Paracetamol (Acetaminophen) is the most commonly used drug in the world, with a long record of use in acute and chronic pain. In recent years the benefits of paracetamol use in chronic conditions has been questioned, notably in the areas of osteoarthritis and lower back pain. Over the same period, concerns over the long-term adverse effects of paracetamol use have increased, initially in the field of hypertension, but more recently in other areas also. The evidence base for adverse effects of chronic paracetamol use consists of many cohort and observational studies, with few randomised controlled trials that in many cases contradict each other, so these studies must be interpreted with caution. Nevertheless, there are some areas where the evidence for harm is more robust, and if a clinician is starting paracetamol with the expectation of chronic use it might be advisable to discuss these side effects with patients first. In particular, an increased risk of GI bleeding and a small (~4mmHg) increase in systolic BP are adverse effects for which the evidence is particularly strong, and which show a degree of dose dependence. As our estimation of the benefits decreases, an accurate assessment of the harms is ever more important. This review summarises the current evidence on the harms associated with chronic paracetamol use, focusing on cardiovascular disease, asthma and renal injury, and the effects of in utero exposure.
- Journal Article