Dr. Chapa’s Clinical Pearls — Episode Summary

Episode Title:

Extended Release Nifedipine Intrapartum For Severe HTN
Date: October 14, 2025
Host: Dr. Chapa

Episode Overview

This episode addresses a nuanced clinical question: Is there evidence and support for using extended release (ER) nifedipine during labor (intrapartum) to manage severe hypertension in preeclampsia? Dr. Chapa breaks down the data, evidence quality, existing guidelines, and practical considerations, responding to a listener's query inspired by the Society of Academic Specialists in General Obstetrics and Gynecology's (SASGOG) "Pearls of Excellence." The episode aims to clarify when and how ER nifedipine can be used, reviewing recent trials and distinguishing between guideline-sanctioned urgent therapy and maintenance approaches for blood pressure control.

Key Discussion Points & Insights

1. Media Portrayal of OB Emergencies & Real-Life Relevance

• Dr. Chapa recounts a scene from Grey's Anatomy depicting preeclampsia with hepatic injury, expressing relief when TV brings attention to obstetric emergencies but cautioning about medical inaccuracies.

  • Quote:
    "I always cringe a little bit...when I see some OB issue portrayed in a movie or television show. On the one hand, I'm so thankful that attention is being given...but...shows do things that are completely off." (03:00)

• Uses this as a segue to highlight the clinical importance and topicality of preeclampsia management.

2. Listener’s Clinical Question

• A podcast listener asks about a statement found in "Pearls of Excellence" that endorsed ER nifedipine as an adjunct or maintenance therapy for severe hypertension intrapartum after acute IV therapy.
  • The clinical challenge: Is ER nifedipine evidence-based and practically supported for this use?

3. Guideline Foundation: Standards of Care

• ACOG and SOGC Recommendations:
  • First-line, urgent management of severe hypertension (≥160/110 mmHg) in pregnancy uses:
    • IV hydralazine
    • IV labetalol
    • Immediate release oral nifedipine
      (see Practice Bulletin 222 and Committee Opinion 692)
  • Maintenance therapy or prophylaxis is not detailed in these guidelines.
  • Quote:
    "The gold standard, the first line, the typical, is IV hydralazine, IV Labetalol or PO Nifedipine. Those are the standards." (09:40)
  • Urgent therapy is about rapid BP control; maintenance therapy focuses on preventing recurrent severe hypertension.

4. Pearls of Excellence & Extended Use

• The 2018 SASGOG "Pearls of Excellence" summary highlights that, following acute IV antihypertensive therapy, it is "often prudent to initiate oral labetalol or extended release nifedipine to maintain blood pressure below the severe range" (08:10).

  • Quotes:
    "It is often prudent to initiate oral labetalol or extended release nifedipine to maintain blood pressure below the severe range." (09:00) "Notice those words. Maintain...you are initiating action to keep blood pressure down rather than reaction by waiting for her to become hypertensive in the severe range." (09:50)
  • Context: These are academic society recommendations, not universal standards.

• Clinical application:

  • ER nifedipine or oral labetalol can be given to maintain or prevent rebound severe hypertension, typical dosages:
    • Oral labetalol: 200 mg, BID or TID
    • ER nifedipine: 30 mg once daily
  • Decision to start after how many episodes of urgent therapy can be clinician-dependent.
    • "If we give...two or more IV doses, it's something that we have done. It's not our standard protocol, but we have considered..." (12:05)

5. Recent Evidence: The Ohio State Trial (2022/2023)

• Trial Summary:

  • Triple-blind, placebo-controlled
  • Pregnant women with preeclampsia/severe features undergoing induction (22–42 weeks)
    • Randomized: ER nifedipine 30mg daily vs. placebo
  • Primary outcome: Need for >1 dose of acute therapy for BP ≥160/110 for >10 min

• Results:

  • Needing acute therapy: 34% (nifedipine) vs. 55% (placebo)
  • Relative risk: 0.62; ~40% reduction in need for urgent therapy
  • Number needed to treat: 5
  • Fewer cesarean deliveries (not statistically robust)
  • NICU admission lower in nifedipine group
  • No increase in adverse neonatal outcomes

• Quote:
  "Initiation of extended release nifedipine is effective in reducing intrapartum acute hypertensive therapy among women with preeclampsia with severe features." (25:25)

  • Dr. Chapa: "It does make sense...it is helpful. Now if you do give the oral extended release nifedipine...probably don't give a 10 milligram of oral immediate release...for the acute." (26:20)

• Cautions:

  • This is single, well-conducted trial.
    • "The not so good news is that's kind of it. But it was enough to make it into the 2018 Society... Now remember I said that was 2018. This publication came out later because they updated..." (28:10)
  • Still not established as first-line by major guidelines.

6. Practical Pearls & Clinical Discretion

• When to use ER nifedipine?

  • Not after a single episode of severe hypertension
  • Consider if two or more rounds of acute antihypertensive therapy are required
  • Ensure patient can tolerate oral medication (no vomiting, delayed gastric emptying, etc.)
  • Avoid stacking (if using ER nifedipine for maintenance, opt for different IV agent for acute rescue, and vice versa)
    • "If I give a patient a medication, a 200mg oral labetalol intrapartum, I'm probably not going to chase her with IV labetalol because I don't want it to have a stacking effect." (27:10)

• Selection considerations:

  • Use “rule of 55”: difference between systolic and diastolic guides agent choice
    • Delta >55: consider beta blocker
    • Delta <55: peripheral vasodilator like nifedipine
  • Quote:
    "Tailor it to what's happening in the patient's profile. Okay? If you haven't heard of the rule of 55...you can go back and search for it." (14:28)

• Policy & Protocols:

  • Use in accordance with institutional policy; if none exists, get approval/documentation
  • Not explicitly covered in ACOG Practice Bulletin 222 or Committee Opinion 692 (29:30)

Notable Quotes & Memorable Moments

• On episode inspiration:
  “We get ideas for the show not just from real world encounters, but from questions that come in through our social media channels.” (04:20)
• Pearls of Excellence on ER nifedipine:
  “Once IV acute treatment is given, it is often prudent to initiate oral labetalol or extended release nifedipine to … maintain blood pressure below the severe range.” (10:50)
• On evidence quality:
  “Is there data? Absolutely. Is there a lot of data? Nope. Nope.” (05:50)
• Evidence-based yet not first line:
  “Can you do extended release after the patient has received IV urgent hypertension? Of course. Is it standard therapy now? No, it is not.” (06:30)
• Take-home summary:
  “So is it reasonable to do that? Absolutely. Is there data? Yes, but we definitely need more. And unfortunately, the first line treatment is one that I don't like, which is just chasing her with a PRN medication.” (28:40)

Key Timestamps

| Timestamp | Segment / Topic | |------------|--------------------------------------------------------------------------------------------------| | 03:00 | Dr. Chapa discusses medical media depictions, segues to real-life preeclampsia | | 04:20 | Introducing the listener’s question about ER nifedipine | | 08:06 | Direct quote from SASGOG’s “Pearls of Excellence” | | 09:40 | Gold standard/urgent therapy in ACOG guidelines clarified | | 12:05 | When Dr. Chapa’s team considers ER nifedipine or oral labetalol for maintenance | | 14:28 | The “rule of 55” and agent selection explained | | 22:36 | ER nifedipine trial introduction, methodology explained | | 24:53 | Trial results: efficacy and safety outcomes summarized | | 26:20 | Importance of not stacking agents, practical best-practices | | 28:10 | Single-study evidence caveat and Pearls of Excellence timeline | | 29:30 | Emphasis on policy adherence and practical summary |

Practical Summary / Clinical Pearl

Extended release nifedipine can be reasonably considered as an adjunct to maintain blood pressure below severe range in intrapartum patients with preeclampsia who require multiple urgent antihypertensive treatments. While not a first-line or guideline-sanctioned standard, a well-conducted RCT supports its safety and efficacy for this use. Selection between ER nifedipine and oral labetalol (and their timing) should be individualized, guided by patient characteristics and institutional protocols.

Final Clinical Pearl:
“Is there data for extended released nifedipine intrapartum? Yes...Not a problem to do either, although it is not mentioned in ACOG's original guidance on this…which uses either IV or immediate acting for faster and tighter control.” (29:35)

This episode provided a focused, evidence-based, and pragmatic exploration of managing intrapartum hypertension in preeclampsia, clarifying the place of extended release nifedipine as a maintenance (not acute) therapy in select cases.