Bisphoshonates: Pamidronate Disodium, Alendronic Acid, Risedronate Sodium Etidronate Disodium and Olpadronate

BISPHOSHONATES: PAMIDRONATE DISODIUM (AREDIA^®), ALENDRONIC ACID (FOSAMAX^®), IBANDRONATE, ZOLENDRONATE (ZOMETA^®), RISEDRONATE SODIUM (ACTONEL^®), CLODRONATE (BONEFOS^®), ETIDRONATE DISODIUM (DIDROCAL^®) AND OLPADRONATE

Primary Use

Pamidronate disodium (3-amino-1-hydroxy propy-lidene, disodium salt pentahydrate) inhibits bone resorption in the management of hypercalcemia of malignancy, osteolytic bone metastases of both breast cancer and multiple myeloma and Paget’s disease of the bone.

Clinical Concerns

This class of drug has been reported to cause anterior uveitis and non-specific conjunctivitis. There are case reports of episcleritis, nerve palsy, ptosis, retrobulbar neuritis and yellow vision. We previously reported a case of anterior scleritis and a case of poste-rior scleritis associated with pamidronate use, with-out rechallenge data. The most studied drug in this class, pamidronate, has caused 17 cases of unilateral scleritis and one case of bilateral scleritis. Onset is usually within 6–48 h of intravenous drug adminis-tration. Six patients had positive rechallenge testing, with scleritis recurring after repeat drug exposure. Other ocular side effects with positive rechallenge data include blurred vision, non-specific conjunc-tivitis, ocular pain, bilateral anterior uveitis and episcleritis.

WHO Classification

Certain

•   Blurred vision

•   Ocular irritation

•   Non-specific conjunctivitis

•   Pain

•   Epiphoria

•   Photophobia

•   Anterior uveitis (rare – posterior)

•   Anterior scleritis (rare – posterior)

•   Episcleritis

Probable

•   Periocular, lid and/or orbital edema

Possible

•   Retrobulbar neuritis

•   Yellow vision

•   Diplopia

•   Cranial nerve palsy

•   Ptosis

•   Visual hallucinations

Guidelines for Following Patients

This is the only class of drug proven to cause scle-ritis. Bisphosphonates can cause vision-threatening diseases. The seriousness of these conditions may dictate discontinuation of the drug in some uveitis cases and, in this series, all cases of scleritis. Further guidelines are as follows:

•   If there is ocular pain or persistent decrease in vision, the patient should see an ophthalmologist.

•   Bilateral anterior uveitis or, rarely, posterior or bilateral uveitis may occur and can vary markedly in severity. Many cases require intensive topical ocular or systemic medication. In some instances, the drug must be discontinued for the uveitis to resolve.

•   Episcleritis may require topical ocular medication; however, pamidronate may be continued.

•   In this series, for the scleritis to resolve, even on full medical therapy, the intravenous pamidronate had to be discontinued.