osteomalacia
3 interactions related to osteomalacia
phenobarbital + vitamin d
Phenobarbital is a strong inducer of liver enzymes that speed the breakdown of vitamin D, so long-term use can lower 25-hydroxyvitamin D and, over months to years, contribute to softened bones (osteomalacia in adults, rickets in children) and higher fracture risk. Children and older or housebound adults are most vulnerable. The drop in vitamin D is well documented; some experimental work also suggests phenobarbital may slow vitamin D activation, though that mechanism rests on animal and cell studies. Have vitamin D and bone-related labs reviewed and discuss ongoing vitamin D with your doctor or pharmacist.
phenytoin + vitamin d
Phenytoin induces the liver enzymes that break down vitamin D, accelerating clearance of 25-hydroxyvitamin D and lowering circulating levels over time. The downstream result can be reduced calcium absorption, a compensatory rise in parathyroid hormone, and an increased risk of softened bones (osteomalacia) and fractures with long-term use.
carbamazepine + vitamin d
Carbamazepine activates the pregnane X receptor and induces the liver enzymes (including CYP3A4 and CYP24A1) that break down vitamin D, accelerating the clearance of 25-hydroxyvitamin D into inactive metabolites. A meta-analysis and observational studies consistently show lower 25(OH)D in long-term carbamazepine users, along with a secondary-hyperparathyroidism pattern and reduced bone density that raises fracture risk over years of therapy.