Rifamycins and Anti-Diabetic Agents: Drug-Drug Interactions

General Tuberculosis (TB) Therapy Information
Developed by Kelly Bujnoch, PharmD Candidate 2011 with the assistance of Regina Tabor, RPh, DPh,

Robert Petrossian and Barbara Seaworth, MD
Many diabetic medications are metabolized via the Cytochrome P450 (CYP450) enzymatic system in

the liver. Rifampin is a potent inducer of the Cytochrome P450 and accounts for many of the drug

interactions that occur during TB therapy.
Rifabutin is a weaker inducer of the Cytochrome P450 system, potentially interacting with some of

the same medications as Rifampin.
Enzyme induction effects can last 2-4 weeks after discontinuation of rifampin. Glucose levels

should be monitored and diabetic medications should be readjusted at the end of treatment.

Biguanide (Metformin) Based

Brand
Glucophage®

Generic
Metformin

Clinical Effect
Decrease Production of glucose by the liver
Decrease Absorption of glucose by intestines
Increase Insulin sensitivity

Rifampin (RIF) Drug-Drug Interactions
None Noted

Recommendations
No contraindications

Brand
Glucovance®

Generic
Glyburide+
Metformin

Clinical Effect
Glyburide:
Increase Secretion of insulin from the pancreas
Metformin:
Decrease Production of glucose by the liver
Decrease Absorption of glucose by intestines
Increase Insulin sensitivity

Rifampin (RIF) Drug-Drug Interactions
Decrease Glyburide levels 39%
Metformin:
None noted

Recommendations
Consider glipizide as first choice sulfonylurea to minimize interactions
Increase monitoring
Consider dose adjustment of antidiabetic agents or alternative glucose control therapy.
Metformin:
No contraindications

Brand
Metaglip®

Generic
Glipizide+
Metformin

Clinical Effect
Glipizide:
Increase Secretion of insulin from the pancreas
Metformin:
Decrease Production of glucose by the liver
Decrease Absorption of glucose by intestines
Increase Insulin sensitivity

Rifampin (RIF) Drug-Drug Interactions
Decrease Glipizide levels 22%
Metformin:
None noted

Recommendations
Consider glipizide as first choice sulfonylurea to minimize interactions
Increase monitoring
Consider dose adjustment of antidiabetic agents or alternative glucose control therapy.
Metformin:
No contraindications

Brand
Janumet®

Generic
Sitagliptin+
Metformin

Clinical Effect
Sitagliptin:
Increase Secretion of insulin from the pancreas delays gastric emptying
Decrease Appetite
Decrease Glucagon release after meals
Metformin:
Decrease Production of glucose by the liver
Decrease Absorption of glucose by intestines
Increase Insulin sensitivity

Rifampin (RIF) Drug-Drug Interactions
May decrease sitagliptin levels
Metformin:
None noted

Recommendations
Sitagliptin:
Increase monitoring; interaction may be minimal and require no adjustments
Metformin:
No contraindications

Sulfonylurea Based

Brand
Micronase®

Generic
Glyburide

Clinical Effect
Increase Secretion of insulin from the pancreas

Rifampin (RIF) Drug-Drug Interactions
Decrease Glyburide levels 39%

Recommendations
Consider glipizide as first choice sulfonylurea to minimize interactions
Increase monitoring
Consider dose adjustment of antidiabetic agents or alternative glucose control therapy.

Brand
Amaryl®

Generic
Glimepiride

Clinical Effect
Increase Secretion of insulin from the pancreas

Rifampin (RIF) Drug-Drug Interactions
Decrease Glimepiride levels 30%

Recommendations
Consider glipizide as first choice sulfonylurea to minimize interactions
Increase monitoring
Consider dose adjustment of antidiabetic agents or alternative glucose control therapy.

Brand
Glucotrol®

Generic
Glipizide

Clinical Effect
Increase Secretion of insulin from the pancreas

Rifampin (RIF) Drug-Drug Interactions
Decrease Glipizide levels 22%

Recommendations
Consider glipizide as first choice sulfonylurea to minimize interactions
Increase monitoring
Consider dose adjustment of antidiabetic agents or alternative glucose control therapy.

Brand
Glucovance®

Generic
Glyburide +
Metformin

Clinical Effect
Glyburide:
Increase Secretion of insulin from the pancreas
Metformin:
Decrease Production of glucose by the liver
Decrease Absorption of glucose by intestines
Increase Insulin sensitivity

Rifampin (RIF) Drug-Drug Interactions
Decrease Glyburide levels 39%
Metformin:
None noted

Recommendations
Consider glipizide as first choice sulfonylurea to minimize interactions
Increase monitoring
Consider dose adjustment of antidiabetic agents or alternative glucose control therapy.
Metformin:
No contraindications

Brand
Metaglip®

Generic
Glipizide+
Metformin

Clinical Effect
Increase Secretion of insulin from the pancreas
Metformin:
Decrease Production of glucose by the liver
Decrease Absorption of glucose by intestines
Increase Insulin sensitivity

Rifampin (RIF) Drug-Drug Interactions
Decrease Glipizide levels 22%
Metformin:
None noted

Recommendations
Consider glipizide as first choice sulfonylurea to minimize interactions
Increase monitoring
Consider dose adjustment of antidiabetic agents or alternative glucose control therapy.
Metformin:
No contraindications

Brand
Avandaryl®

Generic
Pioglitazone +
Glimepiride

Clinical Effect
Pioglitazone:
Increase Insulin sensitivity (body and liver cells)
Glimepiride:
Increase Secretion of insulin from the pancreas

Rifampin (RIF) Drug-Drug Interactions
Decrease Pioglitazone levels 54%
Decrease Glimepiride levels 30%

Recommendations
Pioglitazone:
Increase monitoring
Consider dose adjustment of antidiabetic agents or alternative glucose control therapy.
Consider glipizide as first choice sulfonylurea to minimize interaction
Metformin:
No contraindications

Brand
Duetact®

Generic
Rosiglitazone +
Glimepiride

Clinical Effect
Rosiglitazone:
Increase Insulin sensitivity (body and liver cells)
Decrease Production of glucose by the liver
Increase Cell uptake of glucose
Glimepiride:
Increase Secretion of insulin from the pancreas

Rifampin (RIF) Drug-Drug Interactions
Decrease Rosiglitazone levels 54-65%
Decrease Glimiprde levels 30%

Recommendations
Rosiglitazone:
Increase monitoring
Consider dose adjustment of antidiabetic agents or alternative glucose control therapy.
Consider glipizide as first choice sulfonylurea to minimize interaction
Metformin:
No contraindications

Meglitinide Analogue

Brand
Prandin®

Generic
Repaglinide

Clinical Effect
Increase Secretion of insulin from the pancreas

Rifampin (RIF) Drug-Drug Interactions
Decrease Repaglinide levels 31-57%

Recommendations
Increase monitoring
Consider dose adjustment of antidiabetic agents or alternative glucose control therapy.

Brand
Starlix®

Generic
Nateglinide

Clinical Effect
Increase Secretion of insulin from the pancreas

Rifampin (RIF) Drug-Drug Interactions
Decrease Nateglinide levels 24%

Recommendations
Increase monitoring
Consider dose adjustment of antidiabetic agents or alternative glucose control therapy.

Thiazolidinedione (PPAR ?-Agonist)

Brand
Avandia®

Generic
Rosiglitazone

Clinical Effect
Increase Insulin sensitivity (body and liver cells)
Decrease Production of glucose by the liver
Increase Cell uptake of glucose

Rifampin (RIF) Drug-Drug Interactions
Decrease Rosiglitazone levels 54-65%

Recommendations
Increase monitoring
Consider dose adjustment of antidiabetic agents or alternative glucose control therapy.

Brand
Actos®

Generic
Pioglitazone

Clinical Effect
Increase Insulin sensitivity (body and liver cells)
Decrease Production of glucose by the liver
Increase Cell uptake of glucose

Rifampin (RIF) Drug-Drug Interactions
Decrease Pioglitazone levels 54%

Recommendations
Increase monitoring
Consider dose adjustment of antidiabetic agents or alternative glucose control therapy.

Brand
Duetact®

Generic
Rosiglitazone +
Glimepiride

Clinical Effect
Rosiglitazone:
Increase Insulin sensitivity (body and liver cells)
Decrease Production of glucose by the liver
Increase Cell uptake of glucose
Glimepiride:
Increase Secretion of insulin from the pancreas

Rifampin (RIF) Drug-Drug Interactions
Decrease Rosiglitazone levels 54-65%
Decrease Glimepiride levels 30%

Recommendations
Increase monitoring
Consider dose adjustment of antidiabetic agents or alternative glucose control therapy.
Consider glipizide as first choice sulfonylurea to minimize interaction
Increase monitoring
Consider dose adjustment of antidiabetic agents or alternative glucose control therapy.

Brand
Avandaryl®

Generic
Pioglitazone +
Glimepiride

Clinical Effect
Pioglitazone:
Increase Insulin sensitivity (body and liver cells)
Glimepiride:
Decrease Secretion of insulin from pancreas

Rifampin (RIF) Drug-Drug Interactions
Decrease Pioglitazone levels 54%
Decrease Glimepiride levels 30%

Recommendations
Increase monitoring
Consider dose adjustment of antidiabetic agents or alternative glucose control therapy.
Consider glipizide as first choice sulfonylurea to minimize interaction
Increase monitoring
Consider dose adjustment of antidiabetic agents or alternative glucose control therapy.

a-Glucosidase Inhibitor

Brand
Precose®

Generic
Acarbose

Clinical Effect
Decrease Digestion and absorption of glucose by the intestines

Rifampin (RIF) Drug-Drug Interactions
None Noted

Recommendations
No contraindications

Brand
Glyset®

Generic
Miglitol

Clinical Effect
Decrease Digestion and absorption of glucose by the intestines

Rifampin (RIF) Drug-Drug Interactions
None Noted

Recommendations
No contraindications

Incretin Mimetic (GLP-1 Receptor Agonist)

Brand
Byetta®

Generic
Exenatide

Clinical Effect
Increase Secretion of insulin from the pancreas delays gastric emptying
Decrease Appetite
Decrease Glucagon release after meals

Rifampin (RIF) Drug-Drug Interactions
None Noted

Recommendations
No contraindications

Dipeptidyl Peptidase IV Inhibitor

Brand
Januvia®

Generic
Sitagliptin

Clinical Effect
Increase Secretion of insulin from the pancreas delays gastric emptying
Decrease Appetite
Decrease Glucagon release after meals

Rifampin (RIF) Drug-Drug Interactions
May decrease sitagliptin levels

Recommendations
Increase monitoring; interaction may be minimal and require no adjustments

Brand
Onglyza®

Generic
Saxagliptin

Clinical Effect
increase Secretion of insulin from the pancreas delays gastric emptying
Decrease Appetite
Decrease Glucagon release after meals

Rifampin (RIF) Drug-Drug Interactions
May decrease saxagliptin levels

Recommendations
Increase monitoring; interaction may be minimal and require no adjustments

Brand
Janumet®

Generic
Sitagliptin +
Metformin

Clinical Effect
Sitagliptin:
Increase Secretion of insulin from the pancreas delays gastric emptying
Decrease Appetite
Decrease Glucagon release after meals
Metformin:
Decrease Production of glucose by the liver
Decrease Absorption of glucose by intestines
Increase Insulin sensitivity

Rifampin (RIF) Drug-Drug Interactions
May decrease sitagliptin levels
Metformin:
None noted

Recommendations
Sitagliptin:
Increase monitoring; interaction may be minimal and require no adjustments
Metformin:
No contraindications

Amylinomimetic

Brand
Symlin®

Generic
Pramlintide

Clinical Effect
Delays gastric emptying
Decrease Appetite
Decrease Glucagon release after meals

Rifampin (RIF) Drug-Drug Interactions
None Noted

Recommendations
No contraindications

References
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pharmacokinetics, pharmacodynamics, and safety of the prandial glucose regulator repaglinide. J

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pharmacokinetics of pioglitazone. Br J Clin Pharmacol, 61 (2006), pp. 70–78
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