Beyond bones: Revisiting the role of vitamin D in chronic liver disease

Table 4 Overview of clinical and pharmacological factors negatively impacting vitamin D bioavailability

Clinical factors	Pharmacological factors
Liver dysfunction	Long-term therapy with antiepileptic drugs: Phenytoin, carbamazepine, primidone. These can decrease vitamin D levels and increase the risk of bone health problems
Chronic kidney failure	Orlistat: May reduce the absorption of vitamin D from food and supplements by blocking fat absorption
Inherited disorders of vitamin D metabolism	Corticosteroids: May reduce calcium absorption and impair vitamin D metabolism
Therapy for people with obesity or gastric bypass	Thiazide diuretics: Excessive vitamin D supplementation may cause hypercalcemia because thiazides decrease urinary calcium excretion
Gastrointestinal diseases: Hepatobiliary disease, malabsorption, chronic pancreatitis, celiac disease	Bile acid sequestrants: Cholestyramine and colestipol. They may impair vitamin D absorption