6 Interactions found for:
Drug Interactions
No drug interactions were found for selected drugs: Lipitor, metformin.
This does not necessarily mean no interactions exist. Always consult your healthcare provider.
Drug and Food Interactions
Major
Metformin
+ Food
The following applies to the ingredients: Metformin
GENERALLY AVOID: Alcohol can potentiate the effect of metformin on lactate metabolism and increase the risk of lactic acidosis. In addition, alcohol may cause hypoglycemia or hyperglycemia in patients with diabetes. Although hypoglycemia rarely occurs during treatment with metformin alone, the risk may increase with acute consumption of alcohol. Even modest amounts can lower blood sugar significantly, especially when the alcohol is ingested on an empty stomach or following exercise. The mechanism involves inhibition of both gluconeogenesis as well as the counter-regulatory response to hypoglycemia. Episodes of hypoglycemia may last for 8 to 12 hours after ethanol ingestion. By contrast, chronic alcohol abuse can cause impaired glucose tolerance and hyperglycemia. Moderate alcohol consumption generally does not affect blood glucose levels in patients with well controlled diabetes.
Food may have varying effects on the absorption of metformin from immediate-release versus extended-release formulations. When a single 850 mg dose of immediate-release metformin was administered with food, mean peak plasma concentration (Cmax) and systemic exposure (AUC) decreased by 40% and 25%, respectively, and time to peak plasma concentration (Tmax) increased by 35 minutes compared to administration under fasting conditions. By contrast, administration of extended-release metformin with food increased AUC by 50% without affecting Cmax or Tmax, and both high- and low-fat meals had the same effect. These data may not be applicable to formulations that contain metformin with other oral antidiabetic agents.
MANAGEMENT: Metformin should be taken with meals, and excessive alcohol intake should be avoided during treatment. Diabetes patients in general should avoid consuming alcohol if their blood glucose is not well controlled, or if they have hypertriglyceridemia, neuropathy, or pancreatitis. Alcohol should not be consumed on an empty stomach or following exercise, as it may increase the risk of hypoglycemia. Patients should contact their physician immediately if they experience potential signs and symptoms of lactic acidosis such as malaise, myalgia, respiratory distress, increasing somnolence, and nonspecific abdominal distress (especially after stabilization of metformin therapy, when gastrointestinal symptoms are uncommon). With more marked acidosis, there may also be associated hypothermia, hypotension, and resistant bradyarrhythmias. Metformin should be withdrawn promptly if lactic acidosis is suspected. Serum electrolytes, ketones, blood glucose, blood pH, lactate levels, and blood metformin levels may be useful in establishing a diagnosis. Lactic acidosis should be suspected in any diabetic patient with metabolic acidosis lacking evidence of ketoacidosis (ketonuria and ketonemia).
References
- "Product Information. Glucophage (metformin)." Bristol-Myers Squibb PROD (2001):
- "Position Statement: evidence-based nutrition principles and recommendations for the treatment and prevention of diabetes related complications. American Diabetes Association." Diabetes Care 25(Suppl 1) (2002): S50-S60
Moderate
Lipitor
+ Food
The following applies to the ingredients: Atorvastatin (found in Lipitor)
GENERALLY AVOID: Coadministration with grapefruit juice may increase the plasma concentrations of atorvastatin. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. When a single 40 mg dose of atorvastatin was coadministered with 240 mL of grapefruit juice, atorvastatin peak plasma concentration (Cmax) and systemic exposure (AUC) increased by 16% and 37%, respectively. Greater increases in Cmax (up to 71%) and/or AUC (up to 2.5 fold) have been reported with excessive consumption of grapefruit juice (>=750 mL to 1.2 liters per day). Clinically, high levels of HMG-CoA reductase inhibitory activity in plasma is associated with an increased risk of musculoskeletal toxicity. Myopathy manifested as muscle pain and/or weakness associated with grossly elevated creatine kinase exceeding ten times the upper limit of normal has been reported occasionally. Rhabdomyolysis has also occurred rarely, which may be accompanied by acute renal failure secondary to myoglobinuria and may result in death.
ADJUST DOSING INTERVAL: Fibres such as oat bran and pectin may diminish the pharmacologic effects of HMG-CoA reductase inhibitors by interfering with their absorption from the gastrointestinal tract.
MANAGEMENT: Patients receiving therapy with atorvastatin should limit their consumption of grapefruit juice to no more than 1 liter per day. Patients should be advised to promptly report any unexplained muscle pain, tenderness or weakness, particularly if accompanied by fever, malaise and/or dark colored urine. Therapy should be discontinued if creatine kinase is markedly elevated in the absence of strenuous exercise or if myopathy is otherwise suspected or diagnosed. In addition, patients should either refrain from the use of oat bran and pectin or, if concurrent use cannot be avoided, to separate the administration times by at least 2 to 4 hours.
References
- Richter WO, Jacob BG, Schwandt P "Interaction between fibre and lovastatin." Lancet 338 (1991): 706
- McMillan K "Considerations in the formulary selection of hydroxymethylglutaryl coenzyme a reductase inhibitors." Am J Health Syst Pharm 53 (1996): 2206-14
- "Product Information. Lipitor (atorvastatin)." Parke-Davis PROD (2001):
- Boberg M, Angerbauer R, Fey P, Kanhai WK, Karl W, Kern A, Ploschke J, Radtke M "Metabolism of cerivastatin by human liver microsomes in vitro. Characterization of primary metabolic pathways and of cytochrome P45 isozymes involved." Drug Metab Dispos 25 (1997): 321-31
- Bailey DG, Malcolm J, Arnold O, Spence JD "Grapefruit juice-drug interactions." Br J Clin Pharmacol 46 (1998): 101-10
- Lilja JJ, Kivisto KT, Neuvonen PJ "Grapefruit juice increases serum concentrations of atorvastatin and has no effect on pravastatin." Clin Pharmacol Ther 66 (1999): 118-27
- Neuvonen PJ, Backman JT, Niemi M "Pharmacokinetic comparison of the potential over-the-counter statins simvastatin, lovastatin, fluvastatin and pravastatin." Clin Pharmacokinet 47 (2008): 463-74
Drug and Pregnancy Interactions
Major
Lipitor
+ Pregnancy
The following applies to the ingredients: Atorvastatin (found in Lipitor)
According to some authorities: Use is contraindicated during pregnancy or in patients of childbearing potential not using contraception.
AU TGA pregnancy category: D
US FDA pregnancy category: Not assigned
Risk summary: Based on its mechanism of action, this drug may cause fetal harm when administered during pregnancy.
-Available data on the use of statins in pregnant women have not identified a drug-related risk of major congenital malformations and are insufficient to inform a drug-related risk of miscarriage.
Comments:
-If the patient becomes pregnant while taking this drug, therapy should be discontinued and the patient should be apprised of the potential harm to the fetus.
---According to some authorities: Alternatively, the ongoing needs of the individual patient should be considered.
-According to some authorities: Patients of childbearing potential should use effective contraception during therapy; this drug should be used in patients of childbearing potential only when they are highly unlikely to conceive and have been informed of the potential.
Animal studies have failed to reveal evidence of embryofetal toxicity or teratogenicity; however, at maternally toxic doses, increased postimplantation loss and decreased fetal body weights have been observed. No adverse developmental effects were observed in pregnant rats or rabbits administered oral doses that resulted in up to 30 and 20 times, respectively, the human exposure at the maximum recommended human dose (MRHD) of 80 mg (based on body surface area [mg/m2]); in rats administered this drug during gestation and lactation, decreased postnatal growth and development delay were observed at doses at least 6 times the MRHD. This drug crosses the rat placenta and reaches levels in the fetal liver equivalent to that of maternal plasma. A study of statin-exposed pregnant women compared to controls did not find a significant teratogenic effect from maternal use of statins in the first trimester, after adjusting for potential confounders. Rare cases of congenital anomalies after intrauterine exposure to HMG-CoA reductase inhibitors have been reported. There are no controlled data in human pregnancy.
Cholesterol and other products of cholesterol biosynthesis are essential components for fetal development (including synthesis of steroids and cell membranes). Because this drug decreases synthesis of cholesterol and possibly other biologically active substances derived from cholesterol, it may cause fetal harm when used during pregnancy.
Treatment of hyperlipidemia is not generally necessary during pregnancy. Since atherosclerosis is a chronic process, discontinuation of lipid-lowering drugs during pregnancy should have little impact on the outcome of long-term primary hypercholesterolemia therapy for most patients.
AU TGA pregnancy category D: Drugs which have caused, are suspected to have caused or may be expected to cause, an increased incidence of human fetal malformations or irreversible damage. These drugs may also have adverse pharmacological effects. Accompanying texts should be consulted for further details.
US FDA pregnancy category Not Assigned: The US FDA has amended the pregnancy labeling rule for prescription drug products to require labeling that includes a summary of risk, a discussion of the data supporting that summary, and relevant information to help health care providers make prescribing decisions and counsel women about the use of drugs during pregnancy. Pregnancy categories A, B, C, D, and X are being phased out.
References
- "Product Information. Lipitor (atorvastatin)." Viatris Specialty LLC SUPPL-81 (2024):
- "Product Information. Atorvaliq (atorvastatin)." Carolina Medical Products Company SUPPL-2 (2024):
- "Product Information. Lipitor (atorvastatin)." Aspen Pharmacare Australia Pty Ltd (2023):
- "Product Information. Lorstat (atorvastatin)." Alphapharm Pty Ltd (2024):
- "Product Information. Lipitor (atorvastatin)." Viatris UK Healthcare Ltd (2024):
- "Product Information. Atorvastatin (atorvastatin)." Rosemont Pharmaceuticals Ltd (2024):
Minor
Metformin
+ Pregnancy
The following applies to the ingredients: Metformin
Benefit should outweigh risk
AU TGA pregnancy category: C
US FDA pregnancy category: Not assigned
Risk Summary: Data are not sufficient to inform a drug-associated risk for major birth defects or miscarriage; published studies have not reported an increased risk. There are risks to the mother and fetus associated with poorly controlled diabetes in pregnancy.
Comments:
-Maternal glucose levels should be well controlled prior to conception and throughout pregnancy to avoid maternal and fetal diabetes-associated risks.
-Premenopausal women should understand the potential for unintended pregnancy with use of this drug as ovulation may occur in some anovulatory women.
Animal studies do not indicate harmful effects with respect to pregnancy, embryo or fetal development, birth or postnatal development. Poorly-controlled diabetes in pregnancy increases the maternal risk for diabetic ketoacidosis, pre-eclampsia, spontaneous abortions, preterm delivery, stillbirth and delivery complications. Poorly controlled maternal diabetes increases the fetal risk for major birth defects, stillbirth, and macrosomia related morbidity. Published evidence suggests this drug has a good safety profile in women with no increased long-term effects in offspring up to 18 months; however, much of the evidence is from observational, small, and/or nonrandomized studies, and therefore data must be interpreted cautiously.
Many experts continue to recommend insulin as the drug of choice for type 1, type 2, and gestational diabetes when diet alone is unsuccessful in controlling blood sugars. The estimated background risk for major birth defects in women with pre-gestational diabetes mellitus with an HbA1C greater than 7 is 6% to 10% and for women with a HbA1C greater than 10, this risk has been reported to be as high as 20% to 25%. In the US, the estimated risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. The estimated risk of miscarriage for pregnant women with diabetes is unknown. There are no adequate and well-controlled studies in pregnant women.
AU TGA pregnancy category C: Drugs which, owing to their pharmacological effects, have caused or may be suspected of causing, harmful effects on the human fetus or neonate without causing malformations. These effects may be reversible. Accompanying texts should be consulted for further details.
US FDA pregnancy category Not Assigned: The US FDA has amended the pregnancy labeling rule for prescription drug products to require labeling that includes a summary of risk, a discussion of the data supporting that summary, and relevant information to help health care providers make prescribing decisions and counsel women about the use of drugs during pregnancy. Pregnancy categories A, B, C, D, and X are being phased out.
References
- "Product Information. Glucophage (metformin)." Bristol-Myers Squibb PROD (2001):
- Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
- Cerner Multum, Inc. "Australian Product Information." O 0
- "Product Information. Fortamet (metformin)." Physicians Total Care (2014):
- "Product Information. Glumetza (metformin)." Biovail Pharmaceuticals Canada (2014):
- "Product Information. Riomet (metformin)." Ranbaxy Pharmaceuticals (2014):
- Lindsay RS, Loeken MR "Metformin use in pregnancy: promises and uncertainties" Diabetologia 60 (2017): 1612-9
- Kelley KW, Carroll DG, Meyer A "A review of current treatment strategies for gestational diabetes mellitus." Drugs Context 4 (2015): epub
Drug and Breastfeeding Interactions
Major
Lipitor
+ Breastfeeding
The following applies to the ingredients: Atorvastatin (found in Lipitor)
Until more data are available, an alternate agent may be preferred, particularly while breastfeeding newborn or preterm infants.
-According to some authorities: Breastfeeding is not recommended during use of this drug.
-According to some authorities: Use is contraindicated.
Excreted into human milk: Unknown
Excreted into animal milk: Yes
Comments:
-Another drug in this class is excreted into human milk.
-Statins (including this drug) decrease synthesis of cholesterol and possibly other biologically active substances derived from cholesterol; they may cause harm to the breastfed infant.
-The effects in the nursing infant are unknown; based on the mechanism of action, there is the potential for serious adverse reactions in nursing infants.
Due to a concern over disruption of infant lipid metabolism, it is generally agreed that women taking a statin should not breastfeed; however, others have argued that children homozygous for familial hypercholesterolemia are treated with statins starting at 1 year of age, statins have low oral bioavailability, and risks to the breastfed infant are low. Some evidence indicates that this drug can be taken by nursing mothers with no obvious developmental problems in their infants.
In cases of patients with homozygous familial hypercholesterolemia, 6 patients breastfed 11 infants after restarting statin therapy postpartum; the specific statin was not reported, but most of the women on statin therapy were using this drug (40 or 80 mg/day). Normal early child development was reported for all offspring; children started school at the appropriate age with no learning difficulties reported.
References
- Bethesda (MD): National Institute of Child Health and Human Development (US) "Atorvastatin - Drugs and Lactation Database (LactMed) https://www.ncbi.nlm.nih.gov/books/NBK501361/" (2024):
- "Product Information. Lipitor (atorvastatin)." Viatris Specialty LLC SUPPL-81 (2024):
- "Product Information. Atorvaliq (atorvastatin)." Carolina Medical Products Company SUPPL-2 (2024):
- "Product Information. Lipitor (atorvastatin)." Aspen Pharmacare Australia Pty Ltd (2023):
- "Product Information. Lorstat (atorvastatin)." Alphapharm Pty Ltd (2024):
- "Product Information. Lipitor (atorvastatin)." Viatris UK Healthcare Ltd (2024):
- "Product Information. Atorvastatin (atorvastatin)." Rosemont Pharmaceuticals Ltd (2024):
Minor
Metformin
+ Breastfeeding
The following applies to the ingredients: Metformin
Benefit should outweigh risk
Excreted into human milk: Yes
Comments:
-Available data have not reported adverse effects in breastfed infants, however, this data is limited.
-Due to this limited data, product manufacturers recommend a decision should be made to discontinue nursing or discontinue the drug, considering the importance of the drug to the mother.
-Published data suggest this drug is compatible with breastfeeding; they recommend caution when nursing a newborn or premature infant, and those with renal impairment.
Drug levels are expected to be 0.5% (range 0.11% to 1%) of the mother's weight-adjusted dosage and milk/plasma ratio range between 0.13 and 1. Since milk levels are expected to be relatively constant, timing of breastfeeding with drug administration is expected to be of little benefit. One large prospective study found no adverse effects in breastfed infants. Low detectable serum levels were found in some breastfed infants.
References
- "Product Information. Glucophage (metformin)." Bristol-Myers Squibb PROD (2001):
- Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
- Feig DS, Briggs GG, Koren G "Oral antidiabetic agents in pregnancy and lactation: a paradigm shift?" Ann Pharmacother (2007): 1174-80
- Cerner Multum, Inc. "Australian Product Information." O 0
- United States National Library of Medicine "Toxnet. Toxicology Data Network. http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?LACT" (2013):
- "Product Information. Fortamet (metformin)." Physicians Total Care (2014):
- "Product Information. Glumetza (metformin)." Biovail Pharmaceuticals Canada (2014):
- "Product Information. Riomet (metformin)." Ranbaxy Pharmaceuticals (2014):
- Kelley KW, Carroll DG, Meyer A "A review of current treatment strategies for gestational diabetes mellitus." Drugs Context 4 (2015): epub
Therapeutic Duplication Warnings
No warnings were found for your selected drugs.Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.
Switch to: Consumer Interactions
Drug Interaction Classification | |
---|---|
These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication. |
|
Major | Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit. |
Moderate | Moderately clinically significant. Usually avoid combinations; use it only under special circumstances. |
Minor | Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan. |
Unknown | No interaction information available. |
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