"What are oral diabetes medications and how do they work?
Insulin is a hormone produced by cells in the pancreas called beta cells. Insulin helps the body use blood glucose (a type of sugar) for energy. People with type 2 diabetes "...
The following adverse reactions are discussed in more detail elsewhere in the labeling:
- Lactic Acidosis [see WARNINGS AND PRECAUTIONS]
- Cardiac Failure [see WARNINGS AND PRECAUTIONS]
- Maj or Adverse Cardiovascular Events [see WARNINGS AND PRECAUTIONS]
- Edema [see WARNINGS AND PRECAUTIONS]
- Weight Gain [see WARNINGS AND PRECAUTIONS]
- Hepatic Effects [see WARNINGS AND PRECAUTIONS]
- Macular Edema [see WARNINGS AND PRECAUTIONS]
- Fractures [see WARNINGS AND PRECAUTIONS]
- Hematologic Effects [see WARNINGS AND PRECAUTIONS]
- Vitamin B12 Levels [see WARNINGS AND PRECAUTIONS]
- Ovulation [see WARNINGS AND PRECAUTIONS]
Clinical Trial Experience
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared with rates in the clinical trials of another drug and may not reflect the rates observed in practice.
Patients With Inadequate Glycemic Control on Diet and Exercise
Table 4 summarizes the incidence and types of adverse reactions without regard to causality reported in a controlled, 32-week, double-blind clinical trial of AVANDAMET in patients with inadequate glycemic control on diet and exercise (N = 468).
Table 4: Adverse Events (≥5% for AVANDAMET)
Reported by Patients With Inadequate Glycemic Control on Diet and Exercise in a
32-Week, Double-blind Clinical Trial of AVANDAMET
N = 155 %
N = 154 %
N = 159 %
|Upper respiratory tract infection||9||7||8|
Mild (no intervention required) to moderate (minor intervention required) symptomatic hypoglycemia was reported by 12% (18/155) of patients treated with AVANDAMET, 14/154 (9%) with metformin, and 8% (13/159) with rosiglitazone. Approximately half of these episodes were accompanied by a simultaneous capillary glucose measurement, and the rate of confirmed hypoglycemia (blood glucose ≤ 50 mg/dL) was low in this clinical trial: 0.6% (1/155) for AVANDAMET, 1.3% (2/154) for metformin, and 0% with rosiglitazone. No hypoglycemic episode led to withdrawal in patients treated with AVANDAMET, and no patients required medical intervention due to hypoglycemia.
The incidence of edema was 6% on AVANDAMET compared with 7% on rosiglitazone and 3% on metformin.
The incidence of anemia was 4% in patients treated with AVANDAMET compared with either rosiglitazone (2%) or metformin (0%).
Patients Inadequately Controlled on Rosiglitazone Monotherapy
The incidence and types of adverse events reported in controlled, 26-week clinical trials of rosiglitazone administered in combination with metformin 2,500 mg/day in comparison with adverse reactions reported in association with rosiglitazone and metformin monotherapies are shown in Table 5. Overall, the types of adverse reactions without regard to causality reported when rosiglitazone was used in combination with metformin were similar to those reported during monotherapy with rosiglitazone.
Table 5: Adverse Events (≥5% for Rosiglitazone
Plus Metformin) Reported by Patients in 26-Week, Double-blind Clinical r
“rials of Rosiglitazone Added to Metformin Therapy
|Preferred Term||Rosiglitazone + Metformin
N = 338 %
N = 2,526 %
N = 601 %
N = 225 %
|Upper respiratory tract infection||16.0||9.9||8.7||8.9|
Reports of hypoglycemia in patients treated with rosiglitazone added to maximum metformin therapy in double-blind trials were more frequent (3.0%) than in patients treated with rosiglitazone (0.6%) or metformin monotherapies (1.3%) or placebo (0.2%). Overall, anemia and edema were generally mild to moderate in severity and usually did not require discontinuation of treatment with rosiglitazone.
Edema was reported in 4.8% of patients receiving rosiglitazone compared with 1.3% on placebo, and 2.2% on metformin monotherapy and 4.4% on rosiglitazone in combination with maximum doses of metformin.
Reports of anemia (7.1%) were greater in patients treated with rosiglitazone added to metformin compared with monotherapy with rosiglitazone. Lower pre-treatment hemoglobin/hematocrit levels in patients enrolled in the metformin and rosiglitazone combination therapy clinical trials may have contributed to the higher reporting rate of anemia in these trials.
Combination With Insulin
The incidence of hypoglycemia (confirmed by fingerstick blood glucose concentration ≤ 50 mg/dL) was 14% for patients on AVANDAMET plus insulin compared with 10% for patients on insulin monotherapy.
The incidence of edema was 7% when insulin was added to AVANDAMET compared with 3% with insulin monotherapy. This trial excluded patients with pre-existing heart failure or new or worsening edema on AVANDAMET. However, in 26-week, double-blind, fixed-dose trials of rosiglitazone added to insulin, edema was reported with higher frequency (rosiglitazone in combination with insulin, 14.7%; insulin, 5.4%) [see WARNINGS AND PRECAUTIONS].
In a trial in which insulin was added to AVANDAMET, no myocardial ischemia was observed in the insulin group (N = 158), and no congestive heart failure was reported in either group. There was one myocardial ischemic event and one sudden death in the group receiving AVANDAMET plus insulin (N = 161). [See WARNINGS AND PRECAUTIONS]
The incidence of anemia was 2% for AVANDAMET in combination with insulin compared with 1% for insulin monotherapy.
Long-term Trial of Rosiglitazone as Monotherapy
A long-term, 4- to 6-year trial (ADOPT) compared the use of rosiglitazone (n = 1,456), glyburide (n = 1,441), and metformin (n = 1,454) as monotherapy in patients recently diagnosed with type 2 diabetes who were not previously treated with antidiabetic medication. Table 6 presents adverse reactions without regard to causality; rates are expressed per 100 patient-years (PY) exposure to account for the differences in exposure to trial medication across the 3 treatment groups.
In ADOPT, fractures were reported in a greater number of women treated with rosiglitazone (9.3%, 2.7/100 patient-years) compared with glyburide (3.5%, 1.3/100 patientyears) or metformin (5.1%, 1.5/100 patient-years). The majority of the fractures in the women who received rosiglitazone were reported in the upper arm, hand, and foot. [See WARNINGS AND PRECAUTIONS] The observed incidence of fractures for male patients was similar among the 3 treatment groups.
Table 6: On-therapy Adverse Events [≥5 Events/100
Patient-years (PY)] in any Treatment Group Reported in a 4- to 6-Year Clinical
Trial of B osiglitazone as Monotherapy (ADOPT)
N = 1,456
PY = 4,954
N = 1,441
PY = 4,244
N = 1,454
PY = 4,906
|Upper respiratory tract infection||4.3||5.0||4.7|
Long-term Trial of Rosiglitazone as Combination Therapy (RECORD)
RECORD (Rosiglitazone Evaluated for Cardiac Outcomes and Regulation of Glycemia in Diabetes) was a multicenter, randomized, open-label, non-inferiority trial in subjects with type 2 diabetes inadequately controlled on maximum doses of metformin or sulfonylurea (glyburide, gliclazide, or glimepiride) to compare the time to reach the combined cardiovascular endpoint of cardiovascular death or cardiovascular hospitalization between patients randomized to the addition of rosiglitazone versus metformin or sulfonylurea. The trial included patients who have failed metformin or sulfonylurea monotherapy; those who failed metformin (n = 2,222) were randomized to receive either add-on rosiglitazone (n = 1,117) or add-on sulfonylurea (n = 1,105), and those who failed sulfonylurea (n = 2,225) were randomized to receive either add-on rosiglitazone (n = 1,103) or add-on metformin (n = 1,122). Patients were treated to target HbA1c ≤ 7% throughout the trial.
The mean age of patients in this trial was 58 years, 52% were male, and the mean duration of follow-up was 5.5 years. Rosiglitazone demonstrated non-inferiority to active control for the primary endpoint of cardiovascular hospitalization or cardiovascular death (HR 0.99, 95% CI: 0.85-1.16). There were no significant differences between groups for secondary endpoints with the exception of congestive heart failure (see Table 7). The incidence of congestive heart failure was significantly greater among patients randomized to rosiglitazone.
Table 7:Cardiovascular (CV) Outcomes for the RECORD
N = 2,220
N = 2,227
|Hazard Ratio||95% CI|
|CV death or CV hospitalization||321||323||0.99||0.85-1.16|
|CV death, myocardial infarction, or stroke||154||165||0.93||0.74-1.15|
There was an increased incidence of bone fracture for subjects randomized to rosiglitazone in addition to metformin or sulfonylurea compared with those randomized to metformin plus sulfonylurea (8.3% versus 5.3%) [see WARNINGS AND PRECAUTIONS]. The majority of fractures were reported in the upper limbs and distal lower limbs. The risk of fracture appeared to be higher in females relative to control (11.5% versus 6.3%), than in males relative to control (5.3% versus 4.3%). Additional data are necessary to determine whether there is an increased risk of fracture in males after a longer period of follow-up.
Decreases in mean hemoglobin and hematocrit occurred in a dose-related fashion in adult patients treated with rosiglitazone (mean decreases in individual trials as much as 1.0 gram/dL hemoglobin and as much as 3.3% hematocrit). The changes occurred primarily during the first 3 months following initiation of rosiglitazone therapy or following an increase in rosiglitazone dose. The time course and magnitude of decreases were similar in patients treated with a combination of rosiglitazone and other hypoglycemic agents or monotherapy with rosiglitazone. Pre-treatment levels of hemoglobin and hematocrit were lower in patients in metformin combination trials and may have contributed to the higher reporting rate of anemia. In a single trial in pediatric patients, decreases in hemoglobin and hematocrit (mean decreases of 0.29 g/dL and 0.95%, respectively) were reported with rosiglitazone. White blood cell counts also decreased slightly in adult 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 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 supplementation.
Serum Transaminase Levels
In pre-approval clinical trials in 4,598 patients treated with rosiglitazone encompassing approximately 3,600 patient-years of exposure, and in a longterm 4- to 6-year trial in 1,456 patients treated with rosiglitazone (4,954 patient-years exposure), there was no evidence of drug-induced hepatotoxicity.
In pre-approval controlled trials, 0.2% of patients treated with rosiglitazone had reversible elevations in ALT >3X the upper limit of normal compared with 0.2% on placebo and 0.5% on active comparators. The ALT elevations in patients treated with rosiglitazone were reversible. Hyperbilirubinemia was found in 0.3% of patients treated with rosiglitazone compared with 0.9% treated with placebo and 1% in patients treated with active comparators. In pre-approval clinical trials, there were no cases of idiosyncratic drug reactions leading to hepatic failure. [See WARNINGS AND PRECAUTIONS]
In the 4- to 6-year ADOPT trial, patients treated with rosiglitazone (4,954 patient-years exposure), glyburide (4,244 patient-years exposure), or metformin (4,906 patient-years exposure) as monotherapy, had the same rate of ALT increase to >3X upper limit of normal (0.3 per 100 patient-years exposure).
In the RECORD trial, patients randomized to rosiglitazone in addition to metformin or sulfonylurea (10,849 patient-years exposure) and to metformin plus sulfonylurea (10,209 patientyears exposure) had a rate of ALT increase to >3X upper limit of normal of approximately 0.2 and 0.3 per 100 patient-years exposure, respectively.
In addition to adverse reactions reported from clinical trials, the events described below have been identified during post-approval use of AVANDAMET or its individual components. Because these events are reported voluntarily from a population of unknown size, it is not possible to reliably estimate their frequency or to always establish a causal relationship to drug exposure.
In patients receiving thiazolidinedione therapy, serious adverse events with or without a fatal outcome, potentially related to volume expansion (e.g., congestive heart failure, pulmonary edema, and pleural effusions) have been reported [see BOXED WARNING, WARNINGS AND PRECAUTIONS].
There are postmarketing reports with rosiglitazone of hepatitis, hepatic enzyme elevations to 3 or more times the upper limit of normal, and hepatic failure with and without fatal outcome, although causality has not been established. There are postmarketing reports with rosiglitazone of rash, pruritus, urticaria, angioedema, anaphylactic reaction, Stevens-Johnson syndrome [see CONTRAINDICATIONS], and new onset or worsening diabetic macular edema with decreased visual acuity [see WARNINGS AND PRECAUTIONS]. (See also GLUCOPHAGE® prescribing information.)
Read the Avandamet (rosiglitazone maleate and metformin hcl) Side Effects Center for a complete guide to possible side effects
Drugs Metabolized By Cytochrome P450
An inhibitor of CYP2C8 (e.g., gemfibrozil) may increase the AUC of rosiglitazone and an inducer of CYP2C8 (e.g., rifampin) may decrease the AUC of rosiglitazone. Therefore, if an inhibitor or an inducer of CYP2C8 is started or stopped during treatment with rosiglitazone, changes in diabetes treatment may be needed based upon clinical response. [See CLINICAL PHARMACOLOGY]
Although drug interactions for metformin with cationic drugs (e.g., amiloride, digoxin, morphine, procainamide, quinidine, quinine, ranitidine, triamterene, trimethoprim, and vancomycin) remain theoretical (except for cimetidine), careful patient monitoring and dose adjustment of AVANDAMET and/or the interfering drug is recommended in patients who are taking cationic medications that are excreted via the proximal renal tubular secretory system. [See WARNINGS AND PRECAUTIONS, CLINICAL PHARMACOLOGY]
Drugs That Produce Hyperglycemia
When drugs that produce hyperglycemia, which may lead to loss of glycemic control, are administered to a patient receiving AVANDAMET, the patient should be closely observed to maintain adequate glycemic control. [See CLINICAL PHARMACOLOGY)
Read the Avandamet Drug Interactions Center for a complete guide to possible interactions
Last reviewed on RxList: 5/28/2014
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