Partner links