Last update May 20, 2024

1-Hydrazinophthalazine hydrochloride


Safe substance and/or breastfeeding is the best option.

Peripheral vasodilator. Indicated in the treatment of arterial hypertension and heart failure. Oral administration every 6 to 12 hours. Intravenous use in hypertensive emergencies.

It is excreted into breast milk in clinically non-significant amount (Lamont 1986, Franke 1986, Liedholm 1982). No problem was observed in infants whose mothers were on this medication. (AEMPS 2012)

Plasma levels in those infants were undetectable or very low, between 15 and 30 times lower than those observed in neonates after therapeutic use. (Lamont 1986)

Several medical societies, experts and expert consensus, consider the use of this medication safe during breastfeeding (Kearney 2018, Anderson 2018, Malachias 2016, Ghanem 2008). The American Academy of Pediatrics rates it as a medication usually compatible with breastfeeding (AAP 2001). WHO List of Essential Medicines 2002: compatible with breastfeeding. (WHO 2002)


  • Enalapril (Safe substance and/or breastfeeding is the best option.)
  • Methyldopa (Safe substance and/or breastfeeding is the best option.)
  • Propranolol (Safe substance and/or breastfeeding is the best option.)

Suggestions made at e-lactancia are done by APILAM team of health professionals, and are based on updated scientific publications. It is not intended to replace the relationship you have with your doctor but to compound it. The pharmaceutical industry contraindicates breastfeeding, mistakenly and without scientific reasons, in most of the drug data sheets.

Jose Maria Paricio, Founder & President of APILAM/e-Lactancia

Your contribution is essential for this service to continue to exist. We need the generosity of people like you who believe in the benefits of breastfeeding.

Thank you for helping to protect and promote breastfeeding.

José María Paricio, founder of e-lactancia.

Other names

1-Hydrazinophthalazine hydrochloride is Hydralazine Hydrochloride in Chemical name.

Is written in other languages:


1-Hydrazinophthalazine hydrochloride belongs to these groups or families:


Main tradenames from several countries containing 1-Hydrazinophthalazine hydrochloride in its composition:


Variable Value Unit
Oral Bioavail. 10 - 35 %
Molecular weight 197 daltons
Protein Binding 90 %
VD 1.6 l/Kg
pKa 6.4 -
Tmax 1 - 2 hours
0.7 - 3.6 hours
M/P ratio 0.5 - 1.4 -
Theoretical Dose 0.026 mg/Kg/d
Relative Dose 1.5 - 3.8 %
Ped.Relat.Dose 0.7 - 1.5 %


  1. Anderson PO. Treating Hypertension During Breastfeeding. Breastfeed Med. 2018 Abstract
  2. Kearney L, Wright P, Fhadil S, Thomas M. Postpartum Cardiomyopathy and Considerations for Breastfeeding. Card Fail Rev. 2018 Abstract Full text (link to original source) Full text (in our servers)
  3. Amdipharm. Hydralazine. Drug Summary. 2017 Full text (in our servers)
  4. Malachias MV, Figueiredo CE, Sass N, Antonello IC, Torloni MR, Bortolotto MRF L. 7th Brazilian Guideline of Arterial Hypertension: Chapter 9 - Arterial Hypertension in pregnancy Arq Bras Cardiol. 2016 Abstract Full text (link to original source)
  5. AEMPS-Rubio. Hidralazina. Ficha técnica. 2012 Full text (in our servers)
  6. Ghanem FA, Movahed A. Use of antihypertensive drugs during pregnancy and lactation. Cardiovasc Ther. 2008 Abstract Full text (link to original source) Full text (in our servers)
  7. WHO / UNICEF. BREASTFEEDING AND MATERNAL MEDICATION Recommendations for Drugs in the Eleventh WHO Model List of Essential Drugs. Department of Child and Adolescent Health and Development (WHO/UNICEF) 2002 Abstract Full text (link to original source) Full text (in our servers)
  8. AAP - American Academy of Pediatrics Committee on Drugs. Transfer of drugs and other chemicals into human milk. Pediatrics. 2001 Sep;108(3):776-89. Abstract Full text (link to original source) Full text (in our servers)
  9. Franke G, Pietsch P, Schneider T, Siegmund W, Grabow D, Schütz H. Studies on the kinetics and distribution of dihydralazine in pregnancy. Biol Res Pregnancy Perinatol. 1986 Abstract
  10. Lamont RF, Elder MG. Transfer of hydralazine across the placenta and into breast milk. J Obstet Gynaecol. 1986 Abstract
  11. Liedholm H, Wåhlin-Boll E, Hanson A, Ingemarsson I, Melander A. Transplacental passage and breast milk concentrations of hydralazine. Eur J Clin Pharmacol. 1982 Abstract

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