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7 Interactions found for:

Synthroid and Zoloft
Interactions Summary
  • 2 Major
  • 3 Moderate
  • 2 Minor
  • Synthroid
  • Zoloft

Drug Interactions

Moderate
Synthroid + Zoloft

The following applies to the ingredients: Levothyroxine (found in Synthroid) and Sertraline (found in Zoloft)

Professional Content

MONITOR: Limited evidence suggests that sertraline may decrease levothyroxine efficacy in treating hypothyroidism. A study of 9 patients treated with levothyroxine and sertraline, found that the combination was related to elevated serum thyrotropin (TSH) concentrations. However, in another study involving 15 patients treated with levothyroxine and sertraline, no changes were observed in thyrotropin (TSH), thyroxine (T4), free thyroxine and triiodothyronine (T3) parameters as compared to patients who only took levothyroxine. The mechanism of this interaction is not known.

MANAGEMENT: Clinical monitoring of patient response, including laboratory serum TSH concentrations, is recommended. Adjustment of thyroid replacement dosage may be indicated when initiating or discontinuing sertraline therapy.

References

  1. Carvalho GA, Bahls SC, Boeving A, graf h "Effects of Selective Serotonin Reuptake Inhibitors on Thyroid Function in Depressed Patients with Primary Hypothyroidism or Normal Thyroid Function" Thyroid 19 (2009): 7
  2. N Engl J Med "Elevated Serum Thyrotropin in Thyroxine-Treated Patients with Hypothyroidism Given Sertraline" NEJM 337 (1997): 1010-1011
  3. "Product Information. Thyrox (levothyroxine sodium)." Waymade Australia Pty Limited (2023):
  4. "Product Information. Eltroxin (levothyroxine)." Advanz Pharma (2023):
  5. "Product Information. Synthroid (levothyroxine)." AbbVie US LLC (2024):
  6. "Product Information. Levothyroxine Sodium (levothyroxine)." Lannett Company Inc (2024):
  7. "Product Information. Levothyroxine Sodium (levothyroxine)." Zentiva Pharma UK Ltd (2023):
  8. "Product Information. Levothyroxine (Sandoz) (levothyroxine sodium)." Sandoz Pty Ltd (2023):
  9. "Product Information. Liothyronine Sodium (liothyronine)." AvKare Inc (2024):

Drug and Food Interactions

Moderate
Synthroid + Food

The following applies to the ingredients: Levothyroxine (found in Synthroid)

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 (found in Synthroid)

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
Zoloft + Food

The following applies to the ingredients: Sertraline (found in Zoloft)

You should avoid or limit the use of alcohol while being treated with sertraline. Alcohol can increase the nervous system side effects of sertraline such as dizziness, drowsiness, and difficulty concentrating. Some people may also experience impairment in thinking and judgment. Talk to your doctor or pharmacist if you have any questions or concerns.

Drug and Pregnancy Interactions

The following applies to the ingredients: Sertraline (found in Zoloft)

Professional Content

This drug should be used during pregnancy only if the potential benefit outweighs the potential risk to the fetus, taking into account the risks of untreated depression.
-Oral concentrate and solution formulations containing alcohol: Not recommended.

AU TGA pregnancy category: C
US FDA pregnancy category: Not assigned.

Risk summary: Malformative risk is unlikely when given during the first trimester. There is inconclusive data on use of this drug in the third trimester to inform of a drug-related risk.

Comments:
-A pregnancy exposure registry is available.
-Neonates exposed to this drug late in the third trimester may require respiratory support, tube feeding, and/or prolonged hospitalization.
-Exposed neonates should be monitored after delivery for direct toxic effects of this drug, drug discontinuation syndrome, and serotonin syndrome (e.g., respiratory distress, cyanosis, apnea, seizures, temperature instability, feeding difficulty, vomiting, hypoglycemia, hypo/hypertonia, hyperreflexia, tremor, jitteriness, irritability, constant crying).

Animal studies have failed to reveal evidence of teratogenicity; however, there was evidence of delayed ossification and effects on reproduction attributed to maternal toxicity. Decreased neonatal survival following maternal administration at exposures similar to or slightly greater than the maximum recommended human dose of 200 mg was also observed; the clinical significance is unknown. There are no controlled data in human pregnancy.

The results of several studies suggest that the use of SSRIs in the first trimester of pregnancy may be associated with an increased risk of cardiovascular and/or other congenital malformations; however, this association has not been clearly established. The association appears to be strongest for another SSRI, paroxetine.

Use of sertraline during pregnancy has been reported to cause symptoms compatible with withdrawal reactions in neonates whose mothers had taken sertraline. Neonates exposed to SSRIs and SNRIs late in the third trimester have uncommonly reported clinical findings including respiratory distress, cyanosis, apnea, seizures, temperature instability, feeding difficulty, vomiting, hypoglycemia, hypotonia, hyperreflexia, tremor, jitteriness, irritability, and constant crying. These effects have mostly occurred either at birth or within a few days of birth. These features are consistent with either a direct toxic effect of SSRIs and SNRIs, or possibly a drug discontinuation syndrome; in some cases, the clinical picture is consistent with serotonin syndrome. The results of a cohort study indicate that 30% of neonates who had prolonged exposure to SSRIs in utero experience symptoms, in a dose-response manner, of a neonatal abstinence syndrome after birth. The authors suggest that infants exposed to SSRIs should be closely monitored for a minimum of 48 hours after birth.

Epidemiological data have suggested that the use of SSRIs, particularly in late pregnancy, may increase the risk of persistent pulmonary hypertension in the newborn. Data are not available for SNRIs.

One study compared 267 women exposed to an SSRI - either fluvoxamine, paroxetine, or sertraline, to 267 controls. Exposure to SSRIs was not associated with either increased risk for major malformations, higher rates of miscarriage, stillbirth, or prematurity. Mean birth weights among SSRI users were similar to controls as were the gestational ages. The study concluded that the SSRIs fluvoxamine, paroxetine, and sertraline did not appear to increase teratogenic risk when used in their recommended doses.

Animal data with sertraline have not shown an effect on fertility. Human case reports from some SSRIs have shown an effect on sperm quality that is reversible. As yet, the impact of this on human fertility has not been observed.

To monitor maternal-fetal outcomes of pregnant women exposed to antidepressant therapy, a National Pregnancy Registry for Antidepressants has been established. Healthcare providers are encouraged to prospectively register patients. For additional information: https://womensmentalhealth.org/clinical-and-research-programs/pregnancyregistry/antidepressants/

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

  1. "Product Information. Zoloft (sertraline)." Roerig Division PROD (2001):
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  3. Cerner Multum, Inc. "Australian Product Information." O 0

The following applies to the ingredients: Levothyroxine (found in Synthroid)

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

  1. "Product Information. Synthroid (levothyroxine)." Abbott Pharmaceutical PROD (2002):
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  3. Pharmaceutical Society of Australia "APPGuide online. Australian prescription products guide online. http://www.appco.com.au/appguide/default.asp" (2006):
  4. Cerner Multum, Inc. "Australian Product Information." O 0

Drug and Breastfeeding Interactions

The following applies to the ingredients: Sertraline (found in Zoloft)

Professional Content

Use is not recommended; benefit to the mother should outweigh risk to the infant.

Excreted into human milk: Yes

Comments:
-This drug has been considered one of the preferred antidepressants during breastfeeding.
-Accumulation of the drug may occur in preterm infants with impaired metabolic activity; effects similar to neonatal abstinence may rarely present in these infants.
-Mothers taking an SSRI during pregnancy and postpartum may have difficulty breastfeeding and may require additional breastfeeding support.

Benign neonatal sleep myoclonus in a 4-month-old infant and agitation in that spontaneously resolved in another infant was reported to the Australian Adverse Drug Reaction Advisory Committee and may be related to the presence of sertraline in breastmilk.

Levels of sertraline in breastmilk are reported to be low; the weakly active metabolite desmethylsertraline may be detectable in low levels. In a study of 26 breastfeeding women who were, on average, 15.8 weeks postpartum and receiving an average of 124 mg sertraline daily for at least 14 days for severe depression, complete sets of milk sample data were available for 15 mothers. Analysis of these samples led the study authors to estimate that an exclusively breastfed infant would receive an average of 0.54% of the maternal weight-adjusted dosage. Pumping and discarding milk 8 to 9 hours after the mother's dose would decrease the infant's daily dosage by 17%.

Amounts of sertraline ingested by breastfed infants are reported to be small. There was an analysis of 30 breastfed infants aged 6 to 13 weeks, of which 19 were exclusively breastfed and 11 breastfed at least half the time. Serum sertraline levels were below 1 mcg/L in 22 infants. The other 8 infants had an average serum sertraline level of 7.9 mcg/L; their mothers were taking a average of 109 mg sertraline daily, with an average serum level of 52.8 mcg/L.

The data from one study on three breast-fed infants suggested that sertraline and/or its almost inactive metabolite norsertraline may be present at very low concentrations in the plasma of breast-fed infants. No adverse effects were noted in the infants.

A pooled analysis of 53 mother-infant pairs from published and unpublished cases found that infants had an average of 2% of the sertraline plasma levels of the mothers'; three of the infants had a plasma level greater than 10% of the mothers'.

A study of fourteen mother-infant pairs reported that while mothers receiving clinical doses of sertraline experienced substantial blockade of the platelet 5-HT transporter, platelet 5-HT uptake in nursing infants of treated mothers was unaltered.

Another study of twelve breast-feeding mothers reported that both sertraline and desmethylsertraline were present in all breast milk samples. Detectable levels of sertraline were reported in three nursing infants and detectable levels of desmethylsertraline were reported in six infants.

A case study of a mother breast-feeding while receiving sertraline therapy has also been reported. The drug was found to be present in the mother's milk. However, no sertraline was detected in the infant's serum and no abnormal occurrences were noted in the development of this infant either.

References

  1. "Product Information. Zoloft (sertraline)." Roerig Division PROD (2001):
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  3. Cerner Multum, Inc. "Australian Product Information." O 0
  4. United States National Library of Medicine "Toxnet. Toxicology Data Network. http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?LACT" (2013):

The following applies to the ingredients: Levothyroxine (found in Synthroid)

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

  1. "Product Information. Synthroid (levothyroxine)." Abbott Pharmaceutical PROD (2002):
  2. Jansson L, Ivarsson S, Larsson I, Ekman R "Tri-iodothyronine and thyroxine in human milk." Acta Paediatr Scand 72 (1983): 703-5
  3. 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
  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
  5. Hahn HB, Spiekerman AM, Otto R, Hossalla DE "Thyroid function tests in neonates fed human milk." Am J Dis Child 137 (1983): 220-2
  6. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  7. Pharmaceutical Society of Australia "APPGuide online. Australian prescription products guide online. http://www.appco.com.au/appguide/default.asp" (2006):
  8. Cerner Multum, Inc. "Australian Product Information." O 0
  9. 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

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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