Product Overview
[Drug Name]
Generic Name: Theophylline Sustained-Release Tablets
Trade Name: Ruiyang Keqing Theophylline Sustained-Release Tablets 0.1g*30 Tablets
Pinyin Full Code: RuiYangKeQingChaJiaHuanShiPianO.1g*30Tablets
[Main Ingredients]
The main ingredient is anhydrous theophylline.
[Properties]
This product is a white tablet.
[Indications/Main Functions]
Indicated for the relief of wheezing symptoms in conditions such as bronchial asthma, asthmatic bronchitis, and obstructive pulmonary emphysema; it can also be used for asthma caused by cardiogenic emphysema.
[Specifications]
O.1g*30 Tablets
[Dosage and Administration]
For oral use. Do not crush or chew this product. 1. For adults and children over 12 years old, the starting dose is 0.1g-0.2g (1-2 tablets), twice daily, morning and evening, with 100ml of warm water. 2. The dosage should be adjusted based on the patient's condition and efficacy, but the daily dose should not exceed 0.9g (9 tablets), taken in two divided doses.
[Adverse Reactions]
Theophylline toxicity often occurs at serum concentrations of 15-20g/ml, especially at the beginning of treatment. Early symptoms include nausea, vomiting, irritability, and insomnia. When serum concentrations exceed 20g/ml, tachycardia and arrhythmias may occur. When serum theophylline concentrations exceed 40g/ml, fever, dehydration, and convulsions may occur. In severe cases, respiratory and cardiac arrest may occur, leading to death.
[Contraindications]
This product is contraindicated in patients with allergies to this product, active peptic ulcers, and uncontrolled seizure disorders.
[Drug Interactions]
1. Diltiazem and verapamil may interfere with theophylline metabolism in the liver. Concomitant use with this product may increase its blood concentration and toxicity.
2. Cimetidine may reduce the hepatic clearance of this product. Concomitant use may increase theophylline serum concentration and/or toxicity.
3. Certain antibacterial drugs, such as the macrolides erythromycin, roxithromycin, and clarithromycin, and the fluoroquinolones enoxacin, ciprofloxacin, ofloxacin, levofloxacin, clindamycin, and lincomycin, can reduce the clearance of theophylline and increase its plasma concentration. This is particularly true for erythromycin and enoxacin. When theophylline is used with these drugs, the dose should be appropriately reduced.
4. Phenobarbital, phenytoin, and rifampicin can induce hepatic enzymes, accelerating the hepatic clearance of theophylline. Theophylline also interferes with phenytoin absorption, decreasing the plasma concentrations of both. Therefore, the dose should be adjusted when used together.
5. Concomitant use with lithium salts can increase renal excretion of lithium, potentially affecting its effectiveness.
6. Concomitant use with mexiletine can reduce the clearance of theophylline and increase its plasma concentration, necessitating dose adjustment.
7. Concomitant use with caffeine or other xanthines can increase their effects and toxicity.
[Precautions]
1. Like other theophylline sustained-release preparations, this product is not suitable for patients with status asthmaticus or acute bronchitis spasms.
2. Serum theophylline concentrations should be monitored regularly to ensure maximum efficacy without the risk of excessive blood concentrations.
3. Patients with renal or hepatic insufficiency, patients over 55 years of age, especially men, and those with concomitant chronic lung disease, patients with heart failure of any cause, and patients with persistent fever. Patients taking certain medications and those with reduced theophylline clearance may experience significantly prolonged serum theophylline concentrations after discontinuation of concomitant medications. The dosage should be adjusted or the dosing interval extended as appropriate.
4. Theophylline preparations can cause arrhythmias and/or worsen existing arrhythmias; any changes in heart rate and/or rhythm should be monitored and investigated.
5. This product should be used with caution in patients with hypoxemia, hypertension, or a history of peptic ulcers.
6. Keep out of reach of children. Please read the instructions carefully and use as directed by your doctor.
[Pediatric Use]
Plasma clearance may be reduced in neonates, leading to increased serum concentrations. Caution is advised when using this product. The safety and effectiveness of this product in children under 12 years of age are uncertain. Children over 12 years of age should follow a physician's advice.
[Elderly Use]
Due to decreased plasma clearance and increased potential toxicity in the elderly, caution should be exercised in patients over 55 years of age.
[Overdose]
Unclear information is available.
[Pharmacology and Toxicology]
This product has a direct relaxant effect on airway smooth muscle. Its mechanism of action is complex. Previously, it was believed to be through inhibition of phosphodiesterase, which increases intracellular cAMP levels. Recent experiments suggest that the bronchodilator effect of theophylline is partially due to the release of endogenous epinephrine and norepinephrine. Furthermore, theophylline is a purine receptor blocker, counteracting the constrictive effects of adenine and other agonists on the airways. Theophylline can enhance diaphragmatic contractility, particularly when the diaphragm is weak, thus improving respiratory function.
