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Infasurf Dosage

Generic name: CALFACTANT 35.7mg in 1mL
Dosage form: intratracheal suspension
Drug class: Lung surfactants

Medically reviewed by Last updated on Sep 26, 2023.



Infasurf should be administered under the supervision of clinicians experienced in the acute care of newborn infants with respiratory failure who require intubation. Rapid and substantial increases in blood oxygenation and improved lung compliance often follow Infasurf instillation. Close clinical monitoring and surveillance following administration may be needed to adjust oxygen therapy and ventilator pressures appropriately.


Each dose of Infasurf is 3 mL/kg body weight at birth. Infasurf has been administered every 12 hours for a total of up to 3 doses.

Directions for Use

Infasurf is a suspension which settles during storage. Gentle swirling or agitation of the vial is often necessary for redispersion. DO NOT SHAKE. Visible flecks in the suspension and foaming at the surface are normal for Infasurf. Infasurf should be stored at refrigerated temperature 2° to 8°C (36° to 46°F). THE 3mL VIAL MUST BE STORED UPRIGHT. Date and time need to be recorded on the carton when Infasurf is removed from the refrigerator. Warming of Infasurf before administration is not necessary.

Unopened, unused vials of Infasurf that have warmed to room temperature can be returned to refrigerated storage within 24 hours for future use. I nfasurf should not be removed from the refrigerator for more than 24 hours. Infasurf should not be returned to the refrigerator more than once.Repeated warming to room temperature should be avoided. Each single-use vial should be entered only once and the vial with any unused material should be discarded after the initial entry.


Dosing Procedures


Infasurf should only be administered intratracheally through an endotracheal tube. The dose of Infasurf is 3 mL/kg birth weight. The dose is drawn into a syringe from the single-use vial using a 20-gauge or larger needle with care taken to avoid excessive foaming. Administration is made by instillation of the Infasurf suspension into the endotracheal tube.

Administration for Treatment of RDS

When used to treat RDS, Infasurf may be administered using either of the following 2 methods:

Exosurf Active Control Trials: Initial and Repeat Dosing

In the Infasurf vs. Exosurf® trials, Infasurf was administered intratracheally through a side-port adapter into the endotracheal tube. Two attendants, one to instill the Infasurf, the other to monitor the patient and assist in positioning, facilitated the dosing.

The dose (3 mL/kg) was administered in two aliquots of 1.5 mL/kg each. After each aliquot was instilled, the infant was positioned with either the right or the left side dependent. Administration was made while ventilation was continued over 20-30 breaths for each aliquot, with small bursts timed only during the inspiratory cycles. A pause followed by evaluation of the respiratory status and repositioning separated the two aliquots. Repeat doses of 3 mL/kg of birth weight, up to a total of 3 doses 12 hours apart, were given if the patient was still intubated.

Survanta Active Control Trials: Initial and Repeat Dosing

In the Infasurf vs. Survanta® trials, Infasurf was administered through a 5 French feeding catheter inserted into the endotracheal tube. The total dose was instilled in four equal aliquots with the catheter removed between each of the instillations and mechanical ventilation resumed for 0.5 to 2 minutes. Each of the aliquots was administered with the patient in one of four different positions (prone, supine, right, and left lateral) to facilitate even distribution of the surfactant. Repeat doses were administered as early as 6 hours after the previous dose for a total of up to 4 doses if the infant was still intubated and required at least 30% inspired oxygen to maintain a PaO2 less than or equal to 80 torr.

Administration for Prophylaxis of RDS at Birth

Dosing procedures are described under Administration for Treatment of RDS. The amount of a prophylaxis dose of Infasurf should be based on the infant’s birth weight. Administration of Infasurf for prophylaxis should be given as soon as possible after birth. Usually the immediate care and stabilization of the premature infant born with hypoxemia and/or bradycardia should precede Infasurf prophylaxis.

Dosing Precautions

During administration of Infasurf liquid suspension into the airway, infants often experience bradycardia, reflux of Infasurf into the endotracheal tube, airway obstruction, cyanosis, dislodgement of the endotracheal tube, or hypoventilation. If any of these events occur, the administration should be interrupted and the infant’s condition should be stabilized using appropriate interventions before the administration of Infasurf is resumed. Endotracheal suctioning or reintubation is sometimes needed when there are signs of airway obstruction during the administration of the surfactant.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.