Understanding Weight Loss Medications (Pharmacotherapy)

What Is Pharmacotherapy for Weight Loss?

Weight loss medications — known as pharmacotherapy — are prescription medicines that support weight loss when combined with dietary changes and physical activity. They are not a replacement for healthy lifestyle habits, but they can significantly improve outcomes for patients who have struggled to achieve sustained results through lifestyle changes alone.

Dr Chun Guan Chong will assess whether pharmacotherapy is appropriate for you based on your full medical history, current medications, and health goals.

Who May Benefit from Weight Loss Medications?

Pharmacotherapy is generally considered for adults who:

• Have a BMI of 30 or above, OR
• Have a BMI of 27 or above with a weight-related health condition (type 2 diabetes, high blood pressure, sleep apnoea, or high cholesterol)
• Have made sustained attempts at lifestyle changes without adequate results

A thorough medical assessment is essential before starting any weight loss medication. Medications are not suitable for everyone.

GLP-1 Receptor Agonists

GLP-1 (glucagon-like peptide-1) receptor agonists are currently the most effective class of weight loss medications available. Originally developed to treat type 2 diabetes, they are now approved for chronic weight management.

How they work:

• Reduce appetite by acting on receptors in the brain's hunger and satiety centres
• Slow the rate at which food leaves the stomach (gastric emptying), increasing the feeling of fullness after eating
• Improve insulin secretion and reduce glucagon, helping regulate blood sugar levels

Available medications in Australia:

• Semaglutide (Ozempic / Wegovy) — weekly subcutaneous (under the skin) injection. Clinical trials show average weight loss of 15–17% of body weight over 68 weeks when used alongside lifestyle changes.
• Liraglutide (Saxenda) — daily subcutaneous injection. Average weight loss of approximately 8–10% of body weight.

Common side effects:

• Nausea — the most common side effect, particularly in the first 4–8 weeks. Usually improves as the body adjusts to the medication.
• Vomiting
• Diarrhoea or constipation
• Reduced appetite (this is the intended effect)
• Fatigue in the early weeks

Who should NOT use GLP-1 medications:

• Personal or family history of medullary thyroid cancer
• Multiple endocrine neoplasia type 2 (MEN2)
• History of pancreatitis
• Pregnancy or breastfeeding
• Severe kidney disease (check with Dr Chong)

Starting Medication: What to Expect

Medications are started at a low dose and gradually increased over several weeks to months. This process — called dose titration — minimises side effects by allowing the body to adjust slowly.

During the first 4–8 weeks:

• Nausea is most common and usually improves with time
• Eating smaller, lower-fat meals can significantly reduce nausea
• Staying well hydrated (at least 2 litres of water per day) helps
• Avoid rich, greasy, or spicy foods during the early adjustment period
• Most patients notice reduced appetite within the first few weeks

Monitoring During Treatment

Regular follow-up appointments with Dr Chong are essential during pharmacotherapy. At each review, Dr Chong will monitor:

• Weight and body measurements
• Blood pressure and heart rate
• Blood tests — glucose, HbA1c, lipids, kidney function (at appropriate intervals)
• Side effect management
• Medication dose adjustments

How Long Is Treatment Required?

Weight loss medications are generally intended for long-term use. Obesity is a chronic condition, and like medications for blood pressure or cholesterol, stopping pharmacotherapy often results in gradual weight regain as appetite returns.

The decision to continue, adjust, or stop medication is made together with Dr Chong based on your progress, tolerance, and goals.

Important Safety Reminders

• Never start, stop, or change the dose of weight loss medications without medical advice
• Inform all other healthcare providers that you are taking these medications
• These medications are prescription-only in Australia — avoid unregulated online sources, which may supply counterfeit or unapproved products
• Weight loss medications work best as part of a comprehensive program including dietary guidance, physical activity, and regular medical follow-up