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What is it?

Crystal methamphetamine (aka meth) is a stimulant drug that speeds up messages between the brain and the body – basically, it gets us to stepping! It’s a particular type of methamphetamine, which is generally stronger, more addictive and has more harmful side effects than other amphetamines (i.e., speed).

It is usually found as a strong-smelling white or brownish crystal-like powder or as little crystals that look like ice and is also known as crystal meth, ice, shabu, crystal, glass, Tina, and shard. Many people use these words interchangeably, so for simplicity purposes, we will just use the term meth.

Meth is most often smoked or injected. With injecting, there is a risk of contracting blood-borne viruses, such as hepatitis B & C and HIV if needles are shared and the risk of infection at the injecting site. The effects are felt straight away when smoked and about 15-30 seconds after injection. Occasionally it is swallowed or snorted, with the effects being felt within 20 minutes and 5 minutes respectively. The effects can last up to 12 hours.

What are the effects?

High doses of meth or frequent use may result in an episode of ‘ice psychosis’ characterised by bizarre and irrational behaviour, paranoia and hallucinations, or aggressive and violent behaviour. These episodes can last a few days depending on the amount consumed.

  • Feelings of pleasure and confidence
  • Increased alertness and energy
  • Repeating simple things like itching and scratching
  • Enlarged pupils and dry mouth
  • Teeth grinding and excessive sweating
  • Fast heart rate and breathing
  • Reduced appetite
  • Increased sex drive
  • Extreme weight loss due to reduced appetite
  • Restless sleep
  • Dry mouth and dental problems
  • Regular colds or flu
  • Trouble concentrating
  • Breathlessness
  • Muscle stiffness
  • Anxiety, paranoia and violence
  • Depression
  • Heart and kidney problems
  • Increased risk of stroke


If we take a large amount of meth or have a strong batch, it’s possible to overdose. Knowing the signs of overdose helps keeps us and others safe, and when we might need to call an ambulance. Watch out for these symptoms and call 000 in an emergency:


Racing heartbeat and chest pain


Breathing problems


Fits and uncontrolled jerking


Extreme agitation, confusion, clumsiness


Sudden, severe headaches




Stroke or heart attack

Mixing with other drugs

The effects of mixing meth with other drugs – including over-the-counter or prescribed medications can be unpredictable and dangerous. Do not mix methamphetamine with the following medications as it increases the risk of overdose, and even death:

  • Anti-depressant medications (specifically MAOIs)

There are a range of unsafe interactions to be cautious of when mixing meth and other drugs, and they can be found at the Australian Drug Foundation.

HIV Medications

The interactions between meth and antiretroviral medications are not well known. But we did find that the use of meth may impact the efficacy of antiretroviral medications, and in combination with HIV medications, meth may aggravate HIV-associated neurocognitive disorders.

We did find that there was one fatality with someone using meth and taking antiretroviral medications, which included a combination of Saquinavir, Stavudine and Ritonavir.

Furthermore, we also found that protease inhibitors can increase concentrations of meth in the body, which amplifies its effects, both positive and negative, so best to be aware of meth toxicity.

Lastly, Cobicistat may impact the metabolism of meth and increase or decrease its effects, both positive and negative.

The interactions between meth and PrEP and PEP are not well known. There’s currently no evidence to suggest that meth use directly interacts with these medications or reduces their efficacy. We’ll keep looking and update you if any new research comes to light.

To learn about the interactions between specific HIV medications and meth head to Liverpool HIV Drug Interactions Checker.


There’s currently no evidence to suggest that meth use directly reduces the efficacy of HRT. We’ll keep looking and update this information if something new comes to light.

Feminising hormones and anti-androgens can alter the experience of stimulants generally, including meth. It can result in experiencing amplified effects including excess sweating, rapid heart rate and dehydration, and this is more likely with low testosterone levels.

Fluctuations in Oestrogen and Progesterone can change how we respond to stimulants (although studies have been just with cisgender women), and it can affect our state of mind when taking meth.

Oestradiol can contribute to deep vein thrombosis, and meth use has been shown to increase thrombic risk, so best to chat with a healthcare professional to help manage and mitigate the risk.

Progesterone can cause us to feel tired, drowsy or sleepy a couple of hours after taking it, so it can help to schedule when to take it and when to take meth.

As Spironolactone acts as a diuretic, we may need to be extra mindful of keeping our hydration levels up while using meth so that we don’t experience dehydration.

Testosterone can increase irritability, and restlessness and impact our emotions, so we may find changes in our response when taking meth, such as increased sweating and heart rate, and our experiences of irritability and mood swings.

Both Testosterone and meth use can contribute to a condition known as polycythaemia (a high concentration of red blood cells). This may feel like fatigue, weakness, dizziness, or shortness of breath. Chat with a doctor to keep an eye on any blood tests.

For more information about meth head to the Australian Drug Foundation or TripSit.

The information given on this page is not medical advice and should not be relied upon in that way.