Usage
Tulobuterol is prescribed for the prophylaxis and control of bronchospasm in patients with asthma, chronic bronchitis, asthmatic bronchitis, pulmonary emphysema, bronchiectasis, tracheobronchitis with emphysema, and other bronchospastic disorders. It is classified as a long-acting beta2-adrenergic agonist (LABA) bronchodilator. Tulobuterol works by selectively stimulating beta2-adrenergic receptors in the bronchial smooth muscle, leading to relaxation of the airways and improved airflow.
Alternate Names
Tulobuterol hydrochloride is the chemical name. Brand names may vary depending on the region (e.g., Tuloplast, Bremax, Tulo-Touch).
How It Works
Pharmacodynamics: Tulobuterol relaxes bronchial smooth muscle by selectively binding to beta2-adrenergic receptors, activating adenylate cyclase, and increasing intracellular cyclic AMP. This cascade leads to decreased intracellular calcium levels, causing smooth muscle relaxation and bronchodilation.
Pharmacokinetics: Tulobuterol can be administered orally or transdermally (patch). Oral administration has a rapid onset of action (within 30 minutes), with peak effects in 2-3 hours. The transdermal patch provides continuous drug delivery for 24 hours. Tulobuterol undergoes extensive hepatic metabolism primarily through ring-hydroxylation. Metabolites are excreted renally, both as conjugates and unchanged drug (less than 5% of the dose). The long half-life of tulobuterol allows for once-daily dosing with the transdermal patch or twice-daily dosing with oral formulations.
Dosage
Standard Dosage
Adults:
- Oral: 1-2 mg twice daily, increased to 2 mg three times a day if needed, maximum 6 mg daily.
- Transdermal: 2 mg patch applied once daily.
Children:
- Oral: Dosing based on weight (40-80 mcg/kg/day divided twice daily).
- Transdermal: 0.5 mg patch for 6 months to 2 years, 1 mg patch for 3-8 years, 2 mg patch for 9 years and older, once daily.
- Children younger than 6 months - Use is not recommended.
Special Cases:
- Elderly Patients: Start with a lower dose (1 mg twice daily) and titrate cautiously based on clinical response.
- Patients with Renal Impairment: Caution should be exercised; dose adjustment may be required.
- Patients with Hepatic Dysfunction: Careful dose titration is recommended.
- Patients with Comorbid Conditions: Use with caution in patients with hyperthyroidism, hypertension, diabetes mellitus, or cardiovascular disorders. Atopic dermatitis might also worsen.
Clinical Use Cases
Tulobuterol’s clinical use is primarily focused on long-term management of asthma and COPD.
Dosage Adjustments
Adjustments are based on patient-specific factors, including renal/hepatic dysfunction, comorbid conditions, age, and drug response.
Side Effects
Common Side Effects
Tremor, headache, palpitations, tachycardia, rash, itching, application site reactions (erythema, itching).
Rare but Serious Side Effects
Hypersensitivity reactions, severe cardiovascular effects (arrhythmias, hypertension), hypokalemia.
Long-Term Effects
Potential for tolerance with long-term use; regular monitoring of pulmonary function is recommended.
Adverse Drug Reactions (ADR)
Severe allergic reactions (angioedema, bronchospasm), paradoxical bronchospasm, significant QT prolongation, severe hypokalemia.
Contraindications
Hypersensitivity to tulobuterol or other beta2-agonists, severe cardiovascular disorders (ischemic heart disease, arrhythmias, uncontrolled hypertension), phaeochromocytoma.
Drug Interactions
Beta-blockers (reduce bronchodilator effect), other sympathomimetic drugs (additive cardiovascular effects), theophylline (additive side effects), diuretics (increased risk of hypokalemia), digoxin (increased risk of arrhythmias), MAO inhibitors and TCAs (increased risk of hypertension).
Pregnancy and Breastfeeding
Pregnancy Safety: Consult a doctor. Use only if potential benefit outweighs risk. Limited data is available on the effects of tulobuterol in pregnancy and breastfeeding.
Drug Profile Summary
- Mechanism of Action: Selective beta2-adrenergic agonist, relaxes airway smooth muscle.
- Side Effects: Tremor, palpitations, tachycardia, headache, rash, itching, application site reactions. Rarely: hypersensitivity reactions, hypokalemia, cardiovascular effects.
- Contraindications: Hypersensitivity to tulobuterol or other beta2-agonists, severe cardiovascular diseases, phaeochromocytoma.
- Drug Interactions: Beta-blockers, other sympathomimetics, theophylline, diuretics, digoxin, MAOIs, TCAs.
- Pregnancy & Breastfeeding: Consult a doctor; limited safety data available.
- Dosage: Adults: 1-2 mg oral twice daily or 2 mg transdermal patch once daily; Pediatric dosing varies.
- Monitoring Parameters: Pulmonary function, heart rate, blood pressure, potassium levels.
Popular Combinations
Tulobuterol is often combined with inhaled corticosteroids for long-term management of asthma and COPD. The combined effect provides better control than either drug alone.
Precautions
General Precautions: Assess for pre-existing medical conditions, allergies.
Specific Populations: Caution in pregnancy, breastfeeding, children, elderly, and patients with cardiovascular, renal, or hepatic impairment.
FAQs
Q1: What is the recommended dosage for Tulobuterol?
A: Adults: 2 mg transdermal patch once daily or 1-2 mg oral twice daily. Pediatric dosing varies based on age and weight.
Q2: What is the mechanism of action of Tulobuterol?
A: Tulobuterol is a selective beta2-adrenergic agonist that relaxes airway smooth muscle, resulting in bronchodilation.
Q3: What are the common side effects of Tulobuterol?
A: Common side effects include tremor, palpitations, tachycardia, headache, rash, and itching.
Q4: What are the contraindications for Tulobuterol?
A: Contraindications include hypersensitivity to tulobuterol, severe cardiovascular disorders, and phaeochromocytoma.
Q5: How should Tulobuterol be administered?
A: Tulobuterol can be administered orally or transdermally (patch), depending on the specific formulation and patient factors.
Q6: Can Tulobuterol be used in pregnant or breastfeeding women?
A: Consult a doctor. Use only if the potential benefit outweighs risk. Limited safety data are available.
Q7: What are the potential drug interactions with Tulobuterol?
A: Significant interactions can occur with beta-blockers, other sympathomimetics, theophylline, diuretics, and certain antidepressants.
Q8: What monitoring parameters should be considered when prescribing Tulobuterol?
A: Pulmonary function, heart rate, blood pressure, and potassium levels should be monitored.
Q9: What is the difference between short-acting and long-acting beta2-agonists?
A: Short-acting beta2-agonists (SABAs) provide rapid but short-term relief of bronchospasm. Long-acting beta2-agonists (LABAs) provide prolonged bronchodilation, suitable for maintenance therapy. Tulobuterol is an LABA.
Q10: How long does the bronchodilator effect of Tulobuterol last?
A: With oral administration, the effect may last up to 12 hours. The transdermal patch provides continuous drug delivery for 24 hours.
