In 26-week double-blind, fixed-dose studies, edema was reported with higher frequency in the rosiglitazone plus insulin combination trials (insulin, 5.4%; and rosiglitazone in combination with insulin, 14.7%). Reports of new-onset or exacerbation of congestive heart failure occurred at rates of 1% for insulin alone, and 2% (4 mg) and 3% (8 mg) for insulin in combination with rosiglitazone (see WARNINGS, Cardiac Failure and Other Cardiac Effects).
In postmarketing experience with rosiglitazone maleate, adverse events potentially related to volume expansion (e. g., congestive heart failure, pulmonary edema, and pleural effusions) have been reported.
(See also GLUCOPHAGE prescribing information, ADVERSE REACTIONS.)
Decreases in mean hemoglobin and hematocrit occurred in a dose-related fashion in patients treated with rosiglitazone maleate (mean decreases in individual studies up to 1.0 gram/ dL hemoglobin and up to 3.3% hematocrit). The time course and magnitude of decreases were similar in patients treated with a combination of rosiglitazone and other hypoglycemic agents or rosiglitazone monotherapy.
Pre-treatment levels of hemoglobin and hematocrit were lower in patients in metformin combination studies and may have contributed to the higher reporting rate of anemia. White blood cell counts also decreased slightly in patients treated with rosiglitazone. Decreases in hematologic parameters may be related to increased plasma volume observed with rosiglitazone treatment.
In controlled clinical trials of metformin hydrochloride of 29 weeks' duration, a decrease to subnormal levels of previously normal serum vitamin B12 levels, without clinical manifestations, was observed in approximately 7% of patients. Such a decrease, possibly due to interference with B12 absorption from the B12-intrinsic factor complex, is, however, very rarely associated with anemia and appears to be rapidly reversible with discontinuation of metformin or vitamin B12