Adult: 1-1.5 mg/kg via inj over at least 30 seconds, repeated at hrly intervals, as necessary. Alternatively, an initial dose of 2-5 mg/min via infusion, reduced to 1-3 mg/min according to response. Max total: 4 mg/kg.
Intravenous Acute respiratory failure
Adult: 1.5-4 mg/min via infusion, adjusted according to response.
Incompatibility
Incompatible w/ ascorbic acid, cefoperazone, cefotaxime, cefotetan, cefuroxime, clindamycin, folic acid, dexamethasone, diazepam, hydrocortisone, methylprednisolone. May form precipitate or gas w/ alkaline soln (e.g. thiopental Na, Na bicarbonate, furosemide, or aminophylline.
Contraindications
Severe HTN, status asthmaticus, coronary artery disease, epilepsy and other convulsive disorders, cerebral oedema, CVA, hyperthyroidism/thyrotoxicosis, physical obstruction of the resp tract, head injury, known or suspected pulmonary embolism. Patients on mechanical ventilation.
Special Precautions
Patient w/ cerebrovascular disease, hypermetabolic states (e.g. phaeochromocytoma), HTN. Hepatic or renal impairment.
Monitor heart rate, BP, deep tendon reflexes, CNS status, ECG. Measure arterial blood gas and pH frequently during treatment.
Overdosage
Symptoms: HTN, tachycardia and other arrhythmias, skeletal muscle hyperactivity including enhanced deep tendon reflexes, dyspnoea, cough, confusion, agitation, sweating; clonic and generalised seizure may occur. Management: Symptomatic treatment. IV diazepam, phenytoin, and short-acting barbiturates may be given, along w/ oxygen and resuscitative equipment.
Drug Interactions
Additive pressor effect when concurrently used w/ MAOIs or sympathomimetics. May temporarily mask the residual effect when used w/ neuromuscular blocking agents. May cause increased CNS stimulation, agitation, muscle fasciculation and hyperactivity w/ concurrent use of aminophylline/theophylline. Cardiac arrhythmias may occur when given w/ anaesthetics that are known to sensitise the myocardium to catecholamines (e.g. enflurane, halothane, isoflurane), delay initiation of doxapram for at least 10 min after discontinuance of anaesthesia.
Action
Description: Mechanism of Action: Doxapram stimulates respiration through action on peripheral carotid chemoreceptors. It also directly stimulates the central respiratory center in medulla w/ progressive stimulation of other parts of the brain and spinal cord at higher doses. Onset: Resp stimulation: 20-40 seconds. Duration: 5-12 min. Pharmacokinetics: Distribution: Rapidly distributed into the tissues. Metabolism: Extensively metabolised in the liver via ring hydroxylation to active metabolite, keto-doxapram. Excretion: Mainly via faeces (as unchanged drug and metabolites) and also via urine (<60>5%). Elimination half-life: 3.4 hr (mean); 2.4-4.1hr (range).
R07AB01 - doxapram ; Belongs to the class of respiratory stimulants. Used in treatment of respiratory diseases.
References
Anon. Doxapram. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 17/11/2016.Buckingham R (ed). Doxapram Hydrochloride. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com . Accessed 17/11/2016.Dopram Injection (West-ward Pharmaceutical Corp.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 17/11/2016.Joint Formulary Committee. Doxapram Hydrochloride . British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 17/11/2016.McEvoy GK, Snow EK, Miller J et al (eds). Doxapram Hydrochloride. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 17/11/2016.