- pregnant patients or prisoners - history of gi bleeding or peptic ulcer disease, or spontaneous bleeding from other sites; history of thrombocytopenia; history of chronic kidney disease; concurrent use of nonsteroidal anti-inflammatory drugs, or steroids. - hypervitaminosis d and associated risk factors: renal failure, liver failure, hyperparathyroidism, sarcoidosis, histoplasmosis

- pregnant patients or prisoners - history of gi bleeding or peptic ulcer disease, or spontaneous bleeding from other sites; history of thrombocytopenia; history of chronic kidney disease; concurrent use of nonsteroidal anti-inflammatory drugs, or steroids. - hypervitaminosis d and associated risk factors: renal failure, liver failure, hyperparathyroidism, sarcoidosis, histoplasmosis