Contrave is used as a weight-loss treatment in people with a body mass index (BMI) of 30 or more. Contrave consists of 2 medicines – naltrexone and bupropion.

What is Contrave?

Contrave is used as a weight loss treatment in people with a BMI of 30 or more, together with a healthy, balanced diet and regular exercise, as part of an overall weight-loss plan. BMI is calculated using your height and weight. Learn more about BMI.

It may also be used for people with a BMI of 27 or more if they have at least one weight-related health problem such as high blood glucose levels, high blood pressure, high cholesterol or obstructive sleep apnoea.

Contrave is made up of 2 medicines in each tablet – naltrexone and bupropion. When taken together, they reduce hunger and control food cravings to help you lose weight.


  • In New Zealand Contrave comes as a tablet.  
  • The usual starting dose is 1 tablet in the morning during the first week. The dose is slowly increased over a 4-week period, as follows: 
Week Dose
Week 1 1 tablet in the morning.
Week 2 1 tablet in the morning AND 1 tablet in the evening.
Week 3 2 tablets in the morning AND and 1 tablet in the evening.
Week 4 onwards 2 tablets in the morning AND 2 tablets in the evening.

  • Always take Contrave  exactly as your doctor has told you.
  • The pharmacy label on your medicine will tell you how much to take, how often to take it and any special instructions.

How to take Contrave

  • Swallow the tablets whole; don't crush, chew, or halve tablets.
  • Its best to take Contrave with food.
  • If you forget to take your dose, take it as soon as you remember. But, if it is nearly time for your next dose, just take the next dose at the right time. Don't take double the dose.
  • Do not take Contrave with high-fat meals. It may increase your risk of seizures.
  • Avoid or limit alcohol while you are taking Contrave. Alcohol can increase your risk of side effects such as drowsiness. 
  • Some people don't respond to Contrave. Treatment should not be continued for more than 16 weeks if you have not lost more than 5% of your initial body weight.

Things to consider before taking Contrave

Don't start taking this medicine (and tell your doctor) if you have used opioids within the last 10 days, as it could cause severe withdrawal symptoms. Examples of opioids include codeine, dihydrocodeine, tramadol, morphine, oxycodone, methadone, fentanyl and pethidine. 

If you have any of the following, please discuss your options with your doctor before taking Contrave as it may not be suitable for you:

  • epilepsy or seizures
  • bipolar disorder
  • high blood pressure
  • alcohol or drug withdrawal
  • pregnancy
  • kidney or liver problems.

Things to consider while you are taking Contrave

  • Avoid alcohol while you are taking Contrave, especially when you first start treatment. Alcohol can increase your risk of side effects such as dizziness and drowsiness. 
  • Contrave can affect your concentration. Don't drive or use tools or machinery until you know how this medicine affects you. 
  • Contrave interacts with other medicines. Tell your doctor or pharmacist about all medicines you are taking including over the counter medicines, herbal and complementary medicines or recreational drugs. 

Possible side effects 

Like all medicines, Contrave can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.

Side effects What should I do?
  • Nausea (feeling sick) 
  • This is common in the first month of treatment, but usually goes away with time. 
  • Take Contrave with food.
  • Tell your doctor if this bothers you.
  • Dizziness
  • Dry mouth
  • Constipation
  • Headache
  • This may settle after a few days.
  • Tell your doctor if they bother you.
  • Sleep problems
  • Trouble sleeping  
  • This is quite common and usually goes away with time.
  • It may help to take the evening dose earlier in the day, but at least 8 hours after the morning dose.
  • Tell your doctor if this is ongoing.
  • Mood changes, anxiety, depression, or worsening depression, low mood, aggressive tendencies, thoughts or talk of suicide and self-harm.
  • Tell your doctor immediately or ring Healthline 0800 611 116.
Did you know that you can report a side effect to a medicine to CARM (Centre for Adverse Reactions Monitoring)? Report a side effect to a product.

Learn more

The following links have more information on Contrave:

Contrave Medsafe Consumer Information Sheet, NZ


  1. Naltrexone + bupropion hydrochloride NZ Formulary
  2. Weight loss: the options and the evidence BPAC, NZ, 2022
Credits: Sandra Ponen, Pharmacist. Reviewed By: Angela Lambie, Pharmacist, Auckland Last reviewed: 13 Sep 2022