Doxiva

Approved Indications:

• Bronchial asthma: As maintenance treatment for chronic asthma in adults and children.
• Chronic Obstructive Pulmonary Disease (COPD): For the relief of bronchospasm in patients with COPD including chronic bronchitis and emphysema.

Clinically Accepted Off-label Uses:

• Acute exacerbations of asthma or COPD (as add-on): Occasionally used in combination with bronchodilators and corticosteroids for moderate to severe exacerbations.
• Allergic bronchitis: As a bronchodilator and anti-inflammatory adjunct.

রেজিস্টার্ড চিকিৎসকের নির্দেশনা অনুযায়ী ঔষধ সেবন করুন।

Adults:

• Usual dose: 400 mg twice daily.
• Dose may be increased up to 800 mg/day based on tolerance and clinical response.
• Modified-release tablets: Often administered once or twice daily depending on formulation.

Pediatrics:

• Syrup formulation:
• Children 6–12 years: 6 mg/kg twice daily.
• Children under 6 years: Use with caution; typically 6–12 mg/kg/day divided in two doses.

Elderly:

• Use lowest effective dose (200–400 mg/day).
• Monitor for signs of toxicity due to slower drug clearance.

Renal Impairment:

• No major adjustment usually needed, but monitor closely.

Hepatic Impairment:

• Use with caution; consider dose reduction.

Administration Notes:

• Administer with food to reduce GI irritation.
• Swallow sustained-release tablets whole; do not crush or chew.

রেজিস্টার্ড চিকিৎসকের নির্দেশনা অনুযায়ী ঔষধ সেবন করুন।

Doxophylline is a xanthine derivative structurally related to theophylline, but it lacks significant activity on adenosine receptors, which reduces its cardiovascular and CNS side effects. It primarily works by inhibiting the enzyme phosphodiesterase (PDE), especially PDE III and IV, leading to increased levels of cyclic AMP (cAMP) in bronchial smooth muscle cells. This results in bronchodilation and improved airflow. Doxophylline also exhibits anti-inflammatory properties by modulating leukocyte activity and cytokine production.

• Absorption: Rapid and well absorbed orally; food may slightly delay absorption but not the extent.
• Bioavailability: ~60–80%
• Peak Plasma Time: 1–2 hours (immediate release); 4–6 hours (sustained release)
• Distribution: Widely distributed; low protein binding (~40%)
• Metabolism: Hepatic via cytochrome P450 enzymes (notably CYP1A2 and CYP2E1)
• Half-life: ~7–8 hours in adults; may be prolonged in elderly or hepatic impairment
• Excretion: Primarily renal as inactive metabolites; <4% unchanged

• Pregnancy: Category C
• Animal studies show potential adverse effects; human data are limited.
• Use only if clearly needed; benefits must outweigh risks.
• Lactation:
• Unknown whether doxophylline is excreted in human milk.
• Caution is advised; monitor infants for signs of irritability or feeding issues.

• Primary Class: Xanthine bronchodilator
• Subclass: Methylxanthine derivative with selective PDE inhibition and reduced adenosine antagonism compared to theophylline

• Known hypersensitivity to doxophylline or other xanthines.
• Active peptic ulcer disease.
• Recent myocardial infarction or unstable cardiac conditions.
• History of seizures (relative contraindication due to CNS stimulation potential).

• Cardiac risk: Use with caution in patients with arrhythmias, heart failure, or hypertension.
• Seizure disorders: May lower seizure threshold; monitor closely.
• Hepatic impairment: Reduced clearance may increase risk of toxicity.
• Drug accumulation: Risk in elderly and those with hepatic/renal dysfunction.
• Avoid alcohol and other CNS stimulants due to additive CNS excitability.
• Therapeutic drug monitoring is generally not required, unlike with theophylline, but clinical monitoring is essential.

Common:

• Nausea, vomiting
• Headache
• Gastric discomfort
• Insomnia
• Palpitations

Less Common:

• Tremors
• Irritability
• Dizziness
• Increased urination

Serious/Rare:

• Seizures (especially in overdose)
• Cardiac arrhythmias
• Allergic reactions
• Hepatotoxicity (rare)

• Erythromycin, ciprofloxacin: May increase plasma levels of doxophylline via CYP inhibition.
• Beta-agonists (e.g., salbutamol): Additive bronchodilation; monitor for hypokalemia and cardiac effects.
• Phenytoin, carbamazepine: May decrease doxophylline levels via hepatic enzyme induction.
• Caffeine: Additive CNS stimulation.
• Alcohol: Increases the risk of gastrointestinal irritation and CNS effects.

• Doxophylline is recognized as a safer alternative to theophylline due to a better safety profile and fewer drug interactions.
• Included in several treatment algorithms in low-resource settings where inhaled corticosteroids may be less accessible.
• Not routinely used in high-income countries due to preference for inhaled therapies, but still widely prescribed in Asia, Eastern Europe, and parts of Latin America.

• Store at 20°C to 25°C (68°F to 77°F)
• Protect from moisture and direct sunlight.
• Keep container tightly closed.
• Do not freeze liquid or syrup formulations.
• Keep out of reach of children.