The tolerance of Bonefos was assessed by means of a questionnaire completed by 87 (76.3 %) of 114 addressed patients with multiple myeloma who use this drug for prolonged periods. Of 54 patients treated by the oral form 50 % were quite free from complaints, and complaints associated with more than half the administrations was reported by 7.4 % patients. Of 33 patients treated by infusion 57.6 % were quite free from complaints and 9.0 % patients had complaints after more than half the administrations. The most frequent undesirable effect reported by the addressed patients were digestive complaints. The latter were reported by 47.3 % of the total number of patients who had oral treatment and 42.4 % patients who had treatment by the i.v. route, although in both groups this undesirable effect was as a rule observed in less than 50 % administrations of the drugs. As this was not a placebo controlled trial (which in this case would not be possible for ethical reasons), it is important to consider the fact that the etiological cause of complaints could be any of the concurrently administered drugs incl. cytostatics and that the number of digestive complaints caused by clodronate will be smaller. A total of 16.4% patients with the oral form and 18.2 % patients with the intravenous form reported paraesthesias. This emphasizes that it is advisable or rather necessary to ensure calcium and vitamin substitution also in originally normocalcaemic patients. The preference of a 800 mg capsule to two 400 mg capsules was statistically significant.

        Key words: Multiple myeloma - Clodronate - Bisphosphonates