6 Interactions found for:
Drug Interactions
No drug interactions were found for selected drugs: levothyroxine, Lipitor.
This does not necessarily mean no interactions exist. Always consult your healthcare provider.
Drug and Food Interactions
Moderate
Levothyroxine
+ Food
The following applies to the ingredients: Levothyroxine
The timing of meals relative to your oral levothyroxine dose can affect the absorption of the medication. Therefore, levothyroxine should be taken on a consistent schedule with regard to time of day and relation to meals to avoid large fluctuations in blood levels, which may alter its effects. In addition, absorption of levothyroxine may be decreased and/or delayed by foods such as soybean flour, cotton seed meal, walnuts, dietary fiber, calcium, calcium fortified juices and grapefruit or grapefruit juice. These foods should be avoided within several hours of dosing if possible. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.
The following applies to the ingredients: Levothyroxine
Using multivitamin with minerals together with levothyroxine may decrease the effects of levothyroxine. You should separate the administration of levothyroxine and multivitamin with minerals by at least 4 hours. If your doctor does prescribe these medications together, you may need a dose adjustment or special test to safely use both medications. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.
Moderate
Lipitor
+ Food
The following applies to the ingredients: Atorvastatin (found in Lipitor)
Grapefruit juice can increase the blood levels of atorvastatin. This can increase the risk of side effects such as liver damage and a rare but serious condition called rhabdomyolysis that involves the breakdown of skeletal muscle tissue. In some cases, rhabdomyolysis can cause kidney damage and even death. You should limit your consumption of grapefruit juice to no more than 1 quart per day during treatment with atorvastatin. Let your doctor know immediately if you have unexplained muscle pain, tenderness, or weakness during treatment, especially if these symptoms are accompanied by fever or dark colored urine. You should also seek immediate medical attention if you develop fever, chills, joint pain or swelling, unusual bleeding or bruising, skin rash, itching, loss of appetite, fatigue, nausea, vomiting, dark colored urine, and/or yellowing of the skin or eyes, as these may be signs and symptoms of liver damage. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.
Drug and Pregnancy Interactions
Major
Lipitor
+ Pregnancy
The following applies to the ingredients: Atorvastatin (found in Lipitor)
Professional Content
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
Levothyroxine
+ Pregnancy
The following applies to the ingredients: Levothyroxine
Professional Content
Use is considered acceptable
AU TGA pregnancy category: A
US FDA pregnancy category: Not Assigned
Risk Summary: No increased rates of major birth defects or miscarriages have been reported with use during pregnancy; untreated hypothyroidism during pregnancy is associated with risks to the mother and fetus
Comments:
-Thyroid replacement therapy should not be discontinued during pregnancy; hypothyroidism diagnosed during pregnancy should be promptly treated.
-Monitor TSH levels and adjust doses as needed.
Animal studies have not been conducted. There is a long history of using this drug in pregnant women and this experience has not shown increased rates of fetal malformations, miscarriages or other adverse maternal or fetal outcomes. Hypothyroidism during pregnancy is associated with a higher rate of complications, including spontaneous abortion, pre-eclampsia, stillbirth and premature delivery. Maternal hypothyroidism may have an adverse effect on fetal neurocognitive development. Pregnant women taking this drug should have their TSH measured during each trimester and dose adjusted as appropriate. Patients will generally return to their pre-pregnancy dose after delivery. There are no controlled data in human pregnancy.
AU TGA pregnancy category A: Drugs which have been taken by a large number of pregnant women and women of childbearing age without any proven increase in the frequency of malformations or other direct or indirect harmful effects on the fetus having been observed.
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. Synthroid (levothyroxine)." Abbott Pharmaceutical PROD (2002):
- Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
- Pharmaceutical Society of Australia "APPGuide online. Australian prescription products guide online. http://www.appco.com.au/appguide/default.asp" (2006):
- Cerner Multum, Inc. "Australian Product Information." O 0
Drug and Breastfeeding Interactions
Major
Lipitor
+ Breastfeeding
The following applies to the ingredients: Atorvastatin (found in Lipitor)
Professional Content
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
Levothyroxine
+ Breastfeeding
The following applies to the ingredients: Levothyroxine
Professional Content
Use is considered acceptable
Excreted into human milk: Yes
Comments:
-Levothyroxine (T4) is a normal component of human milk; limited data on exogenous replacement doses during breastfeeding have not shown an adverse effect in nursing infants.
-Levothyroxine dose requirements may be increased in the postpartum period compared to prepregnancy requirements in patients with Hashimoto's thyroiditis.
-The presence of thyroid hormone in breast milk does not appear to interfere with neonatal thyroid screening.
References
- "Product Information. Synthroid (levothyroxine)." Abbott Pharmaceutical PROD (2002):
- Jansson L, Ivarsson S, Larsson I, Ekman R "Tri-iodothyronine and thyroxine in human milk." Acta Paediatr Scand 72 (1983): 703-5
- Moller B, Bjorkhem I, Falk O, Lantto O, Lafsson A "Identification of thyroxine in human breast milk by gas chromatography-mass spectrometry." J Clin Endocrinol Metab 56 (1983): 30-4
- Mizuta H, Amino N, Ichihara K, et al. "Thyroid hormones in human milk and their influence on thyroid function of breast-fed babies." Pediatr Res 17 (1983): 468-71
- Hahn HB, Spiekerman AM, Otto R, Hossalla DE "Thyroid function tests in neonates fed human milk." Am J Dis Child 137 (1983): 220-2
- Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
- Pharmaceutical Society of Australia "APPGuide online. Australian prescription products guide online. http://www.appco.com.au/appguide/default.asp" (2006):
- 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):
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: Professional Interactions
Drug Interaction Classification | |
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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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