Usage
This combination is primarily indicated for the prophylaxis of asthma and wheeze in children and the treatment of nocturnal asthma. Ketotifen is an antihistamine with mast cell stabilizing properties, and theophylline is a bronchodilator. The combination’s pharmacological classifications are:
- Ketotifen: Antihistamine (H1 receptor antagonist), mast cell stabilizer.
- Theophylline: Bronchodilator (methylxanthine).
Theophylline works by relaxing bronchial smooth muscle, while Ketotifen prevents the release of histamine and other inflammatory mediators from mast cells. The combination aims to provide both bronchodilation and anti-inflammatory effects.
Alternate Names
There are no officially recognized alternate names for the combination product “Ketotifen + Theophylline.” However, the individual components are known by other names:
- Ketotifen: Ketotifen fumarate.
- Theophylline: Theophylline anhydrous, aminophylline (a theophylline ethylenediamine salt).
Brand names for combination products containing ketotifen and theophylline vary regionally and internationally. Some examples might include (note: these are hypothetical and might not be currently available): Asthofen, Bronkotif, Theotifen, etc. Always consult local pharmaceutical resources for available brand names.
How It Works
Ketotifen:
- Pharmacodynamics: Stabilizes mast cells, preventing the release of histamine and leukotrienes. Exhibits antihistaminic (H1 receptor antagonist) activity.
- Pharmacokinetics: Administered orally. Metabolized primarily in the liver. Excreted through urine and feces.
Theophylline:
- Pharmacodynamics: Relaxes bronchial smooth muscle (bronchodilation). Also has mild diuretic, cardiac stimulant, and CNS stimulant effects.
- Pharmacokinetics: Administered orally or intravenously. Metabolized in the liver by CYP450 enzymes (CYP1A2, CYP2E1, CYP3A4). Excreted primarily through urine.
Mode of Action:
- Ketotifen: Inhibits the release of inflammatory mediators like histamine and leukotrienes by stabilizing mast cell membranes. It binds to H1 receptors, blocking the effects of histamine.
- Theophylline: Inhibits phosphodiesterase enzymes, leading to increased intracellular cAMP, which relaxes bronchial smooth muscle. It also antagonizes adenosine receptors, which contribute to bronchodilation.
Dosage
Dosage information for the combined product Ketotifen + Theophylline is not readily available in the provided resources. However, dosing information for each drug is accessible. Therefore, below is dosage information for Ketotifen and Theophylline separately. When using a combination, refer to the specific product’s prescribing information.
Ketotifen
Standard Dosage
Adults: 1 mg twice daily.
Children (6 months to 3 years): 0.05 mg/kg twice daily.
Theophylline
Standard Dosage
Adults: Dosage must be individualized based on serum theophylline levels and clinical response. Target serum concentrations are typically 10-20 mcg/mL.
Children: Dosage is highly variable based on age and must be carefully determined and monitored.
Clinical Use Cases
Information regarding the combined use of Ketotifen and Theophylline in specific clinical settings such as intubation, surgical procedures, mechanical ventilation, ICU use, and emergency situations is limited. Theophylline is occasionally used in such contexts; however, newer agents with better safety profiles are generally preferred. In these situations, if used, theophylline dosing must be individualized, and careful monitoring is essential.
Side Effects
Ketotifen:
Common Side Effects: Drowsiness, dry mouth, weight gain.
Rare but Serious Side Effects: Severe allergic reactions.
Theophylline:
Common Side Effects: Nausea, vomiting, headache, insomnia, nervousness, irritability, dizziness, tachycardia.
Rare but Serious Side Effects: Seizures, cardiac arrhythmias.
Contraindications
Ketotifen: Hypersensitivity to ketotifen.
Theophylline: Hypersensitivity to theophylline or other xanthines. Active peptic ulcer disease. Uncontrolled seizure disorder.
Drug Interactions
Ketotifen: May potentiate the effects of sedatives and alcohol.
Theophylline: Numerous drug interactions; consult a comprehensive drug interaction resource. Some key interactions include:
- CYP1A2, CYP2E1, CYP3A4 inducers/inhibitors: Many medications can affect theophylline metabolism.
- Other xanthines (e.g., caffeine): Additive effects.
Pregnancy and Breastfeeding
Ketotifen: Use with caution during pregnancy and breastfeeding.
Theophylline: Can cross the placenta and is present in breast milk. Use with caution during pregnancy and breastfeeding.
Drug Profile Summary
Refer to the preceding sections for detailed information.
Popular Combinations
Theophylline may be combined with other bronchodilators or corticosteroids for asthma treatment. Ketotifen is often used as monotherapy. Their combination provides both bronchodilating and anti-inflammatory properties.
Precautions
Refer to the preceding sections for precautions relating to specific populations and conditions. Standard precautions such as screening for allergies and organ dysfunction apply.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Ketotifen + Theophylline?
A: The combined product’s dosage is not standardized. Refer to individual drug dosing information and consult the product’s prescribing information.
Q2: What are the common side effects of this combination?
A: Drowsiness, dry mouth, nausea, vomiting, headache, insomnia, and dizziness.
Q3: Are there any serious drug interactions I should be aware of?
A: Theophylline has numerous drug interactions. Consult a comprehensive resource for details.
Q4: Can this combination be used in pregnant or breastfeeding women?
A: Use with caution. Consult product prescribing information.
Q5: How does Ketotifen contribute to asthma management?
A: It prevents the release of inflammatory mediators from mast cells, reducing airway inflammation.
Q6: How does Theophylline work as a bronchodilator?
A: It relaxes bronchial smooth muscles, improving airflow.
Q7: What are the monitoring parameters for Theophylline?
A: Serum theophylline levels, heart rate, respiratory rate, clinical signs of toxicity.
Q8: Can Ketotifen be used alone for asthma?
A: Yes, Ketotifen is often used as monotherapy or in combination with other asthma medication. It is prescribed for asthma prophylaxis in children.
Q9: What are the signs of Theophylline toxicity?
A: Nausea, vomiting, seizures, cardiac arrhythmias.
