Exenatide

7 DRUG INTERACTIONS • May impact absorption of orally administered medications. ( 7 ) • Warfarin: Postmarketing reports of increased INR sometimes associated with bleeding. Monitor INR frequently until stable upon initiation or alteration of BYETTA therapy. ( 7 ) Generic Section Table 6: Clinically Relevant Interactions with BYETTA Concomitant Use of Insulin Secretagogues or Insulin Clinical Impact Exenatide promotes insulin release from pancreatic beta-cells in the presence of elevated glucose concentrations.

The risk of hypoglycemia is increased when exenatide is used in combination with insulin secretagogues (e.g., sulfonylureas) or insulin [see Warnings and Precautions (5.3) and Adverse Reactions (6) ] . Intervention When initiating BYETTA, consider reducing the dose of concomitantly administered insulin secretagogue or insulin to reduce the risk of hypoglycemia. Warfarin Clinical Impact In a drug interaction study, BYETTA did not have a significant effect on INR [see Clinical Pharmacology (12.3) ] . There have been postmarketing reports for BYETTA of increased INR with concomitant use of warfarin, sometimes associated with bleeding [see Adverse Reactions (6.2) ] .

Intervention In patients taking warfarin, the prothrombin time should be monitored more frequently after initiation or alteration of BYETTA therapy. Once a stable prothrombin time has been documented, the prothrombin time can be monitored at the intervals recommended for patients taking warfarin. Orally Administered Drugs (e.g., acetaminophen) Clinical Impact Exenatide slows gastric emptying. Therefore, BYETTA has the potential to reduce the rate of absorption of orally administered drugs [see Clinical Pharmacology (12.3) ]. Intervention Use caution when administering oral medications with BYETTA where a slower rate of oral absorption may be clinically meaningful.

For oral medications that are dependent on threshold concentrations for efficacy, such as contraceptives and antibiotics, patients should be advised to take those drugs at least 1 hour before BYETTA injection. If such drugs are to be administered with food, patients should be advised to take them with a meal or snack when BYETTA is not administered [see Clinical Pharmacology (12.3) ] .

8.1 Pregnancy Risk Summary Limited data with BYETTA in pregnant women are not sufficient to determine a drug-associated risk for major birth defects or miscarriage. There are risks to the mother and fetus associated with poorly controlled diabetes in pregnancy (see Clinical Considerations ). Based on animal reproduction studies, there may be risks to the fetus from exposure to BYETTA during pregnancy. BYETTA should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Animal reproduction studies identified increased adverse fetal and neonatal outcomes from exposure to exenatide during pregnancy and lactation in association with maternal effects.

In mice, exenatide administered during gestation and lactation caused increased neonatal deaths at systemic exposure 3-times the human exposure resulting from the maximum recommended human dose (MRHD) of 20 mcg/day for BYETTA (see Data ) . The estimated background risk of major birth defects is 6-10% in women with pre-gestational diabetes with an HbA1c >7 and has been reported to be as high as 20-25% in women with HbA1c >10. The estimated background risk of miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively.

Clinical Considerations Disease-associated maternal and/or embryofetal risk Poorly controlled diabetes in pregnancy increases the maternal risk for diabetic ketoacidosis, preeclampsia, spontaneous abortions, preterm delivery, and delivery complications. Poorly controlled diabetes increases the fetal risk for major birth defects, stillbirth, and macrosomia related morbidity. Data Animal Data In studies evaluating reproduction and development in pregnant mice and rabbits, maternal animals were administered exenatide, the active ingredient in BYETTA, by subcutaneous injection twice a day.

In pregnant mice given 6, 68, 460, or 760 mcg/kg/day exenatide during fetal organogenesis, skeletal variations associated with slowed fetal growth, including changes in number of rib pairs or vertebral ossifications sites, and wavy ribs were observed at 760 mcg/kg/day, a dose that produced maternal toxicity and yielded systemic exposure 390-times the human exposure resulting from the MRHD of BYETTA based on AUC comparison. In pregnant rabbits given 0.2, 2, 22, 156, or 260 mcg/kg/day exenatide during fetal organogenesis, irregular fetal skeletal ossifications were observed at 2 mcg/kg/day, a dose yielding systemic…