Calfactant is a lung surfactant for the prophylaxis of respiratory distress syndrome in high-risk infants.

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Generic Name
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Calfactant is a sterile, non-pyrogenic lung surfactant intended for intratracheal instillation. It is an off-white suspension of an extract of natural surfactant from calf lungs suspended in 0.9% saline. Each milliliter of calfactant contains 35mg of phospholipids (including 26 mg phosphatidylcholine of which 16 mg is disaturated phosphatidylcholine) and 0.65mg of proteins including surfactant-associated proteins B and C.

Calfactant is approved for use in the United States of America. It is used to prevent or treat respiratory distress syndrome in premature infants with lung surfactant deficiency. Calfactant has been shown to decrease the incidence of respiratory distress syndrome, mortality due to respiratory distress syndrome, and air leaks associated with respiratory distress syndrome in clinical trials. It adsorbs to the air:fluid interface in the lungs and works to reduce surface tension, in a manner similar to endogenous pulmonary surfactant.

Small Molecule
  • AeroFact
  • Alveofact
  • Bovactant
  • Calf lung surfactant extract (CLSE)
  • Calfactant
  • SF-RI 1



Calfactant is indicated for prophylaxis therapy to prevent respiratory distress syndrome (RDS) in premature infants <29 weeks of gestational age with low lung surfactant and at high risk for RDS. Calfactant therapy is also indicated for the treatment of respiratory distress syndrome in infants 72 hours or less of age with RDS confirmed by clinical and radiologic findings and requiring endotracheal intubation.

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Associated Conditions
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Not Available

Mechanism of action

Pulmonary surfactant is an endogenous substance produced in the lungs that functions to decrease surface tension at the air:fluid interface on the alveolar surface. In premature infants with pulmonary surfactant deficiency, surface tension can increase to the point where sections of lung collapse and respiratory distress syndrome (RDS) develops. Calfactant adsorbs rapidly to the surface of the alveolar air:fluid interface and modifies surface tension to a minimum of less than 3 mN/m. It acts in a manner similar to natural lung surfactant, thus preventing or treating respiratory distress syndrome.


Calfactant is administered directly to the lung lumen surface where it acts. No human studies on absorption have been completed.

Volume of distribution

No human studies on the distribution of calfactant have been performed.

Protein binding

Not Available


Endogenous lung surfactant is produced and excreted by Type II alveolar pneumocytes to form a surface monolayer across the alveoli through adsorption. Through repeated contraction and expansion of an alveolus, this monolayer degrades and the surfactant is taken back up into the Type II alveolar pneumocyte for re-packaging. No human studies on the metabolism of calfactant have been completed, but it is likely metabolized through a similar mechanism to endogenous pulmonary surfactant.

Route of elimination

No human studies on elimination of calfactant have been completed.


Half time clearance from the lung lumen was reported as 12 hours in a study of normal rabbits.


No human studies on the metabolism and elimination of calfactant have been performed.

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Carcinogenesis and animal reproduction studies have not been performed with calfactant. A single mutagenicity study produced a negative Ames assay. Overdose with calfactant has not yet been reported, but it is recommended that in the case of an overdose ventilation should be supported until all excess fluid is cleared from the lungs. Cyanosis, bradycardia and airway obstruction have been reported with administration of calfactant.

Not Available
Pharmacogenomic Effects/ADRs
Not Available


Drug Interactions
This information should not be interpreted without the help of a healthcare provider. If you believe you are experiencing an interaction, contact a healthcare provider immediately. The absence of an interaction does not necessarily mean no interactions exist.
AcebutololAcebutolol may increase the bradycardic activities of Calfactant.
AlfentanilAlfentanil may increase the bradycardic activities of Calfactant.
AmiodaroneAmiodarone may increase the bradycardic activities of Calfactant.
AmlodipineAmlodipine may increase the bradycardic activities of Calfactant.
AtenololAtenolol may increase the bradycardic activities of Calfactant.
BendroflumethiazideBendroflumethiazide may increase the bradycardic activities of Calfactant.
BepridilBepridil may increase the bradycardic activities of Calfactant.
BeractantCalfactant may increase the bradycardic activities of Beractant.
BetaxololBetaxolol may increase the bradycardic activities of Calfactant.
BisoprololBisoprolol may increase the bradycardic activities of Calfactant.
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Food Interactions
No interactions found.


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Brand Name Prescription Products
NameDosageStrengthRouteLabellerMarketing StartMarketing EndRegionImage
InfasurfSuspension35.7 mg/1mLEndotrachealONY Biotech Inc.2011-07-21Not applicableUS flag
Mixture Products
NameIngredientsDosageRouteLabellerMarketing StartMarketing EndRegionImage
BlesCalfactant (27 mg/mL)SuspensionEndotrachealBles Biochemicals Inc2002-02-05Not applicableCanada flag
NeosurfCalfactant (27 mg/ml)SuspensionEndotrachealCipla LtdNot applicableNot applicableCanada flag


Drug Categories
Not classified
Affected organisms
  • Humans and other mammals

Chemical Identifiers

CAS number
InChI Key
Not Available
Not Available
Not Available
Not Available


Synthesis Reference

Notter RH, Wang Z, Egan EA, Holm BA: Component-specific surface and physiological activity in bovine-derived lung surfactants. Chem Phys Lipids. 2002 Jan;114(1):21-34. Pubmed.

General References
  1. Willson D: Calfactant. Expert Opin Pharmacother. 2001 Sep;2(9):1479-93. [Article]
  2. Bloom BT, Clark RH: Comparison of Infasurf (calfactant) and Survanta (beractant) in the prevention and treatment of respiratory distress syndrome. Pediatrics. 2005 Aug;116(2):392-9. [Article]
  3. Willson DF, Thomas NJ, Markovitz BP, Bauman LA, DiCarlo JV, Pon S, Jacobs BR, Jefferson LS, Conaway MR, Egan EA: Effect of exogenous surfactant (calfactant) in pediatric acute lung injury: a randomized controlled trial. JAMA. 2005 Jan 26;293(4):470-6. [Article]
  4. Attar MA, Becker MA, Dechert RE, Donn SM: Immediate changes in lung compliance following natural surfactant administration in premature infants with respiratory distress syndrome: a controlled trial. J Perinatol. 2004 Oct;24(10):626-30. [Article]
  5. Nguyen TN, Cunsolo SM, Gal P, Ransom JL: Infasurf and curosurf: theoretical and practical considerations with new surfactants. J Pediatr Pharmacol Ther. 2003 Apr;8(2):97-114. doi: 10.5863/1551-6776-8.2.97. [Article]
  6. Willson DF, Zaritsky A, Bauman LA, Dockery K, James RL, Conrad D, Craft H, Novotny WE, Egan EA, Dalton H: Instillation of calf lung surfactant extract (calfactant) is beneficial in pediatric acute hypoxemic respiratory failure. Members of the Mid-Atlantic Pediatric Critical Care Network. Crit Care Med. 1999 Jan;27(1):188-95. [Article]
  7. Logan JW, Moya FR: Animal-derived surfactants for the treatment and prevention of neonatal respiratory distress syndrome: summary of clinical trials. Ther Clin Risk Manag. 2009 Feb;5(1):251-60. Epub 2009 Mar 26. [Article]
  8. Willson DF, Truwit JD, Conaway MR, Traul CS, Egan EE: The Adult Calfactant in Acute Respiratory Distress Syndrome Trial. Chest. 2015 Aug;148(2):356-64. doi: 10.1378/chest.14-1139. [Article]
  9. McPherson C, Gal P, Ransom JL, Carlos RQ, Dimaguila MA, Smith M, Davonzo C, Wimmer JE Jr: Indomethacin pharmacodynamics are altered by surfactant: a possible challenge to current indomethacin dosing guidelines created before surfactant availability. Pediatr Cardiol. 2010 May;31(4):505-10. doi: 10.1007/s00246-009-9628-6. Epub 2010 Jan 10. [Article]
PubChem Substance
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Clinical Trials

Clinical Trials
3CompletedPreventionChronic Lung Disease of Prematurity1
3CompletedTreatmentChronic Lung Disease of Prematurity / Respiratory Distress Syndrome of Prematurity (Surfactant Dysfunction)1
3CompletedTreatmentRespiratory Distress Syndrome1
3TerminatedTreatmentRespiratory Distress Syndrome, Adult1
2RecruitingTreatmentRespiratory Distress Syndrome In Premature Infants1
2Unknown StatusPreventionChronic Lung Disease of Prematurity1
2, 3CompletedTreatmentLung Injury, Acute (ALI)1
2, 3Unknown StatusPreventionLung Transplant / Primary Graft Dysfunction1
1, 2CompletedPreventionChronic Lung Disease of Prematurity1


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Dosage Forms
SuspensionEndotracheal50 mg/1.2mL
SuspensionEndotracheal35.7 mg/1mL
SuspensionEndotracheal35 mg/mL
Not Available
Not Available


Experimental Properties
Not Available
Predicted Properties
Not Available
Predicted ADMET Features
Not Available


Mass Spec (NIST)
Not Available
Not Available

Drug created at March 19, 2008 16:32 / Updated at February 21, 2021 18:52