Weight reduction drugs are intended to be used as an adjunct to diet and exercise for weight management in obesity adults. The individuals should meet the criteria of body mass index (BMI) over 30kg/m², or BMI over 27kg/m² with at least one weight-related comorbidity (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia) under doctor’s prescription and supervision.
Registered drugs for the treatment of obesity in Hong Kong are listed as below:
Drug
Function
Side-effects
Usage
Phentermine
Inhibit appetite
Increased heart rate, high blood pressure, dizziness, tremor, nausea
Serious side effects include severe pulmonary vascular disease and heart problems
Oral
Approved for short-term use only (3 months or below)
Orlistat
Prevent digestion and absorption of fat in our body
Serious side effects include seizures, neuropsychiatric disturbances and hepatotoxicity
Oral
Liraglutide
Inhibit appetite Increase satiety
Improve insulin and glucagon regulation
Nausea, vomiting, diarrhoea, constipation
Serious side effects include acute pancreatitis and acute gallbladder disease
Daily subcutaneous injection
Semaglutide
Inhibit appetite Increase satiety
Improve insulin and glucagon regulation
Nausea, vomiting, diarrhoea, constipation
Serious side effects include acute pancreatitis and acute gallbladder disease
Weekly subcutaneous injection
Tirzepatide
Inhibit appetite Increase satiety
Improve insulin and glucagon regulation
Regulate lipolysis
Nausea, vomiting, diarrhoea, constipation
Serious side effects include acute pancreatitis and acute gallbladder disease
Weekly subcutaneous injection
Reminder
Be aware of buying slimming products from the market.
There are many slimming products in the market. Some of these products are not registered as western drugs and have not been properly researched on their safety, efficacy and quality. People who want to take medications to treat obesity should consult medical professionals and should not use any unevaluated product from the market.
Drug treatment is only effective when used in conjunction with lifestyle modification
Current research on drug treatment for obesity has shown that drug treatment together with lifestyle modification have a better outcome in weight reduction. Drug treatment is not a substitute for lifestyle modification and it is strongly recommended that people initiating drug treatment be fully adherent to a healthy lifestyle in order to maximise their chance of successful weight reduction.
Drugs for weight reduction Q & A
According to a survey conducted by the Hong Kong Association for the Study of Obesity in 2018, 67.3% interviewees worried about the side-effects of drugs for treating obesity. Many people have the same question, are those drugs safe?
Q：Are those drugs safe? A：In clinical evaluation of drugs for the treatment of obesity, drugs that had severe side-effects were prohibited for further development and distribution. All the currently approved medications have been fully evaluated in clinical trials to demonstrate effectiveness and an acceptable safety profile. Furthermore, these drugs are prescribed by a doctor and are deemed safe to use after a medical assessment. Glucagon-like peptide 1 receptor agonists (GLP-1 RA), a relatively new class of drug, has been approved for use in the treatment of obesity. This drug helps manage our body weight while having minimal side-effects. By altering the hormonal system, it increases the body’s sense of fullness, reduces the sign of hunger, and helps control our food intake in long-term. If the individual also exercises regularly, the weight loss effect would be more substantial.
Q：Can we use those drugs for the long term? A：Not all the approved drugs can be used long-term. Long-term usage of phentermine may have adverse effects on the heart and lungs and is not recommended for long-term weight management.
