Usage
- Etofylline is prescribed for the treatment of respiratory conditions like asthma, chronic obstructive pulmonary disease (COPD), chronic bronchitis, and emphysema. It can also be used in premature infants who experience apnea (cessation of breathing).
- Pharmacological classification: Bronchodilator, specifically a xanthine derivative.
- Mechanism of Action: Etofylline relaxes the smooth muscles of the airways and pulmonary blood vessels, widening them and making breathing easier. It achieves this primarily by inhibiting phosphodiesterase enzymes, which leads to increased intracellular cyclic AMP levels and subsequent smooth muscle relaxation.
Alternate Names
- Doxofylline (common international non-proprietary name)
How It Works
- Pharmacodynamics: Etofylline’s primary effect is bronchodilation. It also has some anti-inflammatory properties.
- Pharmacokinetics:
- Absorption: Etofylline is well-absorbed after oral administration.
- Metabolism: Etofylline is primarily metabolized in the liver by CYP450 enzymes, particularly CYP1A2.
- Elimination: Etofylline is mainly eliminated via the kidneys.
- Mode of Action: Inhibits phosphodiesterase enzymes, leading to increased intracellular cyclic AMP. This results in smooth muscle relaxation in the airways and pulmonary vessels.
- Receptor Binding/Enzyme Inhibition: Inhibits phosphodiesterase enzymes.
- Elimination Pathways: Primarily renal excretion, with some hepatic metabolism by CYP1A2.
Dosage
Standard Dosage
Adults:
- Initial dose: 300-400 mg/day orally, in divided doses.
- Maintenance dose: 400-600 mg/day, adjustable based on clinical response and serum theophylline levels (if applicable).
Children:
- Dosage is based on body weight and age.
- Infants (under 1 year): 2-3 mg/kg every 6-8 hours.
- Children (1-12 years): 4-6 mg/kg every 6-8 hours.
- Adolescents (12+ years): Similar to adult dose, adjusted as needed.
Special Cases:
- Elderly Patients: Lower starting doses are recommended, with careful titration based on response and potential for drug interactions.
- Patients with Renal Impairment: Dose reduction may be necessary.
- Patients with Hepatic Dysfunction: Dose adjustment is required due to impaired metabolism.
- Patients with Comorbid Conditions: Consider individual patient factors and potential for drug interactions.
Clinical Use Cases
The provided sources do not mention specific dosage recommendations for these clinical scenarios for etofylline in isolation. Dosages would depend on the specific clinical context and would likely follow the standard dosage guidelines.
Dosage Adjustments
- Adjust dose based on patient-specific factors, including renal/hepatic dysfunction and other comorbid conditions. Therapeutic drug monitoring may be useful in some cases.
Side Effects
Common Side Effects:
- Nausea
- Vomiting
- Headache
- Dizziness
- Stomach pain
- Diarrhea
- Restlessness
- Nervousness
- Insomnia
Rare but Serious Side Effects:
- Seizures
- Irregular heartbeat
- Fainting
- Confusion
Long-Term Effects:
Data on long-term effects are limited.
Adverse Drug Reactions (ADR):
- Severe allergic reactions (rare)
- Cardiac arrhythmias (especially with concomitant use of other drugs affecting cardiac rhythm)
Contraindications
- Hypersensitivity to etofylline or other xanthine derivatives
- Severe liver disease
- Severe kidney disease
- Certain heart conditions (e.g., arrhythmias, coronary insufficiency)
Drug Interactions
- CYP450 interactions: Etofylline is metabolized by CYP1A2. Inhibitors (e.g., cimetidine, fluoroquinolones) can increase etofylline levels, while inducers (e.g., rifampicin, barbiturates) can decrease levels.
- Other clinically significant interactions:
- Antidepressants (e.g., clomipramine, amitriptyline)
- Anti-retroviral drugs (e.g., ritonavir)
- Antibiotics (e.g., erythromycin, ciprofloxacin)
- Antifungals (e.g., fluconazole)
- Anti-tuberculosis drugs (e.g., isoniazid, rifampicin)
- Diuretics
- Oral contraceptives
- Other xanthines (e.g., theophylline, caffeine)
- Beta-blockers
- Sympathomimetics
- Anesthetic agents
- Pancuronium bromide
- Anticonvulsants
- Sulfinpyrazone
- Quinolone antibiotics
- Ephedrine
Pregnancy and Breastfeeding
- Limited safety information is available regarding etofylline use during pregnancy and breastfeeding. Consult a doctor before use.
- Etofylline is excreted in breast milk.
Drug Profile Summary
- Mechanism of Action: Bronchodilation via phosphodiesterase inhibition.
- Side Effects: Nausea, vomiting, headache, dizziness, stomach pain, diarrhea, restlessness, nervousness, insomnia. Serious side effects include seizures and irregular heartbeat.
- Contraindications: Hypersensitivity, severe liver/kidney disease, certain heart conditions.
- Drug Interactions: Numerous drug interactions; see detailed list above.
- Pregnancy & Breastfeeding: Consult a doctor before use. Excreted in breast milk.
- Dosage: Varies by age, weight, and condition; see detailed dosage guidelines above.
- Monitoring Parameters: Serum theophylline levels (if applicable), respiratory function, cardiovascular status.
Popular Combinations
- Etofylline is sometimes combined with other bronchodilators, such as salbutamol, for synergistic effects.
- Combinations with theophylline are also used, although careful dosage adjustment is necessary to avoid toxicity.
Precautions
- General Precautions: Evaluate patients for pre-existing conditions like heart, liver, or kidney disease, peptic ulcer, hyperthyroidism, and seizure disorders. Screen for allergies.
- Specific Populations: See “Dosage - Special Cases” and “Pregnancy and Breastfeeding”.
- Lifestyle Considerations: Advise patients to limit caffeine intake, avoid alcohol (as it can potentiate side effects), and discuss potential effects on driving/operating machinery.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Etofylline?
A: See detailed dosage guidelines above, as it varies based on age, weight, and indication.
Q2: What are the common side effects of Etofylline?
A: Common side effects include nausea, vomiting, headache, dizziness, stomach upset, diarrhea, restlessness, nervousness, and insomnia.
Q3: Is Etofylline safe to use during pregnancy?
A: Limited safety information is available. Consult a doctor before use during pregnancy.
Q4: Can Etofylline be used in children?
A: Yes, but the dosage needs to be adjusted based on age and body weight. See pediatric dosage guidelines above.
Q5: Does Etofylline interact with other medications?
A: Yes, Etofylline has numerous potential drug interactions. See the detailed list in the “Drug Interactions” section.
Q6: What is the mechanism of action of Etofylline?
A: Etofylline inhibits phosphodiesterase enzymes, leading to bronchodilation.
Q7: What are the contraindications for Etofylline use?
A: Contraindications include hypersensitivity, severe liver or kidney disease, and certain heart conditions.
Q8: How should Etofylline be administered?
A: Etofylline is typically administered orally as tablets or syrup. It is also available as an injectable solution for intravenous administration.
Q9: What should patients be advised regarding lifestyle while taking Etofylline?
A: Patients should be advised to limit or avoid caffeine intake, limit alcohol consumption, and exercise caution when driving or operating machinery. They should also be advised to maintain adequate hydration and a balanced diet.
