Last update May 20, 2024

Guanfacine Hydrochloride

Likely Compatibility

Fairly safe. Mild or unlikely adverse effects. Compatible under certain circumstances. Follow-up recommended. Read Commentary.

Central action alpha-1 adrenergic blocker with indications similar to clonidine, used in the treatment of hypertension and attention deficit hyperactivity disorder (ADHD). Oral administration once a day.

Since the last update we have not found any published data on its excretion in breast milk.

Its pharmacokinetic data (low molecular weight, low protein binding and prolonged half-life) make it likely that it would pass into breast milk in amounts which could be significant, although its very high distribution volume would make this difficult. 

It can reduce prolactin levels (Hauger 1981), but when lactation is well established, milk production does not depend so much on prolactin levels.

Until more extensive published data about this drug regarding breastfeeding are available a safer alternative drug may be used (Anderson 2018), especially during the neonatal period and/or in case of premature infants.


  • Doxazosin Mesylate (Safe substance and/or breastfeeding is the best option.)
  • Labetalol Hydrochloride (Safe substance and/or breastfeeding is the best option.)
  • Methyldopa (Safe substance and/or breastfeeding is the best option.)
  • Metoprolol (Safe substance and/or breastfeeding is the best option.)
  • Nifedipine (Safe substance and/or breastfeeding is the best option.)
  • Nimodipine (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

Guanfacine Hydrochloride in other languages or writings:


Main tradenames from several countries containing Guanfacine Hydrochloride in its composition:


Variable Value Unit
Oral Bioavail. 80 %
Molecular weight 283 daltons
Protein Binding 70 %
VD 6.3 l/Kg
pKa 12.9 -
Tmax 1 - 5 hours
17 (10 - 30) hours


  1. Anderson PO. Treating Hypertension During Breastfeeding. Breastfeed Med. 2018 Abstract
  2. EMA. Guanfacina. Ficha técnica. 2017 Full text (in our servers)
  3. EMA. Guanfacine. Drug Summary. 2017 Full text (in our servers)
  4. Hauger-Klevene JH, Pinkas MB, Gerber S. Blood pressure and prolactin: effects of guanfacine. Three-year follow-up study. Hypertension. 1981 Abstract

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