Nifedipine MR

• HTN in pregnancy when Labetalol contraindicated
• Second-line, mild-to-moderate HTN/pre-eclampsia, when Labetalol alone is insufficient
• Acute severe HTN (oral, when IV not available)

Blocks L-type Ca²⁺ channels in vascular smooth muscle → arteriolar dilation → ↓ SVR → ↓ BP. Minimal cardiac effect at therapeutic doses.

• F — Flushing
• L — Leg (ankle) oedema
• A — Ache (headache)
• S — Speeding heart (reflex tachycardia)
• H — Hypotension if combined w/ MgSO₄

Maintenance (MR)

20–40 mg BD

Acute severe HTN

10 mg PO, repeat after 30 min if needed

Max acute

40–50 mg within 4 h

• AbsoluteCardiogenic shock
• AbsoluteSevere aortic stenosis
• CautionAvoid sublingual / immediate-release (precipitous drop)

• Ankle oedema (counsel — not pre-eclampsia)
• Headache, flushing
• Reflex tachycardia
• Constipation

• • No teratogenic signal.
• • Crosses placenta — monitor neonatal BP & feeding.
• • Safe in breastfeeding (low milk transfer).

• IV MgSO₄

  Caution

  Synergistic hypotension & neuromuscular blockade

• Grapefruit juice

  Caution

  ↑ levels via CYP3A4 inhibition

• Labetalol

  OK

  Safe combination in resistant HTN

• 💡 Counsel: ankle swelling is a drug effect, NOT worsening pre-eclampsia.
• 💡 Never use short-acting/sublingual nifedipine — RCOG explicitly warns against it.