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Drug Interactions between lapatinib and Progynova

This report displays the potential drug interactions for the following 2 drugs:

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Interactions between your drugs

Moderate

estradiol lapatinib

Applies to: Progynova (estradiol) and lapatinib

Lapatinib may increase the blood levels and effects of estradiol. You may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications. Contact your doctor if you experience increased side effects or your condition changes. 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 food/lifestyle interactions

Moderate

lapatinib food/lifestyle

Applies to: lapatinib

Take lapatinib on an empty stomach 1 hour before or 1 hour after a meal unless otherwise directed by your doctor. This will make it easier for your body to absorb the medication. The lapatinib dose is administered once daily and should not be divided. The usual dose of lapatinib is equal to 5 tablets. You may swallow each tablet one at a time, but take the entire lapatinib dose at the same time each day. If you are receiving therapy with lapatinib you should be advised to avoid grapefruits and grapefruit juice. Grapefruit can raise the levels of lapatinib in your body and lead to dangerous side effects.

Minor

estradiol food/lifestyle

Applies to: Progynova (estradiol)

Information for this minor interaction is available on the professional version.

Disease interactions

Major

estradiol Abnormal Uterine Bleeding

Applies to: Abnormal Uterine Bleeding

The use of estrogens is contraindicated in patients with undiagnosed, abnormal vaginal bleeding. Prolonged (> 1 year), unopposed estrogen use (i.e. estrogen without concomitant progestin therapy) has been associated with a significant, dose-related risk of endometrial carcinoma. The risk may be offset substantially by the addition of a progestin but may not be completely abolished. Prior to initiating estrogen therapy, appropriate diagnostic tests should be performed in patients with abnormal vaginal bleeding to rule out endometrial malignancy. The same applies if recurrent or persistent bleeding develops during estrogen therapy.

Major

lapatinib Arrhythmias

Applies to: Arrhythmias

QT prolongation was observed in patients treated with certain EGFR inhibitors. These agents should be administered with caution in patients with congenital long QTc syndrome, congestive heart failure, electrolyte abnormalities, or those who are taking medications known to prolong the QTc interval. Serum electrolytes should be corrected prior to initiating therapy with these agents. Periodic monitoring of ECGs and electrolytes is recommended in these patients. Permanently discontinue the use of these agents in patients who develop QTc interval prolongation with signs/symptoms of life-threatening arrhythmia.

Major

estradiol Breast Cancer

Applies to: Breast Cancer

When treated with an estrogen, patients with breast cancer and bone metastases may develop severe hypercalcemia, in which case the drug should be stopped and measures be taken to reduce serum calcium levels.

Major

estradiol Cerebral Vascular Disorder

Applies to: Cerebral Vascular Disorder

The use of estrogens is considered by manufacturers and some authorities to be contraindicated in patients with active thrombotic, thromboembolic, or thrombophilic disorders. The use of estrogen-containing oral contraceptives is additionally deemed contraindicated in patients with a history of such disorders and/or current cerebrovascular or coronary artery disease. Females with a history of migraines with aura are at an increased risk for stroke and this stroke risk may be further increased in females who have migraines with aura with use of combination oral contraceptives. Hypercoagulability and changes in various clotting factors and blood components have been observed in women receiving estrogen therapy. Known preexisting risk factors for increased thromboembolic or cardiovascular events include smoking, especially over age of 35; hypertension; hyperlipidemia; obesity; diabetes; age over 40; and lupus. Therapy with estrogens should be administered cautiously in the lowest effective dosage and only after careful consideration of risks and benefits. Estrogens should be avoided in patients with a history of thrombotic and thromboembolic disorders associated with estrogen use, except when used in the treatment of metastatic breast or prostatic malignancy.

Major

lapatinib Congestive Heart Failure

Applies to: Congestive Heart Failure

QT prolongation was observed in patients treated with certain EGFR inhibitors. These agents should be administered with caution in patients with congenital long QTc syndrome, congestive heart failure, electrolyte abnormalities, or those who are taking medications known to prolong the QTc interval. Serum electrolytes should be corrected prior to initiating therapy with these agents. Periodic monitoring of ECGs and electrolytes is recommended in these patients. Permanently discontinue the use of these agents in patients who develop QTc interval prolongation with signs/symptoms of life-threatening arrhythmia.

Major

lapatinib Dermatitis - Drug-Induced

Applies to: Dermatitis - Drug-Induced

Cutaneous reactions, in some cases severe, have been reported with the use of EGFR inhibitors. Monitor patients who develop dermatologic or soft tissue toxicities while receiving these agents for the development of inflammatory or infectious sequelae. It is recommended to withhold treatment, and appropriate measures should be instituted as appropriate or discontinue the use of these agents for dermatologic or soft tissue toxicity associated with severe or life-threatening inflammatory or infectious complications. Advise patients to wear sunscreen and hats and limit sun exposure while receiving therapy with these agents as exposure to sunlight can exacerbate dermatologic toxicities.

Major

lapatinib Fever

Applies to: Fever

The use of certain EGFR inhibitors has been associated with pulmonary toxicity. Serious cases of interstitial lung disease (ILD), including fatal cases and interstitial pneumonitis or pulmonary fibrosis have been reported. Caution is recommended when using these agents in patients with a history of interstitial pneumonitis or pulmonary fibrosis or those patients presenting with acute onset of new or progressive unexplained pulmonary symptoms such as dyspnea, cough, and fever pending diagnostic evaluation. If ILD is confirmed, permanently discontinue these agents and institute appropriate measures.

Major

estradiol Hepatic Tumor

Applies to: Hepatic Tumor

The use of oral contraceptives is contraindicated in patients with liver tumors. An increased risk of benign hepatic adenomas and hepatocellular carcinomas has been associated with long-term, oral estrogen- progestin contraceptive use of at least 4 years and 8 years, respectively. Although these tumors are rare and have not been reported with other types of estrogen or progestogen therapies, any preparation containing estrogens and/or progestogens should probably be avoided in patients with existing tumors of the liver. Hepatic hemangiomas and nodular hyperplasia of the liver have been reported with isolated estrogen therapy.

Major

estradiol History - Thrombotic/Thromboembolic Disorder

Applies to: History - Thrombotic / Thromboembolic Disorder

The use of estrogens is considered by manufacturers and some authorities to be contraindicated in patients with active thrombotic, thromboembolic, or thrombophilic disorders. The use of estrogen-containing oral contraceptives is additionally deemed contraindicated in patients with a history of such disorders and/or current cerebrovascular or coronary artery disease. Females with a history of migraines with aura are at an increased risk for stroke and this stroke risk may be further increased in females who have migraines with aura with use of combination oral contraceptives. Hypercoagulability and changes in various clotting factors and blood components have been observed in women receiving estrogen therapy. Known preexisting risk factors for increased thromboembolic or cardiovascular events include smoking, especially over age of 35; hypertension; hyperlipidemia; obesity; diabetes; age over 40; and lupus. Therapy with estrogens should be administered cautiously in the lowest effective dosage and only after careful consideration of risks and benefits. Estrogens should be avoided in patients with a history of thrombotic and thromboembolic disorders associated with estrogen use, except when used in the treatment of metastatic breast or prostatic malignancy.

Major

estradiol Hypertension

Applies to: Hypertension

The risk of myocardial infarction and strokes, including those associated with oral contraceptive use and some estrogen use, is increased in patients with hypertension. Moreover, estrogens (and progestogens) may elevate blood pressure and worsen the hypertension, thus compounding the risk. Clinically significant blood pressure increases have been reported during estrogen therapy, particularly in patients receiving high dosages or treated with oral contraceptive combinations having high progestational activity. These effects also increase with duration of therapy and patient age. Therapy with estrogens should be administered cautiously in patients with preexisting hypertension. Some estrogen-based therapies, such as combined hormonal contraceptives, may be contraindicated in patients with uncontrolled hypertension or hypertension with vascular disease. Patients should be monitored for changes in cardiovascular status, and their antihypertensive regimen adjusted or estrogen therapy withdrawn as necessary. In patients requiring contraception, alternative methods should be considered for those who are hypertensive, over age 35, and smoke.

Major

estradiol Ischemic Heart Disease

Applies to: Ischemic Heart Disease

The use of estrogens is considered by manufacturers and some authorities to be contraindicated in patients with active thrombotic, thromboembolic, or thrombophilic disorders. The use of estrogen-containing oral contraceptives is additionally deemed contraindicated in patients with a history of such disorders and/or current cerebrovascular or coronary artery disease. Females with a history of migraines with aura are at an increased risk for stroke and this stroke risk may be further increased in females who have migraines with aura with use of combination oral contraceptives. Hypercoagulability and changes in various clotting factors and blood components have been observed in women receiving estrogen therapy. Known preexisting risk factors for increased thromboembolic or cardiovascular events include smoking, especially over age of 35; hypertension; hyperlipidemia; obesity; diabetes; age over 40; and lupus. Therapy with estrogens should be administered cautiously in the lowest effective dosage and only after careful consideration of risks and benefits. Estrogens should be avoided in patients with a history of thrombotic and thromboembolic disorders associated with estrogen use, except when used in the treatment of metastatic breast or prostatic malignancy.

Major

lapatinib Liver Disease

Applies to: Liver Disease

Lapatinib undergoes extensive metabolism in the liver. Hepatotoxicity has been associated with the use of lapatinib and it may be severe and fatal. The hepatotoxicity may occur days to several months after initiation of treatment. Therapy with lapatinib should be administered cautiously in patients with severe hepatic impairment and a dose reduction should be considered for patients with severe pre-existing hepatic impairment. Clinical monitoring of hepatic function (transaminases, bilirubin, and alkaline phosphatase) is recommended before initiation of treatment, every 4 to 6 weeks during treatment, and as clinically indicated. In patients who develop severe hepatotoxicity while on therapy, lapatinib should be discontinued and patients should not be retreated.

Major

estradiol Migraine

Applies to: Migraine

The use of estrogens is considered by manufacturers and some authorities to be contraindicated in patients with active thrombotic, thromboembolic, or thrombophilic disorders. The use of estrogen-containing oral contraceptives is additionally deemed contraindicated in patients with a history of such disorders and/or current cerebrovascular or coronary artery disease. Females with a history of migraines with aura are at an increased risk for stroke and this stroke risk may be further increased in females who have migraines with aura with use of combination oral contraceptives. Hypercoagulability and changes in various clotting factors and blood components have been observed in women receiving estrogen therapy. Known preexisting risk factors for increased thromboembolic or cardiovascular events include smoking, especially over age of 35; hypertension; hyperlipidemia; obesity; diabetes; age over 40; and lupus. Therapy with estrogens should be administered cautiously in the lowest effective dosage and only after careful consideration of risks and benefits. Estrogens should be avoided in patients with a history of thrombotic and thromboembolic disorders associated with estrogen use, except when used in the treatment of metastatic breast or prostatic malignancy.

Major

estradiol Neoplasia -- Estrogen Dependent

Applies to: Neoplasia -- Estrogen Dependent

The use of estrogens is generally contraindicated in patients with known or suspected estrogen-dependent neoplasia such as breast and endometrial cancer, since it may stimulate tumor proliferation. High dosages of estrogens may be used for the palliative treatment of inoperable, metastatic breast cancer, but only in appropriately selected men and postmenopausal women.

Major

lapatinib Pulmonary Impairment

Applies to: Pulmonary Impairment

Pulmonary toxicity, sometimes fatal has been reported with agents that block HER2 activity. Pulmonary toxicity includes dyspnea, interstitial pneumonitis, pulmonary infiltrates, pleural effusions, non-cardiogenic pulmonary edema, pulmonary insufficiency and hypoxia, acute respiratory distress syndrome, and pulmonary fibrosis. Patients with symptomatic intrinsic lung disease or with extensive tumor involvement of the lungs, resulting in dyspnea at rest may be at increased risk of pulmonary toxicity and appear to have more severe toxicity. Patients should be monitored for pulmonary symptoms. Permanently discontinue treatment with these agents in patients diagnosed with interstitial lung disease or pneumonitis and institute appropriate care.

Major

lapatinib Pulmonary Impairment

Applies to: Pulmonary Impairment

The use of certain EGFR inhibitors has been associated with pulmonary toxicity. Serious cases of interstitial lung disease (ILD), including fatal cases and interstitial pneumonitis or pulmonary fibrosis have been reported. Caution is recommended when using these agents in patients with a history of interstitial pneumonitis or pulmonary fibrosis or those patients presenting with acute onset of new or progressive unexplained pulmonary symptoms such as dyspnea, cough, and fever pending diagnostic evaluation. If ILD is confirmed, permanently discontinue these agents and institute appropriate measures.

Major

estradiol Thrombotic/Thromboembolic Disorder

Applies to: Thrombotic / Thromboembolic Disorder

The use of estrogens is considered by manufacturers and some authorities to be contraindicated in patients with active thrombotic, thromboembolic, or thrombophilic disorders. The use of estrogen-containing oral contraceptives is additionally deemed contraindicated in patients with a history of such disorders and/or current cerebrovascular or coronary artery disease. Females with a history of migraines with aura are at an increased risk for stroke and this stroke risk may be further increased in females who have migraines with aura with use of combination oral contraceptives. Hypercoagulability and changes in various clotting factors and blood components have been observed in women receiving estrogen therapy. Known preexisting risk factors for increased thromboembolic or cardiovascular events include smoking, especially over age of 35; hypertension; hyperlipidemia; obesity; diabetes; age over 40; and lupus. Therapy with estrogens should be administered cautiously in the lowest effective dosage and only after careful consideration of risks and benefits. Estrogens should be avoided in patients with a history of thrombotic and thromboembolic disorders associated with estrogen use, except when used in the treatment of metastatic breast or prostatic malignancy.

Major

lapatinib Ventricular Arrhythmia

Applies to: Ventricular Arrhythmia

Cardiomyopathy was observed in clinical trials of certain EGFR inhibitors. Assess Left Ventricular Ejection Fraction (LVEF) by echocardiogram or multigated acquisition (MUGA) scan before initiation of these agents and then at 3 month intervals while on treatment. Caution is recommended when prescribing these agents to patients with conditions that could impair left ventricular function and it is recommended to withhold treatment with these agents if ejection fraction drops below the established lower limit of normal. For symptomatic congestive heart failure or persistent, asymptomatic LV dysfunction that does not resolve within 4 weeks, permanently discontinue these agents.

Moderate

estradiol Angioedema

Applies to: Angioedema

The use of exogenous estrogens may induce or exacerbate symptoms of angioedema, particularly in women with hereditary angioedema. Close monitoring is recommended when prescribing these agents to patients predisposed to angioedema.

Moderate

lapatinib Arrhythmias

Applies to: Arrhythmias

Decreases in left ventricular ejection fraction (LVEF) have been reported with agents that block HER2 activity. Patients who have received prior anthracyclines, those who received anthracycline after stopping therapy with agents that block HER2 activity, or patients who received prior radiotherapy to the chest area may be at higher risk of decreased LVEF. Therapy with these agents should be administered cautiously in patients with a previous history of heart conditions. Evaluate cardiac function before, during, and upon completion of treatment. Withhold or discontinue therapy with agents that block HER2 activity as appropriate, and for a confirmed clinically significant decrease in left ventricular function, or if the LVEF has not improved or has declined further. It is recommended to monitor overall cardiac function and LVEF by echocardiogram or MUGA scan as appropriate.

Moderate

estradiol Asthma

Applies to: Asthma

Estrogens and progestogens may cause fluid retention, particularly when given in high dosages or for prolonged periods. Therapy with these agents should be administered cautiously in patients who have preexisting problems with excess fluid. In addition, patients with conditions that may be adversely affected by fluid accumulation, such as asthma, epilepsy, migraine, and cardiovascular or renal dysfunction, should be observed for exacerbation of their condition during estrogen and/or progestogen therapy.

Moderate

estradiol Congestive Heart Failure

Applies to: Congestive Heart Failure

Estrogens and progestogens may cause fluid retention, particularly when given in high dosages or for prolonged periods. Therapy with these agents should be administered cautiously in patients who have preexisting problems with excess fluid. In addition, patients with conditions that may be adversely affected by fluid accumulation, such as asthma, epilepsy, migraine, and cardiovascular or renal dysfunction, should be observed for exacerbation of their condition during estrogen and/or progestogen therapy.

Moderate

lapatinib Congestive Heart Failure

Applies to: Congestive Heart Failure

Decreases in left ventricular ejection fraction (LVEF) have been reported with agents that block HER2 activity. Patients who have received prior anthracyclines, those who received anthracycline after stopping therapy with agents that block HER2 activity, or patients who received prior radiotherapy to the chest area may be at higher risk of decreased LVEF. Therapy with these agents should be administered cautiously in patients with a previous history of heart conditions. Evaluate cardiac function before, during, and upon completion of treatment. Withhold or discontinue therapy with agents that block HER2 activity as appropriate, and for a confirmed clinically significant decrease in left ventricular function, or if the LVEF has not improved or has declined further. It is recommended to monitor overall cardiac function and LVEF by echocardiogram or MUGA scan as appropriate.

Moderate

estradiol Diabetes Mellitus

Applies to: Diabetes Mellitus

Impaired glucose tolerance has been observed in some patients administered oral contraceptives and appears to be related primarily to the estrogen dose. However, progestogens can increase insulin secretion and produce insulin resistance to varying degrees, depending on the agent. Caution and close monitoring are recommended in patients with diabetes mellitus during therapy with estrogens and/or progestogens, and adjustments made accordingly in their antidiabetic regimen.

Moderate

estradiol Fluid Retention

Applies to: Fluid Retention

Estrogens and progestogens may cause fluid retention, particularly when given in high dosages or for prolonged periods. Therapy with these agents should be administered cautiously in patients who have preexisting problems with excess fluid. In addition, patients with conditions that may be adversely affected by fluid accumulation, such as asthma, epilepsy, migraine, and cardiovascular or renal dysfunction, should be observed for exacerbation of their condition during estrogen and/or progestogen therapy.

Moderate

estradiol Gallbladder Disease

Applies to: Gallbladder Disease

A two- to four-fold increase in risk of gallbladder disease has been noted in women receiving postmenopausal estrogen therapy. The risk for gallbladder disease may be less for premenopausal women using oral contraceptives containing low-dose estrogens and/or progestins. Therapy with estrogens should be administered cautiously in patients with preexisting gallbladder disease or a history of pregnancy-related cholestasis.

Moderate

lapatinib History - Myocardial Infarction

Applies to: History - Myocardial Infarction

Decreases in left ventricular ejection fraction (LVEF) have been reported with agents that block HER2 activity. Patients who have received prior anthracyclines, those who received anthracycline after stopping therapy with agents that block HER2 activity, or patients who received prior radiotherapy to the chest area may be at higher risk of decreased LVEF. Therapy with these agents should be administered cautiously in patients with a previous history of heart conditions. Evaluate cardiac function before, during, and upon completion of treatment. Withhold or discontinue therapy with agents that block HER2 activity as appropriate, and for a confirmed clinically significant decrease in left ventricular function, or if the LVEF has not improved or has declined further. It is recommended to monitor overall cardiac function and LVEF by echocardiogram or MUGA scan as appropriate.

Moderate

estradiol Hyperlipidemia

Applies to: Hyperlipidemia

Estrogens may cause adverse lipid changes. Use of estrogens has been associated with elevations in triglyceride levels, particularly in women with pre-existing hypertriglyceridemia. Discontinue therapy if elevated triglycerides lead to pancreatitis. Manage hypercholesterolemia appropriately as indicated.

Moderate

lapatinib Hypertension

Applies to: Hypertension

Decreases in left ventricular ejection fraction (LVEF) have been reported with agents that block HER2 activity. Patients who have received prior anthracyclines, those who received anthracycline after stopping therapy with agents that block HER2 activity, or patients who received prior radiotherapy to the chest area may be at higher risk of decreased LVEF. Therapy with these agents should be administered cautiously in patients with a previous history of heart conditions. Evaluate cardiac function before, during, and upon completion of treatment. Withhold or discontinue therapy with agents that block HER2 activity as appropriate, and for a confirmed clinically significant decrease in left ventricular function, or if the LVEF has not improved or has declined further. It is recommended to monitor overall cardiac function and LVEF by echocardiogram or MUGA scan as appropriate.

Moderate

estradiol Hypoparathyroidism

Applies to: Hypoparathyroidism

Estrogens should be used with caution in individuals with severe hypocalcemia or hypoparathyroidism. Estrogen-induced hypocalcemia may occur in patients with hypoparathyroidism; consider whether the benefits of estrogen therapy outweigh the risks.

Moderate

estradiol Liver Disease

Applies to: Liver Disease

Estrogens are primarily metabolized by the liver. Use of estrogen therapy is contraindicated in patients with liver dysfunction or disease. Patients with impaired hepatic function may be at increased risk for adverse effects associated with estrogen administration due to decreased drug clearance. Patients with hepatic hemangiomas are at increased risk of exacerbation with use of estrogens. Therapy with estrogens should be administered cautiously in patients with cholestatic jaundice associated with past estrogen use or with pregnancy. In addition, clinicians should be aware that estrogen therapy may affect liver function tests.

Moderate

estradiol Migraine

Applies to: Migraine

Estrogens and progestogens may cause fluid retention, particularly when given in high dosages or for prolonged periods. Therapy with these agents should be administered cautiously in patients who have preexisting problems with excess fluid. In addition, patients with conditions that may be adversely affected by fluid accumulation, such as asthma, epilepsy, migraine, and cardiovascular or renal dysfunction, should be observed for exacerbation of their condition during estrogen and/or progestogen therapy.

Moderate

lapatinib Myocardial Infarction

Applies to: Myocardial Infarction

Decreases in left ventricular ejection fraction (LVEF) have been reported with agents that block HER2 activity. Patients who have received prior anthracyclines, those who received anthracycline after stopping therapy with agents that block HER2 activity, or patients who received prior radiotherapy to the chest area may be at higher risk of decreased LVEF. Therapy with these agents should be administered cautiously in patients with a previous history of heart conditions. Evaluate cardiac function before, during, and upon completion of treatment. Withhold or discontinue therapy with agents that block HER2 activity as appropriate, and for a confirmed clinically significant decrease in left ventricular function, or if the LVEF has not improved or has declined further. It is recommended to monitor overall cardiac function and LVEF by echocardiogram or MUGA scan as appropriate.

Moderate

lapatinib Post MI Syndrome

Applies to: Post MI Syndrome

Decreases in left ventricular ejection fraction (LVEF) have been reported with agents that block HER2 activity. Patients who have received prior anthracyclines, those who received anthracycline after stopping therapy with agents that block HER2 activity, or patients who received prior radiotherapy to the chest area may be at higher risk of decreased LVEF. Therapy with these agents should be administered cautiously in patients with a previous history of heart conditions. Evaluate cardiac function before, during, and upon completion of treatment. Withhold or discontinue therapy with agents that block HER2 activity as appropriate, and for a confirmed clinically significant decrease in left ventricular function, or if the LVEF has not improved or has declined further. It is recommended to monitor overall cardiac function and LVEF by echocardiogram or MUGA scan as appropriate.

Moderate

estradiol Renal Dysfunction

Applies to: Renal Dysfunction

Estrogens and progestogens may cause fluid retention, particularly when given in high dosages or for prolonged periods. Therapy with these agents should be administered cautiously in patients who have preexisting problems with excess fluid. In addition, patients with conditions that may be adversely affected by fluid accumulation, such as asthma, epilepsy, migraine, and cardiovascular or renal dysfunction, should be observed for exacerbation of their condition during estrogen and/or progestogen therapy.

Moderate

lapatinib Renal Dysfunction

Applies to: Renal Dysfunction

Lapatinib pharmacokinetics have not been specifically studied in patients with renal impairment or in patients undergoing hemodialysis. Close monitoring is recommended.

Moderate

estradiol Seizures

Applies to: Seizures

Estrogens and progestogens may cause fluid retention, particularly when given in high dosages or for prolonged periods. Therapy with these agents should be administered cautiously in patients who have preexisting problems with excess fluid. In addition, patients with conditions that may be adversely affected by fluid accumulation, such as asthma, epilepsy, migraine, and cardiovascular or renal dysfunction, should be observed for exacerbation of their condition during estrogen and/or progestogen therapy.

Moderate

lapatinib Thrombocytopenia

Applies to: Thrombocytopenia

Thrombocytopenia has been reported with the use of agents that block HER2 activity. Monitor platelet counts prior to initiation of therapy and prior to each dose. If appropriate modify the dose according to clinical guidelines. Patients with decreased platelet count and patients on anti-coagulant treatment should be closely monitored during treatment with these agents.

Moderate

estradiol Thyroid Disease

Applies to: Thyroid Disease

When administering estrogen and/or progestogen therapy in patients with thyroid disorders, clinicians should be aware that these hormones may affect thyroid function tests. Changes have mostly been reported with the use of combination oral contraceptives. Specifically, thyroid-binding globulin (TBG) may be increased, resulting in elevated circulating total thyroid hormone, as measured by PBI (protein-bound iodine), T4 by column or radioimmunoassay, or T3 by radioimmunoassay. Free T3 resin uptake may be decreased. On the contrary, a decrease in TBG and, consequently, thyroxine concentration, has been reported by the manufacturers of the progestin-only (norethindrone) oral contraceptives. Patients on thyroid replacement therapy may require higher doses of thyroid hormone and appropriate monitoring.

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.


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.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.