Do omeprazole and famotidine (H2 receptor antagonist) affect hormone replacement therapy (HRT)?

From the Guidelines

Omeprazole and famotidine generally do not significantly affect hormone replacement therapy (HRT). These acid-reducing medications work through different mechanisms than HRT and don't typically interfere with the absorption or metabolism of estrogen, progesterone, or testosterone used in hormone therapy. Omeprazole (a proton pump inhibitor) and famotidine (an H2 blocker) primarily affect stomach acid production, while HRT medications are processed through different metabolic pathways in the liver. However, individual responses can vary, and some patients might experience subtle changes in hormone levels when taking these medications together. If you're on HRT and need to start acid-reducing medication, you can generally take them as prescribed without adjusting your hormone dosage. That said, it's always advisable to inform your healthcare provider about all medications you're taking, as they can monitor for any unexpected interactions or changes in hormone levels through routine blood work. If you notice any changes in your HRT effectiveness after starting these acid reducers, consult your healthcare provider for personalized guidance.

Key Points to Consider

• The primary mechanism of action of omeprazole and famotidine does not directly interfere with HRT medications 1.
• HRT is used for various purposes, including the management of menopausal symptoms and the prevention of chronic conditions, but its use should be individualized based on a woman's risk factors and preferences 1.
• While there is no direct evidence that omeprazole and famotidine affect HRT, monitoring for any changes in hormone levels or symptoms is recommended when starting these medications together.
• The decision to initiate or continue HRT should be made after discussing the benefits and risks with a healthcare provider, considering the latest guidelines and evidence available 1.

Recommendations for Clinical Practice

• Inform your healthcare provider about all medications you're taking, including omeprazole and famotidine, if you're on HRT.
• Monitor for any changes in HRT effectiveness or hormone levels when starting acid-reducing medications.
• Follow the recommended dosage and duration of HRT as advised by your healthcare provider, and attend regular follow-up appointments to assess the need for continued therapy.

From the FDA Drug Label

Omeprazole, given in oral doses of 30 or 40 mg for 2 to 4 weeks, had no effect on thyroid function, carbohydrate metabolism, or circulating levels of parathyroid hormone, cortisol, estradiol, testosterone, prolactin, cholecystokinin or secretin.

The FDA drug label does not provide direct information on the effect of omeprazole and famotidine on hormone replacement therapy (HRT). However, it does mention that omeprazole had no effect on circulating levels of estradiol and testosterone, which are hormones that may be relevant to HRT.

• Key points:
  • No direct effect on HRT is mentioned.
  • No effect on estradiol and testosterone levels.
  • Famotidine is not mentioned in the provided drug label. 2

From the Research

Effect of Omeprazole and Famotidine on Hormone Replacement Therapy (HRT)

• There is no direct evidence in the provided studies that omeprazole and famotidine (H2 receptor antagonist) affect hormone replacement therapy (HRT) 3, 4, 5, 6.
• However, a study on the effects of omeprazole on endocrine function in man found that omeprazole did not interfere with various endocrine functions, including follicle-stimulating hormone (FSH), luteinising hormone (LH), prolactin, testosterone, thyroid-stimulating hormone (TSH), and serum thyroxine (T4) and tri-iodothyronine (T3) levels 7.
• The studies on HRT focused on the effects of different HRT regimens on plasma sex hormone-binding globulin, androgen, and insulin-like growth factor-1 levels in postmenopausal women 3, 4, 5, 6.
• None of the studies investigated the specific interaction between omeprazole, famotidine, and HRT, suggesting that there is limited research on this topic 3, 4, 5, 6, 7.

Hormone Replacement Therapy (HRT) Regimens

• Different HRT regimens, including oral and transdermal estrogen, were found to have varying effects on plasma hormone levels in postmenopausal women 3, 4, 5.
• Oral HRT was associated with increased plasma sex hormone-binding globulin (SHBG) levels, while transdermal HRT had no significant effect on SHBG levels 4.
• The efficacy of estriol for estrogen replacement therapy was found to be correlated with the degree of decrease in plasma FSH and LH levels 5.

Endocrine Function and Omeprazole

• Omeprazole was found to have no significant effect on various endocrine functions, including basal and stimulated hormone levels, in healthy subjects 7.
• The study suggested that omeprazole is unlikely to cause significant interference in endocrine function in clinical practice 7.