Usage
- Bambuterol is prescribed for the long-term management of persistent asthma and other airway-related problems like chronic bronchitis and emphysema, where bronchospasm is a complicating factor. It is not suitable for acute asthma attacks.
- Pharmacological Classification: Long-acting beta2-adrenergic agonist (LABA) bronchodilator, prodrug of terbutaline.
- Mechanism of Action: Bambuterol is metabolized to terbutaline. Terbutaline stimulates beta2-adrenergic receptors in the lungs, leading to relaxation of bronchial smooth muscle and widening of the airways. This improves airflow and relieves symptoms like wheezing, shortness of breath, and chest tightness.
Alternate Names
- Bambec® is a common brand name. No alternate generic names found in the provided sources.
How It Works
- Pharmacodynamics: Bambuterol’s primary effect is bronchodilation. After oral administration, approximately 20% is absorbed. The presence of food does not affect absorption rates. It is then slowly hydrolyzed (by plasma cholinesterase) and oxidized into its active metabolite, terbutaline. About 1/3 of the absorbed dose is metabolized in the intestinal wall and liver primarily to intermediary metabolites. Roughly 10% of the administered dose is converted to terbutaline in adults. Children have reduced clearance but generate less terbutaline compared to adults.
- Pharmacokinetics: The effect of bambuterol lasts for at least 24 hours. Steady-state plasma concentration is achieved after 4 to 5 days of consistent administration. Bambuterol has a plasma half-life of approximately 13 hours, while terbutaline has a half-life of approximately 21 hours. The degree to which bambuterol binds to plasma proteins is low (about 40-50%).
- Mode of Action: Bambuterol acts as a prodrug. Its active metabolite, terbutaline, selectively stimulates beta2-adrenergic receptors in the bronchial smooth muscle. Upon binding, terbutaline activates intracellular signaling pathways that ultimately lead to smooth muscle relaxation and bronchodilation.
- Elimination Pathways: Bambuterol and its metabolites, including terbutaline, are primarily excreted through the kidneys. Therefore, dose adjustments are necessary for patients with renal impairment.
Dosage
Standard Dosage
Adults:
- Initial dose: 10 mg once daily at bedtime.
- Maintenance dose: May be increased to 20 mg once daily after 1-2 weeks if needed. Patients who tolerate beta2-agonists well may start at 20 mg.
Children:
- 2-5 years: 10 mg (10 ml syrup) once daily.
- 6-12 years: 10 mg (10 ml syrup) once daily, may be increased to 20 mg if necessary after 1-2 weeks.
- Note: Safety and efficacy in children younger than 2 years have not been established. Oriental children may require lower doses due to pharmacokinetic differences.
Special Cases:
- Elderly Patients: No dose adjustment is typically required.
- Patients with Renal Impairment (moderate to severe): Initial dose should be halved (5 mg).
- Patients with Hepatic Dysfunction (severe): Bambuterol is not recommended due to unpredictable conversion to terbutaline. Terbutaline is preferred in these patients.
- Patients with Comorbid Conditions: Caution is advised in patients with diabetes, cardiovascular disease (especially ischemic heart disease, arrhythmia, severe heart failure), hyperthyroidism, hypertrophic cardiomyopathy, or predisposition to angle-closure glaucoma. Additional blood sugar monitoring may be needed in patients with diabetes.
Clinical Use Cases
- Bambuterol is not recommended for use in acute situations like intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations like status epilepticus or cardiac arrest. It’s intended for long-term management of chronic respiratory conditions.
Dosage Adjustments
- Adjust dosage based on patient response and tolerability.
- Reduce dose in patients with renal impairment. Avoid use in severe hepatic impairment.
Side Effects
Common Side Effects:
- Headache
- Restlessness or shakiness
- Tremor
- Palpitations
- Insomnia
- Muscle cramps
- Dizziness
- Nausea
Rare but Serious Side Effects:
- Allergic reactions (rash, hives, swelling)
- Difficulty breathing
- Paradoxical bronchospasm
- Cardiac arrhythmias
- Myocardial ischemia
- Hypokalemia
- Hyperglycemia
Long-Term Effects:
- No specific long-term effects have been identified in the provided resources, but ongoing monitoring is recommended.
Adverse Drug Reactions (ADR):
- Severe allergic reaction
- Significant changes in heart rate or rhythm
- Worsening of respiratory symptoms
Contraindications
- Hypersensitivity to bambuterol.
- Severe hepatic impairment or liver cirrhosis.
- Pregnancy (use with caution, if at all, especially at the end of pregnancy, as it can relax the uterus).
Drug Interactions
- Beta-blockers: May antagonize the bronchodilatory effects of bambuterol.
- Other sympathomimetics: May potentiate cardiovascular side effects.
- Corticosteroids, diuretics, xanthine derivatives: May increase the risk of hypokalemia.
- Succinylcholine and other cholinesterase-dependent drugs: Bambuterol inhibits cholinesterase and may prolong their duration of action.
- Non-depolarizing neuromuscular blockers (e.g., vecuronium): Bambuterol may enhance their effects.
- Other possible interactions: steroids (e.g., prednisolone), theophylline, aminophylline, timolol, ipratropium, furosemide, amiloride, bumetanide.
Pregnancy and Breastfeeding
- Pregnancy: Not recommended, especially at the end of pregnancy. The safety of bambuterol during pregnancy has not been established.
- Breastfeeding: Terbutaline, the active metabolite of bambuterol, is excreted in breast milk. While the effect on the infant is likely minimal at therapeutic doses, caution is advised. Discuss the risks and benefits with the patient.
Drug Profile Summary
- Mechanism of Action: Prodrug metabolized to terbutaline, a beta2-agonist that relaxes bronchial smooth muscle.
- Side Effects: Headache, tremor, palpitations, insomnia, muscle cramps, hypokalemia, hyperglycemia.
- Contraindications: Hypersensitivity, severe hepatic impairment, pregnancy.
- Drug Interactions: Beta-blockers, other sympathomimetics, corticosteroids, diuretics, xanthine derivatives, succinylcholine, non-depolarizing neuromuscular blockers.
- Pregnancy & Breastfeeding: Not recommended.
- Dosage: Adults: 10-20 mg once daily at bedtime. Children: Dosage depends on age and ethnicity.
- Monitoring Parameters: Pulmonary function tests (e.g., peak expiratory flow rate, FEV1, FVC), blood pressure, heart rate, blood glucose, potassium levels.
Popular Combinations
- Inhaled corticosteroids: Bambuterol should be used in conjunction with inhaled corticosteroids for long-term asthma control.
Precautions
- General Precautions: Evaluate for pre-existing medical conditions, such as diabetes, liver or kidney disease, heart conditions, hyperthyroidism and glaucoma. Screen for allergies.
- Pregnant Women: Avoid use. If necessary, use with extreme caution.
- Breastfeeding Mothers: Not recommended.
- Children & Elderly: Follow pediatric dosage guidelines. Monitor elderly patients for potential adverse effects.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Bambuterol?
A: Adults: 10-20 mg once daily at bedtime. Children (2-5 years): 10 mg once daily. Children (6-12 years): 10-20 mg once daily. Dosages should be adjusted for patients with renal impairment or specific ethnicities. Not recommended for patients with severe liver impairment.
Q2: How does Bambuterol work?
A: It’s a prodrug converted to terbutaline, which stimulates beta2 receptors in the lungs, relaxing the airways and improving breathing.
Q3: What are the common side effects of Bambuterol?
A: Common side effects include headache, tremor, palpitations, insomnia, and muscle cramps.
Q4: Can Bambuterol be used during pregnancy?
A: It is generally contraindicated in pregnancy, especially in the later stages.
Q5: Is Bambuterol safe for patients with liver problems?
A: No. It’s contraindicated in patients with severe hepatic impairment or liver cirrhosis.
Q6: What are the potential drug interactions with Bambuterol?
A: Interactions can occur with beta-blockers, other sympathomimetics, diuretics, corticosteroids, xanthine derivatives, and drugs metabolized by cholinesterase.
Q7: Can Bambuterol be used to treat an acute asthma attack?
A: No, it is for long-term management of persistent asthma and should not be used for acute attacks.
Q8: How should Bambuterol be taken?
A: Orally, once daily, preferably at bedtime.
Q9: Does Bambuterol have any effect on blood sugar levels?
A: It can cause hyperglycemia, especially in patients with diabetes. Monitoring is recommended.
Q10: Are there any specific precautions for elderly patients taking Bambuterol?
A: While no specific dose adjustment is usually necessary, they should be monitored closely for side effects.
