Can torsemide be used in pregnancy?

Torsemide Use in Pregnancy

Torsemide should be avoided during pregnancy unless absolutely necessary for severe maternal cardiac or renal failure, as there is insufficient human safety data and diuretics can compromise uteroplacental perfusion.

Evidence from FDA Drug Labeling

The FDA label for torsemide provides critical information about pregnancy use 1:

• No human pregnancy data exists to assess the risk of major birth defects or miscarriage 1
• Animal studies show no teratogenicity at doses 10 times the human dose (rats) and 1.7 times the human dose (rabbits) 1
• At higher doses (50 times human dose in rats, 6.8 times in rabbits), fetal toxicity occurred including decreased body weight, increased resorption, and delayed ossification 1
• The estimated background risk in the U.S. general population is 2-4% for major malformations and 15-20% for miscarriage 1

Guideline Recommendations on Diuretics in Pregnancy

The use of diuretics during pregnancy is controversial and generally restricted 2:

• Diuretics reduce plasma volume expansion, raising concerns they may promote pre-eclampsia 2
• Diuretics should only be used in combination with other drugs, particularly when vasodilators cause fluid retention 2
• Diuretics are contraindicated in pre-eclampsia because uteroplacental perfusion is already reduced with fetal growth retardation 2
• If a diuretic is needed, thiazides are preferred over loop diuretics 2

When Loop Diuretics May Be Considered

Loop diuretics have limited acceptable indications in pregnancy 2:

• Furosemide (not torsemide specifically) has been used safely in pregnancy complicated by renal or cardiac failure 2
• Loop diuretics may be necessary for volume overload in pregnant women with renal disease requiring salt restriction or dialysis 2

Single Case Report with Torsemide

One 2021 case report describes successful torsemide use for severe lymphorrhea in the third trimester 3:

• A 32-year-old woman at 31 weeks with anasarca and lower extremity lymphorrhea was treated with torsemide after furosemide proved minimally effective 3
• Torsemide provided superior diuresis and symptom control compared to furosemide 3
• No adverse maternal, fetal, or neonatal outcomes occurred, with delivery of a healthy 2,920g infant at 37 weeks 3
• The authors emphasized that further study is needed to assess safe use of loop diuretics in pregnancy 3

Clinical Decision Algorithm

When considering torsemide in pregnancy:

1. Rule out all contraindications: Confirm absence of pre-eclampsia, fetal growth restriction, or uteroplacental insufficiency 2

2. Assess absolute necessity: Reserve for life-threatening maternal conditions such as severe cardiac failure or renal failure with volume overload that has failed conservative management 2

3. Consider alternatives first:

   • If diuretic needed, thiazides are preferred over loop diuretics 2
   • If loop diuretic required, furosemide has more established safety data than torsemide 2

4. Use lowest effective dose for shortest duration if torsemide is deemed essential 1

5. Monitor closely: Assess maternal volume status, fetal growth, and amniotic fluid volume 2

Important Caveats

• Diuretics can suppress lactation and torsemide presence in breast milk is unknown 1
• The longer duration of action of torsemide (3-4 hours half-life) compared to furosemide may theoretically provide more sustained diuresis 4, 5, but this has not been studied in pregnancy
• No data exists on torsemide effects on uteroplacental blood flow, which is a critical concern with all diuretics in pregnancy 2