Systematic review and meta-analysis involving 30,000 patients reveals success of weight loss agents
The review published in JAMA looked at five medications approved for management of obesity in the US: orlistat, liraglutide, phentermine-topiramate, lorcaserin, and naltrexone-bupropion.
Only orlistat (Xenical) and liraglutide (Saxenda) are approved in Australia.
Among overweight or obese adults, each of the medications was associated with achieving at least 5% weight loss at 52 weeks, compared with placebo.
Liraglutide, along with phentermine-topiramate, was one of the medications associated with the highest odds of achieving at least 5% weight loss.
According to the TGA, liraglutide is indicated as an adjunct to a reduced calorie diet and increased physical activity for weight management in overweight and obese patients.
The medication is administered subcutaneously, with pre-filled pens delivering doses of eight 0.6mg, 1.2mg, 1.8mg, 2.4mg and 3mg.
The TGA suggests that if a patient on the 3mg/day dose has not lost at least 5% of their initial body weight after 12 weeks, it should be discontinued, since long-term safety data is limited.
Orlistat (Xenical) is available over the counter in Australia, although the TGA reports it is commonly associated with gastrointestinal effects.
Recently registered in the US but not yet in Australia, phentermine-topiramate is shown to be effective for weight loss but also has a high chance of causing significant adverse effects.
A 2014 Australian study published in the MJA found it was “not well tolerated” by the majority of patients due to symptoms paraesthesia, cognitive effects, dry mouth and depression.
However, for the 30% of participants who continued on the drug over the two-year trial, mean weight decreased by 6.7kg and this loss was maintained.
“In those able to continue with pharmacotherapy, the combination was efficacious for both maintenance of weight loss and ongoing weight loss,” the researchers found.