Pharmacovigilance of patients with multiple myeloma being treated with bortezomib and/or thalidomide.

In order to evaluate the main adverse effects of drug protocols using bortezomib and/or thalidomide for the treatment of multiple myeloma, we conducted a prospective study. Data were collected through interviews, clinical observation, and from hospital records. A total of 59 patients were included. There was a predominance of females, 36 (61%) vs 23 (39%) males, and of whites, 49 (83.1%) vs 10 (16.9%) blacks. Age ranged from 40 to 94 years, with a median of 65 years (SD=11.6). Regarding staging at diagnosis, 27 (45.7%) patients were in stage III-A, with 12 (20.3%) patients having serum creatinine ≥2 mg/dL. The main adverse effects in the bortezomib treatment group (n=40) were: neutropenia (42.5%), diarrhea (47.5%), and peripheral neuropathy in 60% of cases, with no difference between the iv (n=26) and sc (n=14) administration routes (P=0.343). In the group treated with thalidomide (n=19), 31.6% had neutropenia, 47.4% constipation, and 68.4% peripheral neuropathy. Neutropenia was associated with the use of alkylating agents (P=0.038). Of the 3 patients who received bortezomib in combination with thalidomide, only 1 presented peripheral neuropathy (33.3%). Peripheral neuropathy was the main adverse effect of the protocols that used bortezomib or thalidomide, with a higher risk of neutropenia in those using alkylating agents. Improving the identification of adverse effects is critical in multiple myeloma patient care, as the patient shows improvements during treatment, and requires a rational and safe use of medicines.