Background Zolendronic acid infusion is indicated in treatment and prevention of glucocorticoid induced osteoporosis, post-menopausal and male osteoporosis. The infusion is considered safe and well tolerated an even for domiciliary treatment.

Objectives To study acute side effect profile of infusion of Zoledronic Acid (original) versus generic in acute setting

Methods Retrospective data of 222 patients who were prescribed Zoledronic Acid (innovator or generic) over a 3 year period were analyzed to review the acute side effect profile. The 222 patieints laboratory values for serum calcium, creatinine and alkaline phsophatase were found to be normal in all patients.

The infusion time varied between 15-30 minutes. A total of 154 (69.37%) patients received Zoledronic Acid (innovator) infusion and the 68 patients received generic Zoledronic acid infusion. Reinfusion was done in 78 subjects in subsequent year.

Results The common indications of using the infusion were rheumatoid arthritis 58%, lupus 24%, systemic sclerosis 5.4%, other 12.6%. The common side effects in both groups were musculoskeletal followed by nervous system and gastrointestinal. Cardiac and renal were rare. 30% of the patient’s with rheumatoid experienced increasing joint pains after the infusion which lasted for maximum 48 hours. Fever was seen in 44% in the innovator group vs 56% in generic group (p=0.0001). Fever had flu like presentation and usually settled with oral paracetamol. High grade fever (38°C) was less common and was seen in 6.5% in innovator group and 20.6% in generic group (p=0.002). Bony pains, myalgia, arthralgia and back ache were seen more in generic group, however, only arthralgia was statistically significant (p=0.022).

Gastrointestinal systems were seen in 29.8% in innovator and 35.3% in generic. Parasthesias were commonest nervous system complaints seen in both the groups but was not statistically significant (p=0.102). There was one patient who developed renal failure in both the groups. Accelerated hypertension was seen in 1 patient in innovator group and atrial fibrillation was seen in generic group. Reinfusion was associated with 30% lesser side effects as compared to first infusion.

Conclusions The side effect profile was more common in generic (55.88%) than the innovator group (35.06%). As Rheumatoid patients had transient increase in joint pains after infusion they should be counseled for this. Musculoskeletal and GI symptoms are most common after infusion, we would recommend Paracetamol and anti-emetic agents to be added empirically for 48 hours of therapy.

Acknowledgements none

Disclosure of Interest None Declared