Ullipristal, as an emergency contraceptive can be taken upto how many hours of unprotected intercourse
The core concept here is the timing of administration for emergency contraception. The question is asking up to how many hours after unprotected intercourse Ullipristal can be taken. I remember that different EC methods have different time windows. Levonorgestrel is effective up to 72 hours, but Ullipristal has a longer window. I think it's 120 hours, which is 5 days. Let me confirm that. Yes, Ullipristal is approved for use up to 120 hours post-intercourse, making it effective longer than the standard 3-day methods.
Now, the correct answer is 120 hours. So why is that? Because Ullipristal's mechanism allows it to delay ovulation even if it occurs after taking the pill. It binds to progesterone receptors in the endometrium and corpus luteum, preventing the necessary changes for implantation and maintaining the corpus luteum. This action can be effective even if ovulation hasn't occurred yet, hence the longer window.
For the wrong options: Let's say the options are A: 24, B: 48, C: 72, D: 120. The correct answer is D. The other options are for different EC methods. Levonorgestrel is 72 hours (72 hours is 3 days), so Option C (72) would be a trap for someone confusing the two. Options A and B are shorter and not standard for EC. Also, copper IUD is another method effective up to 5 days but isn't the drug in question here.
The clinical pearl here is to remember that Ullipristal is the EC with the longest window (5 days) and that it's a SPRM, not a progestin. Students often mix up the time frames for different EC methods. Emphasizing that Ullipristal is 120 hours (5 days) is key. Also, note that it's a single-dose pill, which is more user-friendly than some other methods.
I need to structure this into the required sections, making sure each part is concise and fits within the character limit. Use bold for section headers and key terms. Check that each wrong option is addressed clearly, explaining why they're incorrect. Make sure the clinical pearl is a high-yield fact that the student should remember for exams.
**Core Concept**
Ullipristal is a selective progesterone receptor modulator (SPRM) used as an emergency contraceptive. It works by delaying or inhibiting ovulation, with efficacy dependent on the timing of administration relative to ovulation.
**Why the Correct Answer is Right**
Ullipristal acts by binding to progesterone receptors in the endometrium and corpus luteum, blocking progesterone-mediated processes essential for implantation. Its pharmacokinetics