COMBIVENT RESPIMAT
Clinical safety rating: caution
Comprehensive clinical and safety monograph for COMBIVENT RESPIMAT (COMBIVENT RESPIMAT).
Combination of ipratropium bromide (anticholinergic) and albuterol sulfate (beta-2 adrenergic agonist). Ipratropium inhibits muscarinic acetylcholine receptors, reducing bronchoconstriction and mucus secretion. Albuterol stimulates beta-2 receptors, relaxing bronchial smooth muscle and increasing cAMP.
| Metabolism | Ipratropium: partially metabolized by ester hydrolysis to inactive metabolites; Albuterol: primarily metabolized by sulfotransferase (SULT1A3) to albuterol 4'-O-sulfate. |
| Excretion | Ipratropium: primarily fecal (70-90%) via biliary excretion, renal excretion accounts for 10-20%. Salbutamol: 60-70% renal as unchanged drug and metabolites, 30-40% fecal via biliary excretion. |
| Half-life | Ipratropium: terminal half-life approximately 1.6 hours. Salbutamol: terminal half-life 3.8-6 hours (mean 4.6 hours). Clinically, inhalation allows direct airway delivery; systemic half-life not primarily responsible for bronchodilator effect. |
| Protein binding | Ipratropium: 0-9% (minimal). Salbutamol: 10-15% primarily to albumin. |
| Volume of Distribution | Ipratropium: 4.6 L/kg (large Vd indicates extensive tissue distribution). Salbutamol: 4-6 L/kg (high Vd reflects distribution into tissues). |
| Bioavailability | Inhalation: 7-14% of delivered dose reaches systemic circulation (ipratropium 7%, salbutamol 13-14%). Oral bioavailability: ipratropium <5%, salbutamol 30-40%. |
| Onset of Action | Inhalation: 15-20 minutes for significant bronchodilation. |
| Duration of Action | 4-6 hours (bronchodilation). Clinical note: duration may be shorter in acute bronchospasm. |
Two inhalations (ipratropium 18 mcg and albuterol 103 mcg per inhalation) via oral inhalation four times daily. Maximum: 12 inhalations per 24 hours.
| Dosage form | SPRAY, METERED |
| Renal impairment | No specific dose adjustment recommended for renal impairment. Use caution in patients with severe renal impairment (CrCl <30 mL/min) due to potential for systemic accumulation. |
| Liver impairment | No specific dose adjustment recommended for hepatic impairment. Use caution in severe hepatic impairment (Child-Pugh class C) as safety data are limited. |
| Pediatric use | Not established for children under 18 years. Safety and efficacy have not been determined in pediatric patients. |
| Geriatric use | No specific dose adjustment recommended. Use with caution due to increased sensitivity to anticholinergic effects (e.g., urinary retention, constipation) and beta-agonist effects (e.g., tremor, tachycardia). Monitor renal function as elderly are more prone to decreased renal function. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for COMBIVENT RESPIMAT (COMBIVENT RESPIMAT).
| Breastfeeding | Ipratropium: Minimal excretion into breast milk due to low bioavailability; M/P ratio not established. Albuterol: Excreted into breast milk in small amounts (M/P ratio ~0.6). Doses <4 puffs/day are considered compatible with breastfeeding. Monitor infant for irritability, tachycardia, and feeding difficulties. |
| Teratogenic Risk | Ipratropium bromide and albuterol sulfate. Ipratropium: No teratogenic effects in animal studies; minimal systemic absorption suggests low fetal risk. Albuterol: Inhaled beta-agonists are not associated with major malformations; risk of preterm labor and maternal hyperglycemia. First trimester: No known teratogenicity. Second/third trimesters: May cause fetal tachycardia, hypoglycemia, and hypocalcemia if used near delivery. Overall, use only if clearly needed. |
■ FDA Black Box Warning
None.
| Serious Effects |
["Hypersensitivity to ipratropium, albuterol, or any component (including atropine)","History of hypersensitivity to soya lecithin or peanuts (due to propellant)"]
| Precautions | ["Paradoxical bronchospasm","Immediate hypersensitivity reactions (anaphylaxis, urticaria)","Cardiovascular effects (increased heart rate, hypertension, QT prolongation)","Use with caution in patients with glaucoma, urinary retention, or prostatic hypertrophy","Exacerbation of diabetes and ketoacidosis with albuterol","Hypokalemia with high doses of albuterol","Not for acute deterioration or rescue therapy"] |
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| Fetal Monitoring | Monitor maternal pulmonary function, fetal heart rate, and uterine activity in patients with asthma exacerbations. Assess for signs of maternal hyperglycemia, hypokalemia, and tremors. In third trimester, monitor for preterm labor and fetal distress. Performance of fetal nonstress test or biophysical profile if indicated. |
| Fertility Effects | Albuterol: No known adverse effects on human fertility. Ipratropium: No data on fertility impairment. Animal studies show no fertility compromise. |