Relugolix
Relugolix is an oral, non-peptide GnRH antagonist for advanced prostate cancer (Orgovyx) and, with add-back hormones, for uterine fibroids and endometriosis (Myfembree/Ryeqo). It suppresses sex steroids rapidly and without flare, with fast recovery after stopping.
01 Overview
Relugolix is a small-molecule GnRH receptor antagonist taken once daily by mouth. In prostate cancer it achieves castrate testosterone faster than leuprolide and, in trials, with fewer major cardiovascular events, while allowing quicker testosterone recovery after discontinuation.
Combined with estradiol and norethindrone, it treats fibroid-related heavy bleeding and endometriosis pain, with the add-back limiting hypoestrogenic side effects.
02 Mechanism
Oral non-peptide antagonism of the pituitary GnRH receptor rapidly and reversibly suppresses LH/FSH and downstream sex steroids without an agonist flare.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Prostate cancer maintenance | 120 mg/day | Oral | 120 mg once daily thereafter |
| Prostate cancer loading | 360 mg | Oral | 360 mg loading dose on day 1 |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Rapid castrate testosteroneFaster testosterone suppression than leuprolide, without a flare. | castrate by ~day 4 | Clinical | |
| Faster testosterone recoveryTestosterone recovers more quickly after stopping than with depot agonists, useful for intermittent therapy. | Clinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Hot flushesVasomotor flushing is the most frequent adverse effect. | Moderate | Very common | Clinical | |
| Diarrhea and GI upsetLoose stools and abdominal discomfort reported in prostate-cancer trials. | Mild | Common | Clinical |