5 Interactions found for:
Drug Interactions
No drug interactions were found for selected drugs: Fish Oil, levothyroxine.
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.
Drug and Pregnancy Interactions
Major
Fish Oil
+ Pregnancy
The following applies to the ingredients: Omega-3 Polyunsaturated Fatty Acids (found in Fish Oil)
Professional Content
Use is recommended only if clearly needed.
AU TGA pregnancy category: B1
US FDA pregnancy category: Not assigned
Comments:
-There is insufficient data on use in pregnancy to identify drug-associate risks for major birth defects, miscarriage, or adverse fetal or maternal outcomes.
-Animal studies of dams given oral omega-3-acid ethyl esters from mating through lactation did not show adverse reproductive or developmental effects at 5 times the maximum recommended human dose (MRHD).
-Animal studies of oral dosing at clinically relevant doses during organogenesis did not show teratogenicity.
-There is no official RDA for omega-3 fatty acids during pregnancy, but the US Institute of Medicine and the Food and Nutrition Board suggest that 1400 mg per day should be adequate during lactation.
-Pregnant women may not consume adequate amounts of omega-3 fatty acids from their diet due to recommendations to limit fish consumption to no more than twice weekly (due to mercury content of fish).
Animal studies of oral administration from 2 weeks prior to mating through lactation showed no adverse effects at 5 times the recommended human dose (MRHD). A dose ranging study of oral administration from 2 weeks prior to mating to postpartum day 7 showed a 20% reduction in live births and a 40% reduction in pup survival to postnatal day 4 at or above 3000 mg/kg/day (7 times the MRHD). Oral doses up to 14 times the MRHD (a maternotoxic dose) administered during organogenesis showed no fetal adverse effects. Animals given oral doses up to 5 times the MRHD from gestation day 14 through lactation day 21 showed no adverse effects. Skeletal malformations and reduced fetal growth were seen at maternally toxic doses (4 times the MRHD) and embryolethality occurred at 7 times the MRHD in rabbits. There are no controlled data in human pregnancy. Adequate omega-3 fatty acid intake during pregnancy may reduce preterm birth, increase birth length, weight, and head circumference, improve cognitive and visual development, and reduce risk of allergies. The background birth defect and miscarriage risk for the indicated population is not known. In the US general population, the estimated major birth defect risk is 2 to 4% and the miscarriage risk is 15 to 20%.
AU TGA pregnancy category B1: Drugs which have been taken by only a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed. Studies in animals have not shown evidence of an increased occurrence of fetal damage.
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
- Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
- Cerner Multum, Inc. "Australian Product Information." O 0
- "Product Information. Lovaza (omega-3 polyunsaturated fatty acids)." GlaxoSmithKline (2012):
- Briggs GG, Freeman RK. "Drugs in Pregnancy and Lactation." Philadelphia, PA: Wolters Kluwer Health (2015):
- "Product Information. Omega-3-Acid Ethyl Esters (omega-3 polyunsaturated fatty acids)." Apotex Corporation (2017):
- "Product Information. Omega-3 D-3 Wellness Pack (obsolete) (omega-3 polyunsaturated fatty acids)." TMIG Inc (2017):
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
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):
Minor
Fish Oil
+ Breastfeeding
The following applies to the ingredients: Omega-3 Polyunsaturated Fatty Acids (found in Fish Oil)
Professional Content
Safety has not been established; use is not recommended.
Excreted into human milk: Yes
Comments:
-There is no information regarding this drug on the effects on a breastfed infant, or effects on milk production.
-Consider the developmental and health benefits of breastfeeding along with the mother's clinical need for this medication as well as any potential adverse effects from this drug or the underlying maternal condition.
-Higher omega-3 fatty acid levels have been seen in lactating patients receiving oral omega-3 fatty acid supplementation.
-Infant needs for docosahexaenoic acid (DHA) is approximately 70 to 80 mg per day.
-There is no official RDA for omega-3 fatty acids during lactation, but the US Institute of Medicine and the Food and Nutrition Board suggest that 1300 mg per day should be adequate during lactation.
References
- Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
- Briggs GG, Freeman RK. "Drugs in Pregnancy and Lactation." Philadelphia, PA: Wolters Kluwer Health (2015):
- "Product Information. Omega-3-Acid Ethyl Esters (omega-3 polyunsaturated fatty acids)." Apotex Corporation (2017):
- "Product Information. Omega-3 D-3 Wellness Pack (obsolete) (omega-3 polyunsaturated fatty acids)." TMIG Inc (2017):
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 | |
|---|---|
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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