Just as all medicines have side effects, they all tend to have contraindications and cautions. Pioglitazone is not to be used in patients with heart failure, bladder cancer or osteoporosis. DPP-4 inhibitors and GLP-1 mimetics should not be used in patients with a history of pancreatitis. And metformin should not be used in people with an eGFR <30ml/minute.

Polypharmacy 

When medicines are added to a patient’s treatment regimen, it is important to check what other medicines the patient is taking. This is not just to rule out contraindications and interactions, but also to determine whether the drug is replacing something that is ineffective or is seeking to treat a potential side effect. Patients should confirm that they are actually taking medicines as prescribed and someone sould check if these are on the list of repeat medicines. It is also important to monitor use of OTC medicines, borrowed medicines, herbal or homeopathic remedies and nutritional supplements. 

The more medicines a patient takes, the greater the risk of side effects, interactions and other medicines-related problems, including confusion.