4.2.3 Special circumstances

As explained above, vitamin D3 is activated principally by the kidney. In kidney disease this activation may fail. In these circumstances, patients may need supplementation with an activated form of vitamin D, such as alfacalcidol. This will require closer monitoring, which will normally be under the guidance of a specialist physician. A specialist should be consulted about giving vitamin D to patients with eGFR

• renal stones
• hyper/hypocalcaemia
• hyperparathyroidism
• sarcoidosis
• lymphoma
• metastatic cancer
• active TB
• skeletal deformity
• chronic liver disease
• malabsorption (e.g. coeliac disease)