The incidence of gastrointestinal complaints (diarrhea, nausea) is the same for Didronel at 5 mg/kg/day as for placebo, about 1 patient in 15. At 10 to 20 mg/kg/day the incidence may increase to 2 or 3 in 10. These complaints are often alleviated by dividing the total daily dose.
In Paget's patients, increased or recurrent bone pain at pagetic sites, and/or the onset of pain at previously asymptomatic sites has been reported. At 5 mg/kg/day about 1 patient in 10 (versus 1 in 15 in the placebo group) report these phenomena. At higher doses the incidence rises to about 2 in 10. When therapy continues, pain resolves in some patients but persists in others.
No specific adverse reactions.
Worldwide Postmarketing Experience
The worldwide postmarketing experience for etidronate disodium reflects its use in the following approved indications: Paget's disease, heterotopic ossification, and hypercalcemia of malignancy. It also reflects the use of etidronate disodium for osteoporosis where approved in countries outside the US. Other adverse events that have been reported and were thought to be possibly related to etidronate disodium include the following: alopecia; arthropathies, including arthralgia and arthritis; bone fracture; esophagitis; glossitis; hypersensitivity reactions, including angioedema, follicular eruption, macular rash, maculopapular rash, pruritus, Stevens-Johnson syndrome, and urticaria; osteomalacia; neuropsychiatric events, including amnesia, confusion, depression, and hallucination; and paresthesias.
In patients receiving etidronate disodium, there have been rare reports of agranulocytosis, pancytopenia, and a report of leukopenia with recurrence on rechallenge. In addition, there have been rare reports of exacerbation of asthma. Exacerbation of existing peptic ulcer disease including perforation has been reported rarely.
In osteoporosis clinical trials, headache, gastritis, leg cramps, and arthralgia occurred at a significantly greater incidence in patients who received etidronate as compared with those who received placebo.