Last update April 15, 2024

Diltiazem Hydrochloride


Safe substance and/or breastfeeding is the best option.

It is a benzothiazepine-type calcium channel blocker and a class IV antiarrhythmic. It is used to treat hypertension and chronic stable angina. Oral or intravenous administration. It is also used topically in the treatment of anal fissure.

It is excreted in breast milk in a clinically non-significant amount. (Okada 85)

Two 6 months-old breastfed twins whose mother was treated with diltiazem did not get into health problems. (Lubbe 87)

Evidence on other antihypertensive drugs of the same family with similar structure, pharmacokinetics and action profile (nifedipine, nimodipine, nicardipine) has shown that they are excreted into milk in non-significant amount.

Diltiazem does not have any influence on prolactin production. (Velardo 1992)

Several medical societies and expert authors consider the use of this medication possible during breastfeeding. (Hale, LactMed, Briggs 2015, Schaefer 2015, Serrano 2015, Rowe 2013). American Academy of Pediatrics: medication usually compatible with breastfeeding. (AAP 2001)

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


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

Diltiazem Hydrochloride in other languages or writings:


Variable Value Unit
Oral Bioavail. 42 ± 18 (24 - 74) %
Molecular weight 451 daltons
Protein Binding 80 %
VD 5.3 ± 1.7 l/Kg
pKa 12.86 -
Tmax 3 - 8 hours
3.2 ± 1.3 hours
M/P ratio 1 -
Theoretical Dose 0.03 mg/Kg/d
Relative Dose 0.9 %
Ped.Relat.Dose 1.5 %


  1. LactMed. Drugs and Lactation Database (LactMed). Internet. Bethesda (MD): National Library of Medicine (US); 2006-. Available from: 2006 - Consulted on April 16, 2024 Full text (link to original source)
  2. Hale TW. Medications & Mothers' Milk. 1991- . Springer Publishing Company. Available from Consulted on April 10, 2024 Full text (link to original source)
  3. Briggs GG, Freeman RK, Towers CV, Forinash AB. Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk. Wolters Kluwer Health. Tenth edition (acces on line) 2015
  4. Serrano Aguayo P, García de Quirós Muñoz JM, Bretón Lesmes I, Cózar León MV. Tratamiento de enfermedades endocrinológicas durante la lactancia. [Endocrinologic diseases management during breastfeeding.] Med Clin (Barc). 2015 Jan 20;144(2):73-9. Abstract
  5. Schaefer C, Peters P, Miller RK. Drugs During Pregnancy and Lactation. Treatment options and risk assessment. Elsevier, Third Edition. 2015
  6. Rowe H, Baker T, Hale TW. Maternal medication, drug use, and breastfeeding. Pediatr Clin North Am. 2013 Feb;60(1):275-94. Abstract
  7. Velardo A, Ricci S, Zironi C, Pantaleoni M, Zizzo G, Badiali A, Marrama P. Effects of prolonged treatment with diltiazem on pituitary secretion of luteinizing hormone, follicle-stimulating hormone, thyrotropin and prolactin. Horm Res. 1992 Abstract
  8. Lubbe WF. Use of diltiazem during pregnancy. N Z Med J. 1987 Abstract
  9. Okada M, Inoue H, Nakamura Y, Kishimoto M, Suzuki T. Excretion of diltiazem in human milk. N Engl J Med. 1985 Abstract
  10. Hermann P, Rodger SD, Remones G, Thenot JP, London DR, Morselli PL. Pharmacokinetics of diltiazem after intravenous and oral administration. Eur J Clin Pharmacol. 1983 Abstract

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