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Antiprogestogen

Mifepristone

Brand names: Mifegyne

A progesterone receptor antagonist used, in combination with a prostaglandin, for medical termination of pregnancy and for the management of miscarriage.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

Clinical monograph

How it works

It blocks progesterone receptors, sensitising the myometrium to prostaglandins, softening and dilating the cervix, and promoting decidual breakdown.

Prescribing in practice

  • It is used as part of a regimen with a prostaglandin such as misoprostol and must be provided within an appropriate clinical and legal framework with arrangements for managing bleeding and incomplete procedure.
  • Confirm gestation and exclude ectopic pregnancy before use, as it is not a treatment for ectopic pregnancy.
  • Avoid in suspected ectopic pregnancy, chronic adrenal failure, and known hypersensitivity, and use with caution where there is an in-situ intrauterine device or relevant comorbidity.

Monitoring

Monitor for heavy bleeding, pain and completeness of the process, with follow-up to confirm the pregnancy has fully passed.

Counselling the patient

  • Bleeding and cramping are expected after the prostaglandin is taken.
  • Seek urgent care for very heavy bleeding, severe pain, fever, or feeling faint.
  • Attend the follow-up review to confirm the process is complete.

Evidence & guidelines

NICE guidance on abortion care (NG140) supports combined mifepristone and misoprostol regimens for medical termination of pregnancy.

Reference: RCOG TOP Guidelines 2019; Faculty of Sexual and Reproductive Healthcare (FSRH); Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).