Wondering how to use Mifeprex? This guide explains how to take Mifeprex pills, including the correct dosage and what to expect. Learn how to take Mifeprex safely and effectively for a medical abortion. Many ask how long it takes for Mifeprex to take effect. It typically begins working within hours, but full effects may take up to 24-48 hours. Understanding the process ensures a safe experience. Read on for a step-by-step guide on Mifeprex usage and important precautions.