DOPRAM- doxapram hydrochloride injection
Baxter Healthcare Corporation
DESCRIPTION
DOPRAM Injection (doxapram hydrochloride injection, USP) is a clear, colorless, sterile, non-pyrogenic, aqueous solution with pH 3.5 to 5, for intravenous administration.
Each 1 mL contains:
Doxapram Hydrochloride, USP ���������������������.. 20 mg
Benzyl Alcohol, NF (as preservative) ������������������� 0.9%
Water for Injection, USP ���..����������������������.. q.s.
Doxapram Injection is a respiratory stimulant.
Doxapram hydrochloride is a white to off-white, crystalline powder, sparingly soluble in water, alcohol and chloroform. Chemically, doxapram hydrochloride is 1-ethyl-4-[2-(4-morpholinyl)ethyl]-3,3-diphenyl-2-pyrrolidinone monohydrochloride, monohydrate.
The chemical structure is:
Dopram Injection Structural Formula
(click image for full-size original)
C24 H31 ClN2 O2 � H2 O M.W. 432.98
CLINICAL PHARMACOLOGY
Pharmacodynamics
Doxapram hydrochloride produces respiratory stimulation mediated through the peripheral carotid chemoreceptors. As the dosage level is increased, the central respiratory centers in the medulla are stimulated with progressive stimulation of other parts of the brain and spinal cord. The onset of respiratory stimulation following the recommended single intravenous injection of doxapram hydrochloride usually occurs in 20 to 40 seconds with peak effect at 1 to 2 minutes. The duration of effect may vary from 5 to 12 minutes. The respiratory stimulant action is manifested by an increase in tidal volume associated with a slight increase in respiratory rate.
A pressor response may result following doxapram administration. Provided there is no impairment of cardiac function, the pressor effect is more marked in hypovolemic than in normovolemic states. The pressor response is due to the improved cardiac output rather than peripheral vasoconstriction. Following doxapram administration, an increased release of catecholamines has been noted.
Although opiate-induced respiratory depression is antagonized by doxapram, the analgesic effect is not affected.
Pharmacokinetics
Doxapram is metabolized via ring hydroxylation to ketodoxapram, an active metabolite readily detected in the plasma.
INDICATIONS AND USAGE
Postanesthesia
When the possibility of airway obstruction and/or hypoxia have been eliminated, doxapram may be used to stimulate respiration in patients with drug-induced postanesthesia respiratory depression or apnea other than that due to muscle relaxant drugs.
To pharmacologically stimulate deep breathing in the postoperative patient. (A quantitative method of assessing oxygenation, such as pulse oximetry, is recommended.)
Drug-Induced Central Nervous System Depression
Exercising care to prevent vomiting and aspiration, doxapram may be used to stimulate respiration, hasten arousal, and to encourage the return of laryngopharyngeal reflexes in patients with mild to moderate respiratory and CNS depression due to drug overdosage.
Chronic Pulmonary Disease Associated with Acute Hypercapnia
Doxapram is indicated as a temporary measure in hospitalized patients with acute respiratory insufficiency superimposed on chronic obstructive pulmonary disease. Its use should be for a short period of time (see DOSAGE AND ADMINISTRATION) as an aid in the prevention of elevation of arterial CO2 tension during the administration of oxygen.
It should not be used in conjunction with mechanical ventilation.