Consists of Etophylline, Theophylline
Consists of Etophylline, Theophylline
Theophylline (Meriphyllin) (theophylline anhydrous capsule) ®, like other extended-release theophylline products, is intended for patients with relatively continuous or recurring symptoms who have a need to maintain therapeutic serum levels of theophylline. It is not intended for patients experiencing an acute episode of bronchospasm (associated with asthma, chronic bronchitis, or emphysema). Such patients require rapid relief of symptoms and should be treated with an immediate-release or intravenous theophylline preparation (or other bronchodilators) and not with extended-release products.
Patients who metabolize theophylline at a normal or slow rate are reasonable candidates for once-daily dosing with Theophylline (Meriphyllin) (theophylline anhydrous capsule) ®. Patients who metabolize theophylline rapidly (e.g., the young, smokers, and some nonsmoking adults) and who have symptoms repeatedly at the end of a dosing interval, will require either increased doses given once a day or preferably, are likely to be better controlled by a schedule of twice-daily dosing. Those patients who require increased daily doses are more likely to experience relatively wide peak-trough differences and may be candidates for twice-a-day dosing with Theophylline (Meriphyllin) (theophylline anhydrous capsule) ®.
Patients should be instructed to take this medication each morning at approximately the same time and not to exceed the prescribed dose.
Recent studies suggest that dosing of extended-release theophylline products at night (after the evening meal) results in serum concentrations of theophylline which are not identical to those recorded during waking hours and may be characterized by early trough and delayed peak levels. This appears to occur whether the drug is given as an immediate-release, extended-release, or intravenous product. To avoid this phenomenon when two doses per day are prescribed, it is recommended that the second dose be given 10 to 12 hours after the morning dose and before the evening meal.
Food and posture, along with changes associated with circadian rhythm, may influence the rate of absorption and/or clearance rates of theophylline from extended-release dosage forms administered at night. The exact relationship of these and other factors to nighttime serum concentrations and the clinical significance of such findings require additional study. Therefore, it is not recommended that
Theophylline (Meriphyllin) (theophylline anhydrous capsule) ® (when used as a once-a-day product) be administered at night.
Patients who require a relatively high dose of theophylline (i.e., a dose equal to or greater than 900 mg or 13 mg/kg, whichever is less) should not take Theophylline (Meriphyllin) (theophylline anhydrous capsule) ® less than 1 hour before a high-fat-content meal since this may result in a significant increase in peak serum level and in the extent of absorption of theophylline as compared to administration in the fasted state.
The steady-state peak serum theophylline concentration is a function of the dose, the dosing interval, and the rate of theophylline absorption and clearance in the individual patient. Because of marked individual differences in the rate of theophylline clearance, the dose required to achieve a peak serum theophylline concentration in the 10-20 mcg/mL range varies fourfold among otherwise similar patients in the absence of factors known to alter theophylline clearance (e.g., 400-1600 mg/day in adults < 60 years old and 10-36 mg/kg/day in children 1-9 years old). For a given population there is no single theophylline dose that will provide both safe and effective serum concentrations for all patients. Administration of the median theophylline dose required to achieve a therapeutic serum theophylline concentration in a given population may result in either sub-therapeutic or potentially toxic serum theophylline concentrations in individual patients. For example, at a dose of 900 mg/day in adults < 60 years or 22 mg/kg/day in children 1-9 years, the steady-state peak serum theophylline concentration will be < 10 mcg/mL in about 30% of patients, 10-20 mcg/mL in about 50% and 20-30 mcg/mL in about 20% of patients. The dose of theophylline must be individualized on the basis of peak serum theophylline concentration measurements in order to achieve a dose that will provide maximum potential benefit with minimal risk of adverse effects.
Transient caffeine-like adverse effects and excessive serum concentrations in slow metabolizers can be avoided in most patients by starting with a sufficiently low dose and slowly increasing the dose, if judged to be clinically indicated, in small increments. Dose increases should only be made if the previous dosage is well tolerated and at intervals of no less than 3 days to allow serum theophylline concentrations to reach the new steady state. Dosage adjustment should be guided by serum theophylline concentration measurement. Health care providers should instruct patients and care givers to discontinue any dosage that causes adverse effects, to withhold the medication until these symptoms are gone and to then resume therapy at a lower, previously tolerated dosage.
If the patient's symptoms are well controlled, there are no apparent adverse effects, and no intervening factors that might alter dosage requirements, serum theophylline concentrations should be monitored at 6 month intervals for rapidly growing children and at yearly intervals for all others. In acutely ill patients, serum theophylline concentrations should be monitored at frequent intervals, e.g., every 24 hours.
Theophylline distributes poorly into body fat, therefore, mg/kg dose should be calculated on the basis of ideal body weight. Table V contains theophylline dosing titration schema recommended for patients in various age groups and clinical circumstances. Table VI contains recommendations for theophylline dosage adjustment based upon serum theophylline concentrations. Application of these general dosing recommendations to individual patients must take into account the unique clinical characteristics of each patient. In general, these recommendations should serve as the upper limit for dosage adjustments in order to decrease the risk of potentially serious adverse events associated with unexpected large increases in serum theophylline concentration.
Table V. Dosing initiation and titration (as anhydrous theophylline).*
|A. Children (12-15 years) and adults (16-60 years) without risk factors for impaired clearance.|
|Titration Step||Children < 45 kg||Children > 45 kg and adults|
|1. Starting Dosage||12-14 mg/kg/day up to a maximum of 300 mg/day divided Q 24 hrs*||300-400 mg/day Dose reduction and/or serum theophylline concentration measurement is indicated whenever adverse effects are present, physiologic abnormalities that can reduce theophylline clearance occur (e.g., sustained fever), or a drug that interacts with theophylline is added or discontinued.|
Theophylline (Meriphyllin) (theophylline anhydrous capsule) ® (theophylline anhydrous) is supplied in extended-release capsules containing 100, 200, 300 or 400 mg of anhydrous theophylline.
Theophylline (Meriphyllin) (theophylline anhydrous capsule) ® 100 mg capsules are yellow-orange and clear, with markings Theophylline (Meriphyllin) (theophylline anhydrous capsule), 100 mg, ucb, and 2832, supplied as:
|50474-100-01||bottle of 100|
|Theophylline (Meriphyllin)® 200 mg capsules are red-orange and clear, with markings Theophylline (Meriphyllin), 200 mg, ucb, and 2842, supplied as:|
|50474-200-01||bottle of 100|
|50474-200-50||bottle of 500|
|Theophylline (Meriphyllin)® 300 mg capsules are red and clear, with markings Theophylline (Meriphyllin), 300 mg, ucb, and 2852, supplied as:|
|50474-300-01 50474-300-50||bottle of 100 bottle of 500|
|Theophylline (Meriphyllin)® 400 mg capsules are pink and clear, with markings Theophylline (Meriphyllin), 400 mg, ucb, and 2902, supplied as:|
|50474-400-01||bottle of 100|
Store below 77 °F (25 °C).
FOR MEDICAL INFORMATION Contact: Medical Affairs Department Phone: (800) 477-7877, Fax: (770) 970-8859. Manufactured for: UCB Pharma, Inc. Smyrna, GA 30080. by Pfizer Pharmaceuticals LLC Caguas, PR 00725. 04/2005.
Sometimes it is not safe to use certain drugs at the same time. Some medicines can affect how theophylline works, which could make it less effective or cause side effects. Theophylline could also affect how other medicines work, making them less effective or causing side effects.
Many drugs can interact with theophylline and not all possible interactions are listed in this medication guide. Tell your doctor about all medications you use, start using, or stop using during your treatment with theophylline, especially:
interferon alfa (Intron A, Rebetron, Alferon, Infergen, Pegasys, PegIntron, Sylatron);
lithium (Eskalith, Lithobid);
an antibiotic, or medication to treat tuberculosis;
heart or blood pressure medication, such as propranolol (Inderal, InnoPran);
heart rhythm medication such as mexiletine (Mexitil) or propafenone (Rythmol);
medication to treat gout or kidney stones;
a sedative such as Valium; or
This list is not complete and many other drugs can interact with theophylline. This includes prescription, over-the-counter, vitamin, and herbal products. Keep a list of all your medicines and show it to any healthcare provider who treats you.
Theophylline interacts with a wide variety of drugs. The interaction may be pharmacodynamic, i.e., alterations in the therapeutic response to theophylline or another drug or occurrence of adverse effects without a change in serum theophylline concentration. More frequently, however, the interaction is pharmacokinetic, i.e., the rate of theophylline clearance is altered by another drug resulting in increased or decreased serum theophylline concentrations. Theophylline only rarely alters the pharmacokinetics of other drugs.
The drugs listed in Table II have the potential to produce clinically significant pharmacodynamic or pharmacokinetic interactions with theophylline. The information in the “Effect ” column of Table II assumes that the interacting drug is being added to a steady-state theophylline regimen. If theophylline is being initiated in a patient who is already taking a drug that inhibits theophylline clearance (e.g., cimetidine, erythromycin), the dose of theophylline required to achieve a therapeutic serum theophylline concentration will be smaller. Conversely, if theophylline is being initiated in a patient who is already taking a drug that enhances theophylline clearance (e.g., rifampin), the dose of theophylline required to achieve a therapeutic serum theophylline concentration will be larger. Discontinuation of a concomitant drug that increases theophylline clearance will result in accumulation of theophylline to potentially toxic levels, unless the theophylline dose is appropriately reduced. Discontinuation of a concomitant drug that inhibits theophylline clearance will result in decreased serum theophylline concentrations, unless the theophylline dose is appropriately increased.
The drugs listed in Table III have either been documented not to interact with theophylline or do not produce a clinically significant interaction (i.e., < 15% change in theophylline clearance).
The listing of drugs in Table II is current as of June 2004. The listing of drugs in Table III is current as of January 2, 1996. New interactions are continuously being reported for theophylline, especially with new chemical entities. The healthcare professional should not assume that a drug does not interact with theophylline if it is not listed in Table II. Before addition of a newly available drug in a patient receiving theophylline, the package insert of the new drug and/or the medical literature should be consulted to determine if an interaction between the new drug and theophylline has been reported.
Table II. Clinically significant drug interactions with theophylline*.
|Drug||Type of Interaction||Effect**|
|Adenosine||Theophylline blocks adenosine receptors.||Higher doses of adenosine may be required to achieve desired effect.|
|Alcohol||A single large dose of alcohol (3 mL/kg of whiskey) decreases theophylline clearance for up to 24 hours.||30% increase|
|Allopurinol||Decreases theophylline clearance at allopurinol doses ≥ 600 mg/day.||25% increase|
|Aminoglutethimide||Increases theophylline clearance by induction of microsomal enzyme activity.||25% decrease|
|Carbamazepine||Similar to aminoglutethimide.||30% decrease|
|Cimetidine||Decreases theophylline clearance by inhibiting cytochrome P450 1A2.||70% increase|
|Ciprofloxacin||Similar to cimetidine.||40% increase|
|Clarithromycin||Similar to erythromycin.||25% increase|
|Diazepam||Benzodiazepines increase CNS concentrations of adenosine, a potent CNS depressant, while theophylline blocks adenosine receptors.||Larger diazepam doses may be required to produce desired level of sedation. Discontinuation of theophylline without reduction of diazepam dose may result in respiratory depression.|
|Disulfiram||Decreases theophylline clearance by inhibiting hydroxylation and demethylation.||50% increase|
|Enoxacin||Similar to cimetidine.||300% increase|
|Ephedrine||Synergistic CNS effects.||Increased frequency of nausea, nervousness, and insomnia.|
|Erythromycin||Erythromycin metabolite decreases theophylline clearance by inhibiting cytochrome P450 3A3.||35% increase. Erythromycin steady-state serum concentrations decrease by a similar amount.|
|Estrogen||Estrogen containing oral contraceptives decrease theophylline clearance in a dose-dependent fashion. The effect of progesterone on theophylline clearance is unknown.||30% increase|
|Flurazepam||Similar to diazepam.||Similar to diazepam.|
|Fluvoxamine||Similar to cimetidine.||Similar to cimetidine|
|Halothane||Halothane sensitizes the myocardium to catecholamines, theophylline increases release of endogenous catecholamines.||Increased risk of ventricular arrhythmias.|
|Interferon, human recombinant alpha-A||Decreases theophylline clearance.||100% increase|
|Isoproterenol (IV)||Increases theophylline clearance.||20% decrease|
|Ketamine||Pharmacologic.||May lower theophylline seizure threshold.|
|Lithium||Theophylline increases renal lithium clearance.||Lithium dose required to achieve a therapeutic serum concentration increased an average of 60%.|
|Lorazepam||Similar to diazepam.||Similar to diazepam.|
|Methotrexate (MTX)||Decreases theophylline clearance.||20% increase after low dose MTX, higher dose MTX may have a greater effect.|
|Mexiletine||Similar to disulfiram.||80% increase|
|Midazolam||Similar to diazepam.||Similar to diazepam.|
|Moricizine||Increases theophylline clearance.||25% decrease|
|Pancuronium||Theophylline may antagonize non-depolarizing neuromuscular blocking effects, possibly due to phosphodiesterase inhibition.||Larger dose of pancuronium may be required to achieve neuromuscular blockade|
|Pentoxifylline||Decreases theophylline clearance.||30% increase|
|Phenobarbital (PB)||Similar to aminoglutethimide.||25% decrease after two weeks of concurrent PB.|
|Phenytoin||Phenytoin increases theophylline clearance by increasing microsomal enzyme activity. Theophylline decreases phenytoin absorption.||Serum theophylline and phenytoin concentrations decrease about 40%.|
|Propafenone||Decreases theophylline clearance and pharmacologic interaction.||40% increase. Beta blockingeffect may decrease efficacy oftheophylline|
|Rifampin||Increases theophylline clearance by increasing cytochrome P450 1A2 and 3A3 activity.||20-40% decrease|
|St. John's Wort (Hypericum Perforatum)||Decrease in theophylline plasma concentrations.||Higher doses of theophylline may be required to achieve desired effect. Stopping St. John's Wort may result in theophylline toxicity.|
|Sulfinpyrazone||Increases theophylline clearance by increasing demethylation and hydroxylation. Decreases renal clearance of theophylline.||20% decrease|
|Tacrine||Similar to cimetidine, also increases renal clearance of theophylline.||90% increase|
|Thiabendazole||Decreases theophylline clearance.||190% increase|
|Ticlopidine||Decreases theophylline clearance.||60% increase|
|Troleandomycin||Similar to erythromycin.||33-100% increase depending on troleandomycin dose.|
|Verapamil||Similar to disulfiram.||20% increase|
|* Refer to PRECAUTIONS, Drug Interactions for further information regarding table. |
** Average effect on steady state theophylline concentration or other clinical effect for pharmacologic interactions. Individual patients may experience larger changes in serum theophylline concentration than the value listed.
Table III. Drugs that have been documented not to interact with theophylline or drugs that produce no clinically significant interaction with theophylline.*
|albuterol, systemic and inhaled||finasteride||norfloxacin|
|ampicillin, with or without sulbactam||isoniazid||prednisone, prednisolone|
|caffeine, dietary ingestion||lomefloxacin||sorbitol|
|cefaclor||mebendazole||(purgative doses do not inhibit theophylline absorption)|
|co-trimoxazole (trimethoprim and sulfamethoxazole)||medroxyprogesterone|
|* Refer to PRECAUTIONS: DRUG INTERACTIONS for information regarding table.|
Taking Theophylline (Meriphyllin) (theophylline anhydrous capsule) ® less than one hour before a high-fat-content meal, such as 8 oz whole milk, 2 fried eggs, 2 bacon strips, 2 oz hashed brown potatoes, and 2 slices of buttered toast (about 985 calories, including approximately 71 g of fat) may result in a significant increase in peak serum level and in the extent of absorption of theophylline as compared to administration in the fasted state. In some cases (especially with doses of 900 mg or more taken less than one hour before a high-fat-content meal) serum theophylline levels may exceed the 20 mcg/mL level, above which theophylline toxicity is more likely to occur.
Most serum theophylline assays in clinical use are immunoassays which are specific for theophylline. Other xanthines such as caffeine, dyphylline, and pentoxifylline are not detected by these assays. Some drugs (e.g., cefazolin, cephalothin), however, may interfere with certain HPLC techniques. Caffeine and xanthine metabolites in neonates or patients with renal dysfunction may cause the reading from some dry reagent office methods to be higher than the actual serum theophylline concentration.
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Information checked by Dr. Sachin Kumar, MD Pharmacology