Doxapram is a specific respiratory stimulant. It stimulates the respiratory center preferentially and has relatively less effect on cortical and spinal sites. Following intravenous doxapram injection the drug stimulates ventilation and increases cardiac output and work.
It is given in a dose of 1-1.5 mg/kg by intravenous injection.
Intravenous infusion can also be given as 0.2% solution in 5% dextrose at a rate 1.5-3 mg/min.
The drug has a brief duration of action, only 5-10 min, following a single dose.
The drug is rapidly inactivated in the liver, partly metabolized and partly excreted unchanged in urine.
It can reverse the drug-induced respiratory depression. It may even cause arousal of anesthesia. Respiratory stimulation is not usually followed by depression. This hyperpnea may aid blind nasal intubation. Its use has been advocated to reduce the incidence of apneic attacks in premature infants.
Doxapram injection has a selective effect on peripheral chemoreceptors in the carotid sinus. It stimulates the respiratory center more than the cerebral cortex. It has a wider therapeutic ratio than most other analeptic drugs.
Doxapram injection may be used as an adjunct to opiate analgesia; it does not reverse the analgesic effect but can overcome the respiratory depression.
Doxapram side effects
Side effects like muscle twitching and convulsion are rare in therapeutic doses.
It has a high ratio (70:1) between convulsant and respiratory stimulant dose in comparison to that of nikethamide (18:1).
The drug seems to be contraindicated in patients with ischemic heart disease or with severe hypertension.
During anesthesia it may induce cardiac arrhythmia. It should not be used in cases with thyrotoxicosis and status asthmaticus. Its action is potentiated by MAO inhibitors.