Can Orgovix (dienogest) cause hypothyroidism?

Orgovyx Does Not Cause Hypothyroidism

Orgovyx (relugolix) does not cause hypothyroidism. The question appears to confuse Orgovyx (relugolix), which is a GnRH antagonist used for advanced prostate cancer, with dienogest, which is a different medication entirely.

Clarification of Medications

Orgovyx (Relugolix)

• Orgovyx is the brand name for relugolix, a GnRH antagonist approved for the treatment of advanced prostate cancer
• According to the AUA guidelines, there is no mention of hypothyroidism as a side effect of Orgovyx 1
• The common side effects of Orgovyx (relugolix) include fatigue, hypertension, diarrhea, and hot flashes

Apalutamide and Enzalutamide

• The AUA guidelines specifically mention hypothyroidism as an adverse effect of apalutamide (Erleada), not Orgovyx 1
• In the SPARTAN trial, hypothyroidism occurred in 8.1% of patients taking apalutamide versus 2.0% in the placebo group 1
• These events were generally identified early after starting treatment and were manageable with medical therapy 1

Medications That Can Cause Hypothyroidism

Several medications are known to cause hypothyroidism:

1. Immune checkpoint inhibitors: Can cause thyroid dysfunction in 6-20% of patients 1
2. Apalutamide: As mentioned above, causes hypothyroidism in approximately 8% of patients 1
3. Amiodarone and lithium: Common causes of drug-induced hypothyroidism 2
4. Dienogest: Some studies have shown that dienogest (when combined with ethinyl estradiol) can affect thyroid hormone binding proteins but not cause clinical hypothyroidism 3

Monitoring Recommendations

For patients taking medications that can cause hypothyroidism:

• Baseline thyroid function tests (TSH and free T4) should be obtained before starting treatment 1
• Regular monitoring of thyroid function during treatment is recommended 1
• For apalutamide specifically, particular attention should be paid to monitoring TSH in individuals with known hypothyroidism 1

Management of Drug-Induced Hypothyroidism

If hypothyroidism develops:

• Levothyroxine replacement therapy is the standard treatment 2
• The American Thyroid Association recommends maintaining TSH within the reference range (0.45-4.5 mIU/L) 4
• Monitoring TSH levels every 6-8 weeks during dose titration is recommended 4

Conclusion

The question appears to be based on a misunderstanding about Orgovyx (relugolix). Orgovyx is not associated with hypothyroidism according to available evidence. However, other medications used in prostate cancer treatment, such as apalutamide, do have documented effects on thyroid function that require monitoring.