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What are they?

Amphetamines are a class of stimulant drugs which means that they speed up the messages between the brain and the body. There are legal and illegal usages of amphetamines. The legal ones are typically used to treat ADHD among other conditions. Illegal amphetamines are typically used to boost energy and can come in pill, powder, crystal and capsule form.

The illegal forms of amphetamines, such as speed or ice (aka uppers, up, goeys, whiz, and rack), are often mixed with other drugs that range in size and colour, from pink to white to brown and have a strong smell and a bitter taste.


Amphetamines can be snorted, smoked, eaten, or injected. With injecting, there is risk of contracting blood borne viruses, such as hepatitis B & C and HIV if needles are shared. There is the risk of infection at the injecting site.

What are the effects?

If amphetamines are injected or smoked, their effects are more likely to be felt immediately. If eaten or snorted, they may take up to 30 minutes to take effect.

  • Happiness and confidence
  • Talking more and feeling energetic
  • Large pupils and dry mouth
  • Fast heartbeat and breathing
  • Teeth grinding
  • Reduced appetite
  • Increased sex drive
  • Reduced appetite and extreme weight loss
  • Restless sleeps
  • Dry mouth
  • Dental problems
  • Regular colds and flu
  • Anxiety and paranoia
  • Depression
  • Increased risk of stroke

Psychosis is known to be induced in those using amphetamines for an extended period of time (think days long binges) and can be identified by paranoia, hallucinations and violent and aggressive behaviours. These symptoms usually stop once the use of amphetamines have left the body.


If we take a large amount or a strong batch of amphetamines, 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




Passing out or breathing difficulties


Chills or fever


Not being able to urinate


Arching of the back






Heart attack

Mixing with other drugs

The effects of mixing amphetamines with other drugs – including over the counter or prescribed medications can be unpredictable and dangerous. Do not mix amphetamines 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 amphetamines and other drugs, and they can be found at the Australian Drug Foundation.

HIV Medications

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

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

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

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

The interactions between amphetamines and PrEP and PEP are not well known. There’s currently no evidence to suggest that amphetamine 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 amphetamines head to Liverpool HIV Drug Interactions Checker.


Feminising hormones and anti-androgens can alter the experience of stimulants generally, including amphetamines. 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 amphetamines.

Oestradiol can contribute to deep vein thrombosis, and amphetamine 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 amphetamines.

As Spironolactone acts as a diuretic, we may need to be extra mindful of keeping our hydration levels up while using amphetamines 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 amphetamines, such as increased sweating and heart rate, and our experiences of irritability and mood swings.

Both Testosterone and amphetamine 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 amphetamines 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.