doxapram hydrochloride

Action

Activates peripheral carotid, aortic, and other chemoreceptors to stimulate respiration. Increases tidal volume and respiratory rate by directly stimulating respiratory center in medulla oblongata.

Availability

Injection: 20 mg/ml

Indications and dosages

➣ Respiratory depression after anesthesia

Adults and adolescents: 5 mg/minute by I.V. infusion until desired response occurs; then reduce to 1 to 3 mg/minute, to a maximum cumulative dosage of 4 mg/kg (or 300 mg). Or 0.5 to 1 mg/kg I.V. injection, repeated q 5 minutes, if needed, to a maximum total dosage of 1.5 mg/kg.

➣ Chronic pulmonary disease related to acute hypercapnia

Adults: 1 to 2 mg/minute by I.V. infusion, using a concentration of 2 mg/ml, to a maximum of 3 mg/minute. Infusion shouldn't exceed 2 hours.

➣ Drug-induced CNS depression

Adults: Initially, 2 mg/kg I.V., repeated in 5 minutes and then q 1 to 2 hours until patient awakens, to a maximum daily dosage of 3 g. For infusion, priming dose of 2 mg/kg I.V.; if no response occurs, continue for 1 to 2 hours as needed; if some response occurs, give I.V. infusion of 250 mg in 250 ml of saline solution or dextrose 5% in water at 1 to 3 mg/minute until patient awakens. Don't infuse longer than 2 hours or give more than 3 g/day.

Off-label uses

• Laryngospasm secondary to postoperative tracheal extubation

• Apnea of prematurity

• Postoperative shivering

Contraindications

• Hypersensitivity to drug

• Cardiovascular disorders, severe hypertension

• Cerebrovascular accident

• Head injury, seizures

• Respiratory failure, restrictive respiratory disease

• Neonates

Precautions

Use cautiously in:

• bronchial asthma, arrhythmias, increased intracranial pressure, hyperthyroidism, pheochromocytoma, metabolic disorders

• concurrent use of mechanical ventilation

• pregnant or breastfeeding patients.

Administration

• Ensure adequate airway and oxygenation before administering.

• Give I.V. slowly to avoid hemolysis.

• Know that doxapram is compatible with 5% and 10% dextrose in water and with normal saline solution.

See Don't mix with thiopental sodium, bicarbonate, or aminophylline, because precipitates or gas may form.

Adverse reactions

CNS: weakness, dizziness, drowsiness, headache, dysarthria, dysphonia, disorientation, hyperactivity, paresthesia, loss of consciousness, seizures

CV: hypotension, bradycardia, chest pain or tightness, heart rate changes, thrombophlebitis, atrioventricular block, arrhythmias, cardiac arrest

EENT: lacrimation, diplopia, miosis, conjunctival hyperemia, sneezing, laryngospasm

GI: nausea, vomiting, diarrhea, abdominal cramps, increased salivation, dysphagia

GU: urinary frequency or incontinence, albuminuria

Musculoskeletal: muscle cramps, fasciculations

Respiratory: dyspnea, increased secretions, cough, hyperventilation, tachypnea, rebound hypoventilation bronchospasm

Skin: rash, diaphoresis, flushing

Other: burning or hot sensation in genitalia and perineal areas, hiccups

Interactions

Drug-drug. General anesthetics: increased risk of self-limiting arrhythmias

MAO inhibitors, sympathomimetics: potentiation of adverse cardiovascular effects

Skeletal muscle relaxants: masking of residual effects of these drugs

Drug-diagnostic tests. Blood urea nitrogen: increased level

Erythrocytes, hematocrit, hemoglobin, red blood cells, white blood cells: decreased levels

Patient monitoring

• Assess blood pressure, pulse, deep tendon reflexes, airway, and arterial blood gas values before starting therapy and frequently during infusion.

• Monitor I.V. site frequently for irritation and thrombophlebitis.

See Discontinue infusion immediately if hypotension or dyspnea suddenly develops.

Patient teaching

• Instruct patient to report adverse reactions promptly.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.