The Inevitable Harms of Weight Loss Drugs

The European Union is investigating the reports of suicidal thoughts associated with the use of weight loss drugs Ozempic® (semaglutide) and Saxenda® (liraglutide). 

The U.S. FDA has received 60 reports of suicidal ideation for patients on semaglutide and 70 on liraglutide. 

Yet, Boris Johnson called semaglutide a “wonder drug” in his first Mail article as a columnist that he hoped would stop his fridge raids. Not a jot about the harm, though.

However, we previously showed in a systematic review that of 25 weight loss drugs approved by regulatory agencies between 1994 and 2003, all were subsequently withdrawn, mainly because of psychiatric or cardiovascular adverse drug reactions. Deaths were reportedly associated with seven products. 

The obsession with blockbuster weight loss drugs subsequently resulted in the development and approval of different groups of centrally acting drugs: the combination medications (naltrexone-bupropion and phentermine-topiramate) and lorcaserin.

But not much changed: again, we showed that the benefit-harm profile of these new drugs was no different from previously withdrawn medications with similar mechanisms of action. More participants who took the anti-obesity drugs achieved over 5% reduction in body weight. However, the products increased the risk of adverse events – one reported harm for every 11 people on the drug. A lot of folks also discontinued the medications because of these adverse events.

We later wrote in BMJ Evidence-Based Medicine that locaserin had minimal benefits and ill-defined harms. We weren’t the only ones – medical journal Prescrire had also warned of the unacceptable risks of the drug. It, therefore, wasn’t that surprising when lorcaserin was subsequently withdrawn from the market within a year of our publication because of an increased cancer risk.

We now find ourselves moving on to the next group of drugs – the approval of GLP-1 receptor agonists for weight loss agents – including Ozempic® and Saxenda®. While the evidence suggests that these drugs may promote weight loss, the potential harms of using such products are not extensively reported or investigated. There are hardly any post-marketing trials investigating their possible disadvantages.

While Johnson believed semaglutide could change the lives of millions, we’re not sure whether that is more likely to be through the small weight losses achieved or because of the harm to come. On average, we found that withdrawal of an obesity drug from the market takes about two years following the first report of an adverse reaction. 

We’re waiting to see what happens next, but don’t have much faith in our regulatory system as it is woeful for assessing harms. Most likely the drug will come with a safety warning, but history tells us what comes next is all too predictable.

Igho Onakpoya is a clinician and researcher with expertise in evaluating the benefits and harms of healthcare interventions. Dr. Carl Heneghan is the Oxford Professor of Evidence Based Medicine. This article was first published on Trust The Evidence, which you can subscribe to here.