Safety of subcutaneous clodronate and efficacy in hypercalcemia of malignancy: a novel route of administration.

Bisphosphonates have become standard treatment in management of malignancy-induced hypercalcemia and malignant bone pain. One obstacle to the routine use of bisphosphonates in palliative patients is that oral bisphosphonates have low bioavailability and a degree of gastrointestinal toxicity that may explain poor compliance. Intravenous administration can be cumbersome in patients admitted to long-term care settings or at home. We have developed and tested a new way of administering clodronate via subcutaneous infusion. This retrospective cohort study evaluated 150 patients admitted to a tertiary palliative care unit from May 1996 to May 2000 who received 254 subcutaneous infusions of clodronate for hypercalcemia or bony complications. Data were collected by chart review and specifically evaluated site toxicity and biochemistry. There was minimal local toxicity and only 2 infusions needed to be discontinued because of pain at the subcutaneous site. Clodronate showed efficacy in normalizing the serum calcium within 5 days post-infusion in 32 of 43 infusions given for hypercalcemia. This study shows that subcutaneous clodronate is safe and can lower serum calcium levels in malignant hypercalcemia.