Last update Sept. 17, 2022

Glycerol Phenylbutyrate; Sodium Phenylbutyrate

Low Risk

Possibly safe. Probably compatible. Mild risk possible. Follow up recommended. Read the Comment.

It is a drug that decreases elevated plasma levels of glutamine and ammonium in patients with urea cycle disorders. Oral administration before meals.

Since the last update we have not found published data on its excretion in breastmilk.

Its rapid metabolism to phenylacetate and short elimination half-life make it highly unlikely that clinically significant amounts will pass into breast milk.

It is a medication for use since the neonatal period.

With the correct dosage, side effects are not frequent or serious. The possibility of breastfeeding will depend more on the underlying disease and the clinical status of the mother.




We do not have alternatives for Glycerol Phenylbutyrate; Sodium Phenylbutyrate.

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

Glycerol Phenylbutyrate; Sodium Phenylbutyrate is also known as

Glycerol Phenylbutyrate; Sodium Phenylbutyrate in other languages or writings:


Glycerol Phenylbutyrate; Sodium Phenylbutyrate belongs to this group or family:


Main tradenames from several countries containing Glycerol Phenylbutyrate; Sodium Phenylbutyrate in its composition:


Variable Value Unit
Molecular weight 531 / 186 daltons
Protein Binding 82 %
pKa 4.81 -
Tmax 1 - 3.74 hours
0.76 - 1.15 hours


  1. EMA. Fenilbutirato. Ficha técnica. 2021 Full text (in our servers)
  2. FDA. Phenylbutyrate. Drug Summary. 2008 Full text (in our servers)

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