21st March 2024

Gastrointestinal system

Metoclopramide is a dopamine receptor antagonist which can worsen Parkinson’s disease and must be avoided. Domperidone must be used cautiously in those with prolonged QTc and those co-prescribed CYP3A4 inhibitors (clarithromycin and ketoconazole). It is also contraindicated in those with underlying cardiac disease including congestive heart failure because it increases the risk of arrhythmias.

Proton pump inhibitors (PPI) are indicated for uncomplicated peptic ulcer disease and can be used in cases of severe oesophagitis or oesophageal strictures requiring dilation. PPIs are also used for those at risk of bleeding e.g. on antiplatelets, selective serotonin reuptake inhibitors (SSRIs), venlafaxine, corticosteroids and non-steroidal anti-inflammatories (NSAIDs). In the elderly, simple antacids are not for long term use as these do not prevent symptoms but rather only provide temporary relief. Lifestyle advice is encouraged; mainly promoting avoidance of smoking, coffee, chocolate and fatty foods.

In the elderly population with constipation, all constipating agents should be avoided where possible. This includes anticholinergic drugs, oral iron, opioids, verapamil and aluminium antacids. Equally, in cases of diarrhoea, it is important to avoid exacerbating factors such as antimotility drugs, unnecessary PPI (C. difficile risk) and broad-spectrum antibiotics.