Relugolix is an oral gonadotropin-releasing hormone (GnRH) receptor antagonist, often formulated as a fixed-dose combination with estrogens (e.g., estradiol) and progestogens (e.g., norethindrone acetate). It is used to treat heavy menstrual bleeding associated with uterine fibroids and moderate-to-severe pain associated with endometriosis.

Dosage and Administration of Relugolix

Pre-Treatment Preparation

Pregnancy Exclusion: Confirming that the patient is not pregnant is a prerequisite for treatment with this medication.

Discontinuation of Hormonal Contraceptives: To avoid drug interactions and increased potential risks, all hormonal contraceptive methods must be stopped before starting the medication.

Recommended Dosage and Administration Method

Loading Dose on Day 1: 360mg, taken orally. Maintenance Dose: 120mg, taken orally once daily at a fixed time.

Administration Time: It is recommended to take the medication at approximately the same time each day, either with food or on an empty stomach, to improve adherence.

Initiation Timing: The medication should be started as soon as possible after the onset of menstruation, and no later than the 7th day of menstruation. Starting the medication later than this timing may lead to initial irregular or heavy bleeding.

Management of Missed Doses

If a missed dose is remembered on the same day, take it as soon as possible.

On the next day, resume taking the medication at the normal scheduled time; do not take a double dose.

Avoid taking two tablets at the same time to make up for a missed dose, as this may increase the risk of adverse reactions.

Dosage Adjustment of Relugolix

Adjustment for Concomitant Use with P-gp Inhibitors

Relugolix is a substrate of P-glycoprotein (P-gp). When used concomitantly with oral P-gp inhibitors (e.g., certain antibiotics, cardiovascular drugs), its plasma concentration may increase, raising the risk of adverse reactions.

Recommended Practice: Concomitant use should be avoided as much as possible.

If Concomitant Use is Unavoidable: Take the Relugolix combination product first.

Take the P-gp inhibitor at least 6 hours later.

Closely monitor for the occurrence of adverse reactions.

Concomitant Use with P-gp and Strong CYP3A Inducers

Concomitant use with P-gp combined strong CYP3A inducers (e.g., rifampicin) significantly reduces the plasma concentrations of Relugolix, estradiol, and norethindrone, impairing therapeutic efficacy.

Recommendation: Concomitant use should be avoided entirely.

Medication for Special Populations of Relugolix

Patients with Hepatic Impairment

Contraindicated: Use is strictly prohibited in patients with known liver injury or liver disease.

Reason: Hormonal medications require hepatic metabolism; hepatic insufficiency can increase drug exposure.

During Treatment: If symptoms of liver injury (such as jaundice, right upper abdominal pain) occur, seek medical attention immediately and consider discontinuing the medication.

Patients with Renal Impairment

Patients with mild-to-severe renal impairment (creatinine clearance ≥15mL/min) do not require dosage adjustment.

However, data on the use of this medication in patients with severe renal impairment or those requiring dialysis are insufficient, and careful evaluation is needed before use.

Pregnant and Lactating Women

Pregnant Women: Contraindicated. This medication may cause early pregnancy loss; pregnancy must be excluded before starting treatment, and if pregnancy is confirmed during treatment, the medication should be discontinued immediately.

Lactating Women: Relugolix and hormonal components can be excreted in breast milk, which may affect milk production and infant development.

Breastfeeding is not recommended during treatment, and the necessity of treatment and potential risks should be comprehensively evaluated.

Women of Reproductive Potential

During treatment and within 1 week after discontinuing the medication, effective non-hormonal contraceptive methods (e.g., condoms, spermicides) must be used.

Avoid using hormonal contraceptives, as they may increase estrogen-related adverse reactions and reduce the efficacy of Relugolix.