Analgesics for neuropathic pain and opioids may increase the risk of obesity and hypertension, according to new research in PLOS One. “This is the largest study looking at the links between commonly prescribed painkillers and cardiometabolic health,” says lead author Dr Sophie Cassidy, research associate at the Institute of Cellular Medicine, Newcastle University.

The researchers analysed 125,978 people from the UK Biobank who were taking a cardiometabolic drug such as atenolol, ramipril, bendroflumethiazide, losartan, clopidogrel, simvastatin or atorvastatin. Of these, 7,423 also took a prescribed medication for neuropathic pain (e.g. amitriptyline or gabapentin), opioid analgesic or both.

Those taking a cardio-metabolic drug and an opioid analgesic were 95 per cent more likely to be obese, 82 per cent more likely to have a ‘very high risk’ waist circumference (more than 102cm in men and 88cm in women) and 63 per cent more likely to have hypertension than those on cardiometabolic medication only.

Those taking a cardio-metabolic drug and neuropathic pain medication were 46 per cent more likely to be obese, 50 per cent more likely to have a ‘very high risk’ waist circumference and 26 per cent more likely to have hypertension than those on cardiometabolic medication only.

Those taking a cardio-metabolic drug, neuropathic pain medication and an opioid were 87 per cent more likely to be obese, 77 per cent more likely to have a ‘very high risk’ waist circumference and 38 per cent more likely to have hypertension.

The link seems biologically plausible. Opioids, for example, may result in sedation (which reduces physical activity), seem to increase craving for sugar and sweet foods, and disturb sleep. Indeed, 16.4 per cent of patients taking a neuropathic pain medication, 22.5 per cent of those taking opioids and 28.6 per cent of those taking both reported poor sleep (less than six or more than nine hours a night), compared to 8.7 per cent of those on cardiometabolic medication only.

“In the last two decades there has been a significant increase in the number of people being prescribed both opioid and non-opioid medications to treat chronic pain,” says Dr Cassidy.

“We already know that opiates are dependency-forming but this study also found patients taking opiates have the worst health. Obesity rates are much higher and the patients reported sleeping poorly. These results add further weight to calls for these chronic pain medications to be prescribed for shorter periods.”

^{DOI:10.1371/journal.pone.0187982}