Case scenario

Samuel, a 35-year-old male, walks into your pharmacy asking for weight management advice. He is a truck driver, rarely exercises and usually eats takeaways. He weighs 105 kg and is 180 cm tall. He does not take any medicines and has no allergies. He is a non- smoker and enjoys a couple of alcoholic drinks with his evening meals. He has not tried anything for weight loss previously.

Learning objectives 

After reading this article, pharmacists should be able to:

  • Describe non-pharmacological interventions for weight loss
  • Discuss pharmacological treatments for obesity
  • List key adverse effects of pharmacological treatments for obesity. 

Competency (2016) standards addressed: 1.1, 1.3, 1.4, 1.5, 3.1, 3.2, 3.5

Accreditation code: CAP2310CDMSC

Accreditation expiry: 30/09/2026

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Introduction

Obesity is one of the most significant public health concerns worldwide.1 Almost 70% of Australians and 25% of children are overweight or obese.2

Compared to non-obese individuals, the annual cost associated with obesity has been reported to be 19% higher for individuals with a body mass index (BMI) of 30–35 and 51% higher for individuals with a BMI >35.3 Overweight and obesity are defined as complex conditions with excess fat accumulation that predisposes individuals to health risks.1

Community pharmacies are accessible and often the first port of call for health issues.4 Pharmacists have the knowledge and resources to provide tailored solutions for patients’ health and wellbeing.4

Consequences of obesity

Several diseases and disorders related to obesity are contributing factors to early death or disability.5 Such comorbidities include diabetes, hypertension, cancer, osteoporosis, depression, sleep apnoea and infertility.5

Obesity is associated with psychological problems, including low self-esteem, stigma, depression, eating disorders and social isolation.5

Diagnosis 

BMI measures the level of obesity and is calculated using the formula6: BMI = weight (kg)/ height (m2).

Based on the BMI, individuals are considered6:

  • Overweight: BMI 25–29.9
  • Obese type I: BMI 30–34.9
  • Obese type II: BMI 35–39.9
  • Obese type III: BMI ≥40.

Waist circumference (WC) and waist-to-hip ratio (WHR) measure abdominal obesity. A WC of ≥94 cm for men and ≥80 cm for women increases disease risk.5 Men with WHR ≥0.90 cm and women with WHR ≥0.85 cm are at increased risk of obesity-related comorbidities.7

In addition to assessing obesity, pharmacists can inquire about lifestyle, medicines and comorbidities.4 Pharmacists can also help patients set realistic, attainable, measurable and sustainable weight loss goals,8 and advise on self-monitoring, follow-up requirements and available support.4

Causes

Imbalance between energy intake and energy expenditure is the principal cause of obesity.5 Genetic factors may also predispose people to obesity.5 Nutrients and hormones such as gastrointestinal peptides, ghrelin, leptin, cholecystokinin, insulin, glucagon, cortisol and thyroxine regulate food intake by signalling the hypothalamus.9,10 Impaired plasma levels of these nutrients and hormones may contribute to obesity.9,10 Sleep deprivation affects satiety hormones, increasing obesity risk.10 Medical conditions such as Cushing’s syndrome, hypothyroidism and eating disorders increase obesity risk.10

Medicines associated with weight gain include10,11: 

  • Antidepressants: amitriptyline, citalopram, fluoxetine, paroxetine, sertraline
  • Antiepileptics: valproate
  • Antipsychotics: chlorpromazine, clozapine, olanzapine, paliperidone, quetiapine, risperidone
  • Corticosteroids
  • Antidiabetic medicines: insulin, glibenclamide, gliclazide, glimepiride, glipizide
  • Lithium.

Treatment approach

The balance between energy intake and expenditure is the key to weight management. Non-pharmacological interventions can be used alone or with pharmacological interventions for weight management.5

Non-pharmacological interventions

Dietary modification

The calorie requirements of individuals vary depending on gender, age, activity level and medical condition.12 An energy deficit of 500 kcal/day can produce effective weight loss.13 Dietary changes can result in weight loss of up to 5 kg in 12 months5,13 The Australian Dietary Guidelines recommend a diet rich in low-energy foods, fruits and vegetables for weight management.14 Reducing alcohol consumption should be emphasised.14

Low energy diets (LEDs) and very low energy diets (VLEDs)

Within 12 months, VLEDs and LEDs can reduce body weight by 10–15%.15 Combined with lifestyle modifications, they can maintain weight loss for up to 4 years.15 LEDs provide 1200–1600 kcal/day, including meal replacements and structured diet plans.16 A VLED supplies ≤800 kcal/day.13 VLEDs provide a total nutritional replacement for people with a BMI of ≥30 or ≥27 with comorbidities.5,13 VLEDs are contraindicated in pregnancy and breastfeeding and in patients with porphyria, recent myocardial infarction, unstable angina, a history of psychological illness, and alcohol and substance abuse.5,17 Adverse effects associated with VLEDs include:17,18

  • increased sensitivity to cold
  • Dizziness
  • Fatigue
  • Constipation
  • Diarrhoea
  • Muscle cramps
  • Irritability.

VLEDs should be prescribed and supervised by a healthcare practitioner with VLED training.17,19,20 Regular monitoring is required for VLED users on antidiabetic medicines, warfarin, anticonvulsants, lithium, antipsychotics and diuretics.17,18

Physical activity

An active lifestyle increases energy expenditure and improves health outcomes.5 Moderate-intensity physical activity (e.g. brisk walking, gentle swimming, social tennis) for 300 minutes or high-intensity exercise (e.g. running, cycling, boxing) for 150 minutes per week is recommended for weight loss.5

Behavioural change

Long-term changes in diet and physical activity require behavioural modifications.14 Using cognitive behavioural therapy and lifestyle changes, an average weight loss of 5.6 kg can be achieved after 2.8 years.13

Table 1 – Medicines approved for weight management in Australia 

Medicine and dose Mode of action Key adverse effects Key drug interactions Average weight loss (above behavioural intervention alone#) 
Orlistat (capsule)

120 mg three times daily with meals22

 Lipase inhibitor; inhibits absorption of dietary fat22 Flatulence, faecal urgency, steatorrhea, headache, fatigue, malabsorption of fat-soluble vitamins2 Anticoagulants,
cyclosporin, hypoglycaemics, amiodarone, thyroid hormones, combined oral contraceptives22		 4% at 1 year20
Phentermine
(capsule or tablet)15–40 mg once daily23		 Centrally acting adrenaline agonist, appetite suppression17 Restlessness, insomnia, hypertension, palpitations, headache, euphoria, urticaria, rash, diarrhoea23 Monoamine oxidase inhibitors, medicines that can increase blood pressure, medicines that can contribute to serotonin toxicity23 6% at 20 weeks20
Liraglutide

(subcutaneous injection)

0.6 mg daily, increasing
0.6 mg weekly to 3 mg daily24

 GLP-1 receptor agonist; increases glucose-stimulated insulin release, lowers glucagon release, causes appetite suppression, and delays gastric emptying17,18 Nausea, constipation, diarrhoea, headache, cholelithiasis24 Sulfonylureas, insulin24 6% at 1 year20
Semaglutide*

(subcutaneous injection)

0.25 mg weekly, increasing every 4 weeks to 2.4 mg weekly over 16 weeks25

 Same as liraglutide Same as liraglutide Sulfonylureas, insulin26 10.3–12.5% at 68 weeks25

 
Naltrexone + bupropion
(tablet)Initially, 1 tablet once daily in the morning for 1 week, then 1 tablet twice daily for the next week, then 2 tablets
in the morning and 1 tablet in the evening for the third week, then 2 tablets twice daily27		 Bupropion weakly inhibits noradrenaline and dopamine uptake, stimulates pro-opiomelanoortin neurons in the hypothalamus, activates melanocortin receptor, suppresses hunger and elevates energy expenditure. Naltrexone prolongs the action of bupropion28 Nausea, vomiting, headache, constipation, insomnia, dizziness, dry mouth, hypertension29 Monoamine oxidase inhibitorys, CYP2D6 substrates, CYP2B6 inducers, drugs lowering seizure threshold, opioid-containing medicines, some antipsychotics, antidepressants and cardiac medicines29,30 5% at 1 year20
*Not all semaglutide brands are approved for use for weight management in Australia.
# Behavioural interventions used differed between trials.
References: Markovic17, Grima18, Boden20, Sansom22, AMH23, AMH24, TGA25, AMH26, AMH27, Haslam28, TGA29, AMH30

Pharmacological treatments 

Pharmacological interventions may be beneficial for patients with a BMI >30, and a BMI >27 with or at risk of comorbidities and who cannot lose weight with lifestyle interventions.5

In Australia, only five medicines are approved for weight management (see Table 1).21 Available evidence indicates these medicines have similar weight loss efficacy, so the choice of medicine is based on individual factors and preferences.22

Orlistat, a Pharmacist Only medicine, is the only medicine that is approved for long-term weight management in adults.22 The Australian Pharmaceutical Formulary and Handbook (APF) provides detailed guidance about the provision of orlistat.22 Evidence for the effectiveness of complementary medicines such as garcinia cambogia, guarana and green tea is limited or non-existent.22

Bariatric surgery

Bariatric surgery is indicated for people with a BMI >40 or BMI >35 with comorbidities.5 About 20–30% of body weight is lost after bariatric surgery.5 Successful outcomes require long-term follow-up and lifestyle modifications.17,18

Knowledge to practice

Weight loss of about 5–10% of body weight can improve health outcomes for patients with comorbidities, including osteoarthritis, hypertension, sleep apnoea and diabetes.5,17 Pharmacists can initiate a conversation about weight management with patients who may benefit from weight loss by using the 5A’s approach5:

  • Ask if the patient would like to discuss weight management and their weight loss goals.
  • Assess BMI, waist circumference and other comorbidities.
  • Advise on the benefits of maintaining a healthy weight.
  • Assist with weight management interventions; for example, lifestyle interventions, provision of non-prescription medicines.
  • Arrange review and monitoring of weight management and referral to other health professionals.

Conclusion

Obesity is a chronic health issue requiring long-term management. Pharmacists have an important role in providing lifestyle advice and prescription and non-prescription medicines for weight management. Pharmacists can review and monitor patients’ weight management journey and refer to other health professionals for further advice when appropriate.

Case scenario continued 

You calculate his BMI (32.41). You discuss the health benefits of weight reduction and the potential factors contributing to his weight gain. You provide a weight management plan to achieve his attainable and realistic weight loss goal, including dietary advice and physical activity requirements. You provide orlistat according to the guidelines in the APF and advise about dose, adverse effects and monitoring. Samuel feels confident and optimistic about his weight loss journey and improved health outcomes.

Key points

  • Obesity is a chronic condition requiring long-term management.
  • A healthy diet and physical activity are primary interventions for weight loss and maintenance.
  • Pharmacists can play an important role in managing obesity by providing weight management advice and non-prescription treatments, including VLEDs and orlistat, monitoring and referring patients to other health professionals, if necessary.

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References

  1. World Health Organization. Obesity. 2023. At: www.who.int/health-topics/obesity/#tab=tab_1
  2. Australian Institute of Health and Welfare. Overweight and obesity. 2022. At: www.aihw.gov.au/reports/australias-health/overweight-and-obesity
  3. Buchmueller TC, Johar M. Obesity and health expenditures: evidence from Australia. Econ Hum Biol. 2015;17:42-58.
  4. Um IS, Armour C, Krass I, et al. Consumer perspectives about weight management services in a community pharmacy setting in NSW, Australia. Health Expect. 2014;17(4):579-92.
  5. National Health and Medical Research Council. The clinical practice guidelines for the management of overweight and obesity in adults, adolescents and children in Australia. 2013. At: www.nhmrc.gov.au/about-us/publications/clinical-practice-guidelines-management-overweight-and-obesity
  6. Wharton S, Lau DCW, Vallis M, et al. Obesity in adults: A clinical practice guideline. CMAJ. 2020;192(31):E875-e91.
  7. World Health Organization. Waist circumference and waist-hip ratio: Report of a WHO expert consultation Geneva, 8–11 December 2008. 2008. At: www.who.int/publications/i/item/9789241501491
  8. National Institute of Diabetes and Digestive and Kidney Diseases. Talking with patients about weight loss: Tips for primary care providers. 2023. At: www.niddk.nih.gov/health-information/professionals/clinical-tools-patient-management/weight-management/talking-adult-patients-tips-primary-care-clinicians
  9. State Government of Victoria. Obesity and hormones. 2016. At: www.betterhealth.vic.gov.au/health/healthyliving/obesity-and-hormones?trk=public_post_comment-text
  10. Youdim A. Obesity. MSD Manual; [updated 2022 Sept]. At: www.msdmanuals.com/professional/nutritional-disorders/obesity-and-the-metabolic-syndrome/obesity
  11. Louis R, Jenny G. Disease state management: A weighty question. Australian journal of pharmacy. 2011;92(1094):83-7.
  12. State Government of Victoria. Kilojoules and calories. 2021. At: www.betterhealth.vic.gov.au/health/healthyliving/kilojoules-and-calories
  13. Raynor HA, Champagne CM. Position of the academy of nutrition and dietetics: Interventions for the treatment of overweight and obesity in adults. Journal of the Academy of Nutrition and Dietetics. 2016;116(1):129-47.
  14. Australian Government National Health and Medical Research Council. Eat for health Australian dietary guidelines: Providing the scientific evidence for healthier Australian diets. 2013. At: www.eatforhealth.gov.au/guidelines
  15. Brown A, Leeds AR. Very low-energy and low-energy formula diets: Effects on weight loss, obesity co-morbidities and type 2 diabetes remission – an update on the evidence for their use in clinical practice. Nutrition Bulletin. 2019;44(1):7-24.
  16. Moreno B, Bellido D, Sajoux I, et al. Comparison of a very low-calorie-ketogenic diet with a standard low-calorie diet in the treatment of obesity. Endocrine. 2014;47(3):793-805.
  17. Markovic TP, Proietto J, Dixon JB, et al. The Australian obesity management algorithm: A simple tool to guide the management of obesity in primary care. Obesity research & clinical practice. 2022;16(5):353-63.
  18. Grima M. Obesity. Australian Journal for General Practitioners. 2013;42:532-41.
  19. Grima M, Dixon J. Obesity – recommendations for management in general practice and beyond. 2013;42(8):532–41.
  20. Boden collaboration on obesity, nutrition, exercise and eating disorders. Behavioural interventions for adults. Obesity evidence hub; [updated 2020 Aug 26]. At: www.obesityevidencehub.org.au/collections/treatment/behavioural-interventions-for-the-management-of-overweight-and-obesity-in-adults
  21. Walmsley R, Sumithran P. Current and emerging medications for the management of obesity in adults. Medical journal of Australia. 2023;218(6):276-83.
  22. Sansom L N, ed. Australian Pharmaceutical Formulary and Handbook. 25th edn. Canberra: Pharmaceutical Society of Australia; 2021.
  23. Phentermine. In: Australian Medicines Handbook. Adelaide (SA): Australian Medicines Handbook Pty Ltd; 2023. At: https://amhonline.amh.net.au/chapters/psychotropic-drugs/other-psychotropic-drugs/phentermine?menu=hints 
  24. Liraglutide. In: Australian Medicines Handbook. Adelaide (SA): Australian Medicines Handbook Pty Ltd; 2023. At: https://amhonline.amh.net.au/chapters/endocrine-drugs/drugs-diabetes/glucagon-like-peptide-1-analogues/liraglutide?menu=hints
  25. Therapeutic Goods Administration. Australian product information: Wegovy (semaglutide) solution for injection. 2023. At: www.ebs.tga.gov.au/ebs/picmi/picmirepository.nsf/pdf?OpenAgent&id=CP-2022-PI-01930-1
  26. Semaglutide. In: Australian Medicines Handbook. Adelaide (SA): Australian Medicines Handbook Pty Ltd; 2023. At: https://amhonline.amh.net.au/chapters/endocrine-drugs/drugs-diabetes/glucagon-like-peptide-1-analogues/semaglutide?menu=vertical
  27. Naltrexone with bupropion. In: Australian Medicines Handbook. Adelaide (SA): Australian Medicines Handbook Pty Ltd; 2023. At: https://amhonline.amh.net.au/chapters/psychotropic-drugs/other-psychotropic-drugs/naltrexone-bupropion
  28. Haslam D. Weight management in obesity – past and present. International Journal of Clinical Practice. 2016;70(3):206-17.
  29. Therapeutic Goods Administration. Contrave 8/90. 2023. At: https://www.ebs.tga.gov.au/ebs/picmi/picmirepository.nsf/pdf?OpenAgent&id=CP-2019-CMI-01016-1&d=20230409172310101
  30. Drug interactions: Buproprione. In: Australian Medicines Handbook [Internet]. Adelaide (SA): Australian Medicines Handbook Pty Ltd; 2023. At: https://amhonline.amh.net.au/interactions/bupropion-inter

Our author

Swapna Chaudhary (she/her) BPharm(Hons), GradCertAppPharmPrac, MPS is a registered pharmacist practising in a community setting. She is also a PhD candidate and lecturer in pharmacy at James Cook University.

Our reviewer

Sarushka Sritharan (she/her) BPharm(Hons), DipMgt, MPS

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