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What is it?

Methadone and BUP (buprenorphine) are prescription opioid drugs used primarily to wean someone off of heroin or other opioids. This process is known as pharmacotherapy and helps with withdrawal symptoms.

Methadone is usually swallowed as a liquid but can be injected or taken in tablet form. BUP can be taken as tablets, films that are dissolved under the tongue or long-acting injections. 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.

What are the effects?

The effects of methadone and BUP last much longer than the effects of heroin or other opioids. A single dose lasts about 24 hours, whereas a dose of heroin may only last a couple of hours.

  • Constipation
  • Headaches
  • Increased sweating
  • Tiredness or drowsiness (especially after a dose)
  • Loss of appetite, nausea and vomiting
  • Abdominal pain
  • Skin rashes, itching or hives
  • Tooth decay
  • Menstruation changes
  • A lowered sex drive
  • Weight gain
  • Sweating
  • Difficulty urinating
  • Constipation
  • Aching muscles and joints
  • Rashes and itching
  • Lethargy, mental clouding and confusion
  • Runny nose
  • Yawning
  • High temperature but feeling cold and sweating with goose bumps
  • Irritability and aggression
  • Loss of appetite, nausea and vomiting
  • Abdominal cramps and diarrhoea
  • Tremors, muscle spasms and jerking
  • Back and joint aches
  • Cravings for the drug they were dependent on


If the methadone dose is too high, 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:


Low and shallow breathing


Slack muscles


Occasional seizures


Drowsiness or unconsciousness


Cold, clammy skin and bluish/greyish colour

Mixing with other drugs

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

  • Ketamine
  • Cocaine
  • Alcohol
  • GHB
  • Benzos

There are a range of unsafe interactions to be cautious of when mixing methadone and BUP with other drugs, and they can be found at TripSit.

HIV Medications

The interactions between methadone/BUP and antiretroviral medications are not well known. There’s currently no evidence to suggest that methadone/BUP use directly reduces the efficacy of antiretroviral medications. If some new research comes to light, then we’ll update this section and let you know.

There is a range of antiretroviral medications, from different categories, that should not be mixed with methadone and/or BUP. Some interactions can cause issues with toxicity in the central nervous system, affect cardiac function, create abnormal rhythm, slow breathing and significant shifts in mental health. The interactions can also lead to increasing or decreasing the effects, and side effects, of methadone and/or BUP.

It’s best to chat with an HIV specialist before taking any form of methadone or BUP.

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


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

Methadone is an opioid and Oestradiol can affect our opioid receptors, and therefore how the body processes it, so it’s best to chat with a healthcare professional about whether our dosage needs to be adjusted.

Spironolactone and opioids can potentially lead to a build-up of toxicity and affect our kidneys.

Progesterone and Cyproterone Acetate can have sedative effects and cause tiredness and fatigue, so taking these along with other depressants may lead to feeling more exhausted during or after using opioids.

Both testosterone and opioids can cause water retention, which means we may experience constipation and bloating when taking both.

We don’t yet know enough about how opioid-induced androgen deficiency (OPIAD) may impact bodies that are taking testosterone, including whether it may impact our absorption or processing of our HRT.

For more information about methadone/BUP 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.