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Alcohol & Other Drugs

Learn About Methamphetamine


Author: Canadian Institute for Substance Use Research


What is methamphetamine?

Methamphetamine is a psychoactive (mind altering) drug that affects how we think and behave. It is a stimulant that speeds up our breathing, heart rate, thoughts and actions.

Originally a prescription medication, most methamphetamine available today is manufactured in uncontrolled labs using chemicals and other ingredients that may be toxic. It comes in different forms—pills, powder, crystalline chunks called 'crystal meth'—and can be used in different ways: swallowed, snorted, injected, smoked or inserted (in the vagina or rectum).

Why do we use methamphetamine?

Since the 1930s, people have been using methamphetamine for a wide range of reasons. Some people were prescribed the drug to treat conditions such as asthma, depression or obesity. Others have used it to increase their alertness and energy. For instance, some military personnel and shift workers have used methamphetamine to stay awake and perform well on the job. While rarely prescribed today, some people continue to use the drug for fun, to heighten their sexual experiences or to increase their concentration. But like any drug, methamphetamine can be harmful.

When used to help increase our focus and attention, a small amount of methamphetamine may be helpful. But when we use the drug repeatedly, we can start needing an increasing amount in order to feel its positive effects. And while methamphetamine may help us feel more energized in a social situation, continuing to use it as a tool can affect how we engage with others and build relationships.


What happens when we use methamphetamine?

When smoked or injected, methamphetamine moves quickly into our bloodstream and goes directly to the brain. When ingested or inserted, it's absorbed through mucous membranes and takes about 20 minutes to take effect.

Methamphetamine increases naturally occurring chemicals in our brain, activating a series of nerve cells in the brain's "pleasure pathway." We may experience an intense high followed by several hours of energy and contentment. But the effects of methamphetamine can be different for different people. Instead of feeling content, some of us may feel anxious or restless. Some of the factors that can influence how methamphetamine will affect us include our:

  • past experiences with the drug,

  • present mood and surroundings, and

  • mental and physical health condition.

Health effects

Sometimes, when we think about methamphetamine, we forget that it was once commonly prescribed to treat various conditions. This may be because of the risks involved in using the drug today. Because methamphetamine is usually made in uncontrolled laboratories, there is no way to know what's mixed in it. And when we inject or smoke the drug, we are at risk of infections as well as HIV and hepatitis, if sharing needles or pipes.

Small amounts of methamphetamine may make us feel energized and outgoing at a party. Using a large amount to get high very quickly may lessen our control over our behaviour, leading to risk-taking such as having unprotected sex. And using more than moderate amounts may lead to agitation and irritability or overdose.

Regular use of methamphetamine may lead to temporary psychotic symptoms such as seeing things that aren't there. People with a family history of psychosis, or who are living with a psychotic disorder, may be more vulnerable to the long lasting effects. Frequent use of methamphetamine over time can also increase our risk of heart disease and stroke, especially those of us with a cardiac condition. A woman who uses the drug when pregnant may give birth to a baby with a low body weight.

Signs of overdose

Using methamphetamine involves a risk of overdose. How much and how often we use affects our degree of risk. And since it is not possible to know the purity and content of the drug, we can accidentally use too much. Methamphetamine causes the heart to beat faster and blood pressure to rise. Signs of overdose include fast or no pulse, fast or no breathing, hot and sweaty skin, confusion, anxiety, vomiting and seizures.

If someone you know overdoses on methamphetamine, call 911 right away. Remain with the person. If the person is conscious, try to walk them around or keep them awake. If the person is unconscious, roll them onto their side into the recovery position so they won’t choke if they throw up.

Recovery position
  1. Raise person's closest arm above their head. Prepare the person to roll toward you.

  2. Gently roll the person's entire body toward you. Guard their head while you roll them.

  3. Tilt the person's head to keep their airway open. Tuck their nearest hand under their cheek to help keep their head tilted.

recovery position



When is using methamphetamine a problem?

Using methamphetamine is a problem when it negatively affects our life or the lives of others. Many of us may think this refers only to people who regularly use large amounts, but even a single occasion of use can lead to a problem. For instance, if we share pipes or needles, we are at risk of infection. Or using too much might lead us to make poor decisions that result in problems with relationships or the law. What’s important to recognize is the potential for adverse consequences of use in any context and over time.

One consequence that can develop is tolerance. This happens when it takes more of the drug to achieve the positive effects. If we regularly use large amounts of methamphetamine, we are at risk of dependence. This means feeling like we need the drug to function and feel normal.

The reasons people use methamphetamine influence their risk of developing problems. For instance, if a person uses methamphetamine to have fun, only occasional social use may follow. But when a person uses methamphetamine to cope with a long-term problem such as social anxiety, then more long lasting and intense use may follow.

People who develop a dependence on methamphetamine may experience signs of withdrawal, including tiredness, disturbed sleep, headaches, anxiety and depression.

Mixing methamphetamine with other substances

People sometimes mix methamphetamine with other substances to experience different feelings or to offset the effects. For instance, a person may use a sleeping pill to help them relax and rest after using methamphetamine. But combining substances is risky as they can act in unexpected ways. The following are some common combinations and possible results.

Alcohol and other depressants.

These are substances that slow down our heart and make us feel more relaxed. Combining alcohol with methamphetamine increases heart rate more than using methamphetamine alone, increasing the risk of adverse cardiovascular effects. Combining methamphetamine with depressants such as sleeping pills may mask the effects of each drug, potentially leading to risky decisions such as driving a vehicle.

Other stimulants.

These are substances such as tobacco and cocaine that increase our heart rate. Using methamphetamine with other stimulants increases the stress on our cardiovascular system and puts us at risk for experiencing problems such as chest pain, irregular heart rate or overdose.


Combining cannabis with methamphetamine may mask the effects of each drug, potentially clouding our judgment and leading to risky behaviours such as unprotected sex.


When prescription or over-the-counter medications are used with methamphetamine, there is the potential for side effects or for the medicinal benefits to cancel out. Taking the time to read medication labels or consulting with a healthcare professional can reduce these risks.


How to make healthier choices about methamphetamine

Some of the risks of using methamphetamine are related to how we use it. For example, smoking or injecting the drug (or any other drug) can lead to infection and transmission of disease if we share needles or pipes. The following are some other useful guidelines to follow.

Lowering the risks
  • If smoking, wash your hands, start with a small amount, use a shatterproof pyrex pipe and your own mouthpiece, inhale slowly and exhale immediately.

  • If injecting, wash your hands, rotate your injection site but avoid the neck, clean the injection site, use clean needles and never share them.


Not too much. Managing the amount we use in a given period can help to decrease risky behaviours.

Tip: Buy less so you use less, and set a limit to how much you will use at one time.

Not too often. Limiting how often we use helps reduce harms to ourselves and others over time.

Tip: Reflect on your pattern of use and identify the situations in which you are likely to use. And then try to break the pattern by consciously planning other activities for those situations.

Only in safe contexts. Trusting and feeling safe in your surroundings can make injecting or smoking easier and therefore safer.

Tip: Use with a buddy. Using alone means no one will be there to help you if you overdose.


Is methamphetamine legal?

In Canada, it's illegal to make, sell, buy or use methamphetamine. Some BC communities have enacted bylaws to deal with issues related to properties where illegal drugs have been produced. For example, property owners may be required to allow for inspection of the premises and pay the city for the costs to clean up the property.


What to do if you or someone you know wants to explore change

To better understand how substances play a role in your life, visit the You and Substance Use Workbook on the Here to Help website: This website also features detailed information on substance use and mental health.

You can also find information about a wide variety of substance use issues on the Centre for Addictions Research of BC website:


For information on treatment options and resources throughout BC, call the Alcohol and Drug Information and Referral Service at 1-800-663-1441. In Greater Vancouver, call 604-660-9382.


About the author

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The Canadian Institute for Substance Use Research, formerly CARBC, is a member of the BC Partners for Mental Health and Substance Use Information. The institute is dedicated to the study of substance use in support of community-wide efforts aimed at providing all people with access to healthier lives, whether using substances or not. For more, visit


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