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Duromine
Key points about Duromine®
- Duromine is used as weight-loss treatment, together with a healthy, balanced diet and regular exercise as part of an overall weight-loss plan..
- Duromine is also called phentermine.
- Find out how to take it safely and possible side effects.

Duromine is a weight-loss treatment that's used, together with a healthy, balanced diet and regular exercise, as part of an overall weight-loss plan. Duromine suppresses appetite and you may feel full for longer. This can lead to eating fewer calories and losing weight.
Duromine is available only on prescription
To be prescribed Duromine, you must meet certain criteria depending on your body mass index (BMI) and other health conditions you may have. BMI is calculated using your height and weight. Read more about BMI.
- Duromine is used in adults with a body mass index (BMI) of 30 or more.
- It is also used in adults with a BMI of 27 to 29 (overweight) if they have at least one weight-related health problem such as type 2 diabetes, high blood pressure, high cholesterol or obstructive sleep apnoea.
Note: Duromine is not funded in New Zealand, which means you'll have to pay for it yourself.
Weight loss medicines are used for weight loss when lifestyle changes such as healthy diet and exercise haven't been successful on their own. A routine of healthy eating and regular exercise can provide lasting weight loss. However, for some people this isn't enough and weight loss medicines may help. Weight loss medicines are not a ‘quick fix’, but a long term option for managing weight when combined with healthy eating and exercise. Read more about weight loss medicines.
- The usual dose of Duromine is 1 capsule (15 mg or 30mg) once a day in the morning.
- Your doctor will tell you the best dose for you.
- Increasing the dose may not necessarily make you lose more weight or lose weight faster. But if you have a higher dose, you will most likely experience more side effects.
- Always take your Duromine 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.
- Timing: Take Duromine first thing in the morning, at breakfast time so that it does not keep you awake at night. If you take Duromine any later than lunchtime you may have trouble sleeping at night.
- Food: It doesn't matter if you take this medicine before or after food.
- Alcohol: Avoid alcohol while you're taking Duromine. Alcohol can increase your risk of side effects such as dizziness.
- Missed dose: f you forget to take your Duromine dose at breakfast take it no later than lunchtime, or skip the dose you missed and take your next dose at the normal time on the next day. Don't take a double dose to make up for a dose you have missed.
If you have any of the following, please discuss your options with your healthcare provider before taking Duromine as it may not be suitable for you:
- high blood pressure
- heart problems such as angina (chest pain)
- diabetes
- epilepsy
- an overactive thyroid
- glaucoma
- pregnant or breastfeeding.
Here are some things to know when you're taking Duromine. Other things may be important as well, so ask your healthcare provider what you should know about.
- Have regular checkups with your healthcare team: Having regular checkups every few weeks to months with your healthcare team is important when you’re on Duromine. These visits help to monitor how well the medicine is working and to keep an eye out for any side effects or concerns. Treatment shouldn't be continued for more than 16 weeks if you've not lost more than 5% of your initial body weight.
- Taking other medicines: Duromine interacts with other medicines. Tell your healthcare provider or pharmacist about all medicines you're taking including over the counter medicines, herbal and complementary medicines or recreational drugs.
- Ongoing support when taking weight loss medicines: Managing obesity is about losing weight and focusing on building healthier habits, managing related health issues, improving quality of life, and supporting emotional wellbeing. Having a personalised plan tailored to your needs can be a helpful tool to support you on your weight loss journey. Learn more about ongoing support when taking weight loss medicines.
Like all medicines, Duromine can cause side effects, although not everyone gets them. If you're concerned about any symptoms you think might be related to your medicine, talk to your healthcare provider. The following information offers some guidance but doesn't include all possible side effects.
Common side effects
Tell your healthcare provider if they bother you.
- dizziness: If this happens do not drive or use tools or machines.
- increased heart rate
- nausea and vomiting
- dry mouth
- sleeplessness
- nervousness
- diarrhoea (runny poos) and constipation.
Tell your healthcare provider immediately or phone Healthline free on 0800 611 116 if these occur
- Breathlessness, chest pain, fainting or swelling in your legs, or you are not able to exercise as much as usual.
Read more about medicines and side effects and reporting a reaction you think might be a side effect.
The following links have more information on Duromine:
Duromine(external link) Medsafe Consumer Information Sheet
Resources
Apps/tools
References
- Phentermine(external link) NZ Formulary
- Weight loss: the options and the evidence(external link) BPAC, NZ, 2019
Brochures
Medicines and side effects
Healthify He Puna Waiora, NZ, 2024
Health Quality and Safety Commission, NZ, 2019 English, te reo Māori
Credits: Sandra Ponen, Pharmacist, Healthify He Puna Waiora. Healthify is brought to you by Health Navigator Charitable Trust.
Reviewed by: Angela Lambie, Pharmacist, Auckland
Last reviewed:
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