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Pharmacotherapy for obesity

Obesity is a serious, chronic, relapsing disease of energy regulation, with strong genetic and early-life environmental determinants. 

Medications can be useful adjunct to lifestyle intervention in effecting and maintaining clincially significant weight loss in those with BMI >30, or 27-30 and obesity-related complications. 

*Check BMI here.

Safety and efficacy should be monitored closely on commencement and the medication should be discontinued if there are safety or tolerability issues, or if <5% weight loss is observed after 3-4 months

For the majority of patients, following the exemplary diet and exercise recommendation provide only modest or no weight loss and difficulty to sustain. 

Drug

Starting dose

Available doses

Weight loss vs placebo (% or kg)

Side Effects

Contraindications

 

Phentermine

15 mg

15, 30, 40 mg

3.6-4.5 kg in 6 months

Insomnia, dry mouth, agitation, tachicardia

Hypertension, glaucoma, history drug/alcohol abuse, SSRI antidepressants, pregnancy, heart disease

 

orlistat

120 mg TDS

120 mg

2.9-3.4% in 1 year

Steatorrhea, oil spotting, flatulence, incontinence, vitamin malabsorption

pregnancy

 

Liraglutide

0.6 mg

0.6 – 3

5.4% in 1 year

Nausea, Rare pancreatitis, cholecystitis

Renal/hepatic insufficiency, pregnancy, psychiatric disorder, past pancreatitis

 

Naltrexone/Bupropion

8/90 mg

 

4.8% in 1 year

Nausea, headache, dizzy and dry mouth

Antidepressants,

 

topiramate

12.5 mg mane

25, 50, 100 mg

3.4-5 kg

Insomnia, dry mouth, paraesthesia, altered taste, dizziness, depression

Glaucoma, renal stones, pregnancy

Off label

Phentermine/topiramate

15 mg/12.5 mg mane

15/12.5- 100 mg

5-6.6% in 1 year

As above

As above

Off label

Metformin

500 mg

500-2000 mg

0.6-1.2 kg

Bloating, diarrhea, Vit B12 deficiency, hypoglycemia

Renal problems

Off label

SGLT-2 (dapagliflozin, canagliflozin, empagliflozin)

 

1.8 – 2.7 kg

 

Genital and urinary tract infections

Renal problems

Off label