Theo-24 theophylline anhydrous 100 mg Capsule, Extended Release, 100-count
🆔 Identity & classification
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🏷️ RxNorm drug class
This medicine belongs to the Methylxanthine class.
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🏭 Manufacturer & labeler
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🩺 Clinical
Theophylline is used to prevent and treat wheezing, shortness of breath, and chest tightness caused by asthma, chronic bronchitis, emphysema, and other lung diseases. It relaxes and opens air passages in the lungs, making it easier to breathe.
Read the full MedlinePlus article ↗- Theophylline is a long-term controller medicine for chronic asthma, emphysema, and chronic bronchitis. It works by relaxing the muscles around your airways so they stay more open,...
- What exactly is theophylline supposed to do for me?
- Yes, timing matters. If you're on Theo-24 extended-release capsules once a day, take it every morning at roughly the same time — taking it at night is not recommended because your...
- How should I take my theophylline, and does it matter when I take it?
Patient education
Supplement & herbal interactions
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Ask a licensed pharmacist directly — free, answered by our team.
💊 What it looks like
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🧪 Inactive Ingredients / Excipients
Inactive ingredients, also called excipients, are components of the drug product other than the active ingredient. They may include fillers, dyes, coatings, preservatives, flavors, or other formulation ingredients.
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IACT rows and label-wide narrative are kept separate; availability and product-level specificity depend on the submitted label.Inactive ingredient FAQ
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💲 Pricing
A drug doesn't have one price. Each row is a different public payment system, and none is what you'd pay at the counter — that depends on your insurance. The ⓘ on each row explains what it measures.
| Price system | Per ea | Per package |
|---|---|---|
| Retail pharmacies payNADAC · weekly | $3.816 | $381.61 / 100 capsules |
| Medicaid paysCMS SDUD · 12 mo | $3.86 | $385.58 / 100 capsules |
| Medicare drug plans payPart D · Q2 2026 | $3.74 | $374.00 / 100 capsules |
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🔁 Therapeutic equivalents
| Product | Labeler | Pack | NADAC/unit | TE | Status | Price vs. this |
|---|---|---|---|---|---|---|
| Theo-24 100 mgthis 52244-0100-10 | ENDO | 100 capsules | $3.816 | — | Availability likely | — |
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⏳ Availability & generic status
This product is an FDA-approved generic. Other versions of the same drug are listed under Therapeutic equivalents, least expensive first.
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🗺️ Medicaid utilization & spend
📊 Medicare Part D spend CMS · PART D · 2026 (Q1)
🔬 Reported adverse events (FAERS)
Top reported reactions
Age at onset
Reporter sex
Serious outcomes
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📦 Packaging — all sizes for this product
| Package NDC | Description | Marketing start | Status |
|---|---|---|---|
| 52244-0100-10 You're viewing this | 100 CAPSULE, EXTENDED RELEASE in 1 BOTTLE (52244-100-10) | 2014-08-25 | Active |
📄 Full prescribing information FDA SPL
🎯 Indications and Usage ▾
INDICATIONS AND USAGE Theophylline is indicated for the treatment of the symptoms and reversible airflow obstruction associated with chronic asthma and other chronic lung diseases, e.g., emphysema and chronic bronchitis.
⏱️ Dosage and Administration ▾
DOSAGE AND ADMINISTRATION General Considerations: Theo-24, 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 Theo-24. 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 Theo-24.
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 Theo-24 (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 Theo-24 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 (see PRECAUTIONS, Drug/Food Interactions ).
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…
⛔ Contraindications ▾
CONTRAINDICATIONS Theo-24 is contraindicated in patients with a history of hypersensitivity to theophylline or other components in the product.
⚠️ Warnings ▾
WARNINGS Concurrent Illness: Theophylline should be used with extreme caution in patients with the following clinical conditions due to the increased risk of exacerbation of the concurrent condition: Active peptic ulcer disease Seizure disorders Cardiac arrhythmias (not including bradyarrhythmias) Conditions That Reduce Theophylline Clearance There are several readily identifiable causes of reduced theophylline clearance. If the total daily dose is not appropriately reduced in the presence of these risk factors, severe and potentially fatal theophylline toxicity can occur.
Careful consideration must be given to the benefits and risks of theophylline use and the need for more intensive monitoring of serum theophylline concentrations in patients with the following risk factors: Age Neonates (term and premature) Children <1 year Elderly (>60 years) Concurrent Diseases Acute pulmonary edema Congestive heart failure Cor-pulmonale Fever; ≥102°F for 24 hours or more; or lesser temperature elevations for longer periods Hypothyroidism Liver disease; cirrhosis, acute hepatitis Reduced renal function in infants <3 months of age Sepsis with multi-organ failure Shock Cessation of Smoking Drug Interactions Adding a drug that inhibits theophylline metabolism (e.g., cimetidine, erythromycin, tacrine) or stopping a concurrently administered drug that enhances theophylline metabolism (e.g., carbamazepine, rifampin) (see PRECAUTIONS, Drug Interactions , Table II).
When Signs or Symptoms of Theophylline Toxicity Are Present: Whenever a patient receiving theophylline develops nausea or vomiting, particularly repetitive vomiting, or other signs or symptoms consistent with theophylline toxicity (even if another cause may be suspected), additional doses of theophylline should be withheld and a serum theophylline concentration measured immediately. Patients should be instructed not to continue any dosage that causes adverse effects and to withhold subsequent doses until the symptoms have resolved, at which time the healthcare professional may instruct the patient to resume the drug at a lower dosage (see DOSAGE AND ADMINISTRATION , Dosing Guidelines, Table VI).
Dosage Increases: Increases in the dose of theophylline should not be made in response to an acute exacerbation of symptoms of chronic lung disease since theophylline provides little added benefit to inhaled beta 2 -selective agonists and systemically administered corticosteroids in this circumstance and increases the risk of adverse effects. A peak steady-state serum theophylline concentration should be measured before increasing the dose in response to persistent chronic symptoms to ascertain whether an increase in dose is safe.
Before increasing the theophylline dose on the basis of a low serum concentration, the healthcare professional should consider whether the blood sample was obtained at an appropriate time in relationship to the dose and whether the patient has adhered to the prescribed regimen (see PRECAUTIONS, Laboratory Tests ). As the rate of theophylline clearance may be dose-dependent (i.e., steady-state serum concentrations may increase disproportionately to the increase in dose), an increase in dose based upon a sub-therapeutic serum concentration measurement should be conservative.
In general, limiting dose increases to about 25% of the previous total daily dose will reduce the risk of unintended excessive increases in serum theophylline concentration (see DOSAGE AND ADMINISTRATION , Table VI).
🤒 Adverse Reactions ▾
ADVERSE REACTIONS Adverse reactions associated with theophylline are generally mild when peak serum theophylline concentrations are <20 mcg/mL and mainly consist of transient caffeine-like adverse effects such as nausea, vomiting, headache, and insomnia. When peak serum theophylline concentrations exceed 20 mcg/mL, however, theophylline produces a wide range of adverse reactions including persistent vomiting, cardiac arrhythmias, and intractable seizures which can be lethal (see OVERDOSAGE ). The transient caffeine-like adverse reactions occur in about 50% of patients when theophylline therapy is initiated at doses higher than recommended initial doses (e.g., >300 mg/day in adults and >12 mg/kg/day in children beyond 1 year of age).
During the initiation of theophylline therapy, caffeine-like adverse effects may transiently alter patient behavior, especially in school age children, but this response rarely persists. Initiation of theophylline therapy at a low dose with subsequent slow titration to a predetermined age-related maximum dose will significantly reduce the frequency of these transient adverse effects (see DOSAGE AND ADMINISTRATION , Table V). In a small percentage of patients (<3% of children and <10% of adults) the caffeine-like adverse effects persist during maintenance therapy, even at peak serum theophylline concentrations within the therapeutic range (i.e., 10 - 20 mcg/mL).
Dosage reduction may alleviate the caffeine-like adverse effects in these patients, however, persistent adverse effects should result in a reevaluation of the need for continued theophylline therapy and the potential therapeutic benefit of alternative treatment. Other adverse reactions that have been reported at serum theophylline concentrations <20 mcg/mL include diarrhea, irritability, restlessness, fine skeletal muscle tremors, and transient diuresis. In patients with hypoxia secondary to COPD, multifocal atrial tachycardia and flutter have been reported at serum theophylline concentrations ≥15 mcg/mL.
There have been a few isolated reports of seizures at serum theophylline concentrations <20 mcg/mL in patients with an underlying neurological disease or in elderly patients. The occurrence of seizures in elderly patients with serum theophylline concentrations <20 mcg/mL may be secondary to decreased protein binding resulting in a larger proportion of the total serum theophylline concentration in the pharmacologically active unbound form. The clinical characteristics of the seizures reported in patients with serum theophylline concentrations <20 mcg/mL have generally been milder than seizures associated with excessive serum theophylline concentrations resulting from an overdose (i.e., they have generally been transient, often stopped without anticonvulsant therapy, and did not result in neurological residua).
Table IV. Manifestations of theophylline toxicity.* Percentage of patients reported with sign or symptom Acute Overdose (Large Single Ingestion) Chronic Overdosage (Multiple Excessive Doses) Sign/Symptom Study 1 (n=157) Study 2 (n=14) Study 1 (n=92) Study 2 (n=102) * These data are derived from two studies in patients with serum theophylline concentrations >30 mcg/mL. In the first study (Study #1—Shanon, Ann Intern Med 1993;119:1161-67), data were prospectively collected from 249 consecutive cases of theophylline toxicity referred to a regional poison center for consultation.
In the second study (Study #2—Sessler, Am J Med 1990;88:567-76), data were retrospectively collected from 116 cases with serum theophylline concentrations >30 mcg/mL among 6000 blood samples obtained for measurement of serum theophylline concentrations in three emergency departments. Differences in the incidence of manifestations of theophylline toxicity between the two studies may reflect sample selection as a result of study design (e.g., in Study #1, 48% of the patients had acute intoxications versus only 10 in Study #2) and different methods of reporting resul…
🔄 Drug Interactions ▾
Drug Interactions: Drug/Drug Interactions 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† * 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. 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 depressi…
🤰 Pregnancy ▾
Pregnancy: CATEGORY C: In studies in which pregnant mice, rats and rabbits were dosed during the period of organogenesis, theophylline produced teratogenic effects. In studies with mice, a single intraperitoneal dose at and above 100 mg/kg (approximately equal to the maximum recommended oral dose for adults on a mg/m 2 basis) during organogenesis produced cleft palate and digital abnormalities. Micromelia, micrognathia, clubfoot, subcutaneous hematoma, open eyelids, and embryolethality were observed at doses that are approximately 2 times the maximum recommended oral dose for adults on a mg/m 2 basis.
In a study with rats dosed from conception through organogenesis, an oral dose of 150 mg/kg/day (approximately 2 times the maximum recommended oral dose for adults on a mg/m 2 basis) produced digital abnormalities. Embryolethality was observed with a subcutaneous dose of 200 mg/kg/day (approximately 4 times the maximum recommended oral dose for adults on a mg/m 2 basis). In a study in which pregnant rabbits were dosed throughout organogenesis, an intravenous dose of 60 mg/kg/day (approximately 2 times the maximum recommended oral dose for adults on a mg/m 2 basis), which caused the death of one doe and clinical signs in others, produced cleft palate and was embryolethal.
Doses at and above 15 mg/kg/day (less than the maximum recommended oral dose for adults on a mg/m 2 basis) increased the incidence of skeletal variations. There are no adequate and well-controlled studies in pregnant women. Theophylline should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
🧒 Pediatric Use ▾
Pediatric Use: Theophylline is safe and effective for the approved indications in pediatric patients (see INDICATIONS AND USAGE ). The maintenance dose of theophylline must be selected with caution in pediatric patients since the rate of theophylline clearance is highly variable across the age range of neonates to adolescents (see CLINICAL PHARMACOLOGY , Table I, WARNINGS , and DOSAGE AND ADMINISTRATION , Table V). Due to the immaturity of theophylline metabolic pathways in infants under the age of one year, particular attention to dosage selection and frequent monitoring of serum theophylline concentrations are required when theophylline is prescribed to pediatric patients in this age group.
🧓 Geriatric Use ▾
Geriatric Use: Elderly patients are at a significantly greater risk of experiencing serious toxicity from theophylline than younger patients due to pharmacokinetic and pharmacodynamic changes associated with aging. The clearance of theophylline is decreased by an average of 30% in healthy elderly adults (>60 yrs) compared to healthy young adults. Theophylline clearance may be further reduced by concomitant diseases prevalent in the elderly, which further impair clearance of this drug and have the potential to increase serum levels and potential toxicity.
These conditions include impaired renal function, chronic obstructive pulmonary disease, congestive heart failure, hepatic disease and an increased prevalence of use of certain medications (see PRECAUTIONS: Drug Interactions ) with the potential for pharmacokinetic and pharmacodynamic interaction. Protein binding may be decreased in the elderly resulting in an increased proportion of the total serum theophylline concentration in the pharmacologically active unbound form. Elderly patients also appear to be more sensitive to the toxic effects of theophylline after chronic overdosage than younger patients.
Careful attention to dose reduction and frequent monitoring of serum theophylline concentrations are required in elderly patients (see PRECAUTIONS, Monitoring Serum Theophylline Concentrations , and DOSAGE AND ADMINISTRATION ). The maximum daily dose of theophylline in patients greater than 60 years of age ordinarily should not exceed 400 mg/day unless the patient continues to be symptomatic and the peak steady-state serum theophylline concentration is <10 mcg/mL (see DOSAGE AND ADMINISTRATION ). Theophylline doses greater than 400 mg/d should be prescribed with caution in elderly patients.
🆘 Overdosage ▾
OVERDOSAGE General: The chronicity and pattern of theophylline overdosage significantly influences clinical manifestations of toxicity, management and outcome. There are two common presentations: (1) acute overdose , i.e., ingestion of a single large excessive dose (>10 mg/kg) as occurs in the context of an attempted suicide or isolated medication error, and (2) chronic overdosage , i.e., ingestion of repeated doses that are excessive for the patient's rate of theophylline clearance. The most common causes of chronic theophylline overdosage include patient or care giver error in dosing, healthcare professional prescribing of an excessive dose or a normal dose in the presence of factors known to decrease the rate of theophylline clearance, and increasing the dose in response to an exacerbation of symptoms without first measuring the serum theophylline concentration to determine whether a dose increase is safe.
Severe toxicity from theophylline overdose is a relatively rare event. In one health maintenance organization, the frequency of hospital admissions for chronic overdosage of theophylline was about 1 per 1000 person-years exposure. In another study, among 6000 blood samples obtained for measurement of serum theophylline concentration, for any reason, from patients treated in an emergency department, 7% were in the 20-30 mcg/mL range and 3% were >30 mcg/mL.
Approximately two-thirds of the patients with serum theophylline concentrations in the 20-30 mcg/mL range had one or more manifestations of toxicity while >90% of patients with serum theophylline concentrations >30 mcg/mL were clinically intoxicated. Similarly, in other reports, serious toxicity from theophylline is seen principally at serum concentrations >30 mcg/mL. Several studies have described the clinical manifestations of theophylline overdose and attempted to determine the factors that predict life-threatening toxicity.
In general, patients who experience an acute overdose are less likely to experience seizures than patients who have experienced a chronic overdosage, unless the peak serum theophylline concentration is >100 mcg/mL. After a chronic overdosage, generalized seizures, life-threatening cardiac arrhythmias, and death may occur at serum theophylline concentrations >30 mcg/mL. The severity of toxicity after chronic overdosage is more strongly correlated with the patient's age than the peak serum theophylline concentration; patients >60 years are at the greatest risk for severe toxicity and mortality after a chronic overdosage.
Pre-existing or concurrent disease may also significantly increase the susceptibility of a patient to a particular toxic manifestation, e.g., patients with neurologic disorders have an increased risk of seizures and patients with cardiac disease have an increased risk of cardiac arrhythmias for a given serum theophylline concentration compared to patients without the underlying disease. The frequency of various reported manifestations of theophylline overdose according to the mode of overdose are listed in Table IV.
Other manifestations of theophylline toxicity include increases in serum calcium, creatine kinase, myoglobin and leukocyte count, decreases in serum phosphate and magnesium, acute myocardial infarction, and urinary retention in men with obstructive uropathy. Seizures associated with serum theophylline concentrations >30 mcg/mL are often resistant to anticonvulsant therapy and may result in irreversible brain injury if not rapidly controlled. Death from theophylline toxicity is most often secondary to cardiorespiratory arrest and/or hypoxic encephalopathy following prolonged generalized seizures or intractable cardiac arrhythmias causing hemodynamic compromise.
Overdose Management: General Recommendations for Patients with Symptoms of Theophylline Overdose or Serum Theophylline Concentrations >30 mcg/mL (Note: Serum theophylline concentrations may continue to increase after presentation of the patient for medical care.) W…
🧬 Clinical Pharmacology ▾
CLINICAL PHARMACOLOGY Mechanism of Action: Theophylline has two distinct actions in the airways of patients with reversible obstruction: smooth muscle relaxation (i.e., bronchodilation) and suppression of the response of the airways to stimuli (i.e., non-bronchodilator prophylactic effects). While the mechanisms of action of theophylline are not known with certainty, studies in animals suggest that bronchodilation is mediated by the inhibition of two isozymes of phosphodiesterase (PDE III and, to a lesser extent, PDE IV) while non-bronchodilator prophylactic actions are probably mediated through one or more different molecular mechanisms that do not involve inhibition of PDE III or antagonism of adenosine receptors.
Some of the adverse effects associated with theophylline appear to be mediated by inhibition of PDE III (e.g., hypotension, tachycardia, headache, and emesis) and adenosine receptor antagonism (e.g., alterations in cerebral blood flow). Theophylline increases the force of contraction of diaphragmatic muscles. This action appears to be due to enhancement of calcium uptake through an adenosine-mediated channel.
Serum Concentration-Effect Relationship: Bronchodilation occurs over the serum theophylline concentration range of 5 - 20 mcg/mL. Clinically important improvement in symptom control has been found in most studies to require peak serum theophylline concentrations >10 mcg/mL, but patients with mild disease may benefit from lower concentrations. At serum theophylline concentrations >20 mcg/mL, both the frequency and severity of adverse reactions increase.
In general, maintaining peak serum theophylline concentrations between 10 and 15 mcg/mL will achieve most of the drug's potential therapeutic benefit while minimizing the risk of serious adverse events. Pharmacokinetics: Overview Theophylline is rapidly and completely absorbed after oral administration in solution or immediate-release solid oral dosage form. Theophylline does not undergo any appreciable pre-systemic elimination, distributes freely into fat-free tissues and is extensively metabolized in the liver.
The pharmacokinetics of theophylline vary widely among similar patients and cannot be predicted by age, sex, body weight or other demographic characteristics. In addition, certain concurrent illnesses and alterations in normal physiology (see Table I) and co-administration of other drugs (see Table II) can significantly alter the pharmacokinetic characteristics of theophylline. Within-subject variability in metabolism has also been reported in some studies, especially in acutely ill patients.
It is, therefore, recommended that serum theophylline concentrations be measured frequently in acutely ill patients (e.g., at 24-hr intervals) and periodically in patients receiving long-term therapy, e.g., at 6-12 month intervals. More frequent measurements should be made in the presence of any condition that may significantly alter theophylline clearance (see PRECAUTIONS, Laboratory Tests ). Table I.
Mean and range of total body clearance and half-life of theophylline related to age and altered physiological states.* Population characteristics Total body clearance† mean (range) ǂ (mL/kg/min) Half-life Mean (range) ǂ (hr) * For various North American patient populations from literature reports. Different rates of elimination and consequent dosage requirements have been observed among other peoples. † Clearance represents the volume of blood completely cleared of theophylline by the liver in one minute. Values listed were generally determined at serum theophylline concentrations <20 mcg/mL; clearance may decrease and half-life may increase at higher serum concentrations due to non-linear pharmacokinetics. ǂ Reported range or estimated range (mean ± 2 SD) where actual range not reported. § NR =not reported or not reported in a comparable format. ¶ Median Note: In addition to the factors listed above, theophylline clearance is increased and half-life decreased by low…
🧬 Mechanism of Action ▾
Mechanism of Action: Theophylline has two distinct actions in the airways of patients with reversible obstruction: smooth muscle relaxation (i.e., bronchodilation) and suppression of the response of the airways to stimuli (i.e., non-bronchodilator prophylactic effects). While the mechanisms of action of theophylline are not known with certainty, studies in animals suggest that bronchodilation is mediated by the inhibition of two isozymes of phosphodiesterase (PDE III and, to a lesser extent, PDE IV) while non-bronchodilator prophylactic actions are probably mediated through one or more different molecular mechanisms that do not involve inhibition of PDE III or antagonism of adenosine receptors.
Some of the adverse effects associated with theophylline appear to be mediated by inhibition of PDE III (e.g., hypotension, tachycardia, headache, and emesis) and adenosine receptor antagonism (e.g., alterations in cerebral blood flow). Theophylline increases the force of contraction of diaphragmatic muscles. This action appears to be due to enhancement of calcium uptake through an adenosine-mediated channel.
📦 How Supplied / Storage and Handling ▾
HOW SUPPLIED Theo-24 (theophylline anhydrous) is supplied in extended-release capsules containing 100, 200, 300 or 400 mg of anhydrous theophylline. Theo-24 100 mg capsules are orange opaque and natural, with markings Theo-24, 100 mg, AP, and 2832, supplied as: NDC Number Size 52244-100-10 bottle of 100 Theo-24 200 mg capsules are orange opaque and clear, with markings Theo-24, 200 mg, AP, and 2842, supplied as: NDC Number Size 52244-200-10 bottle of 100 Theo-24 300 mg capsules are Swedish orange and natural, with markings Theo-24, 300 mg, AP, and 2852, supplied as: NDC Number Size 52244-300-10 bottle of 100 Theo-24 400 mg capsules are pink opaque and natural, with markings Theo-24, 400 mg, AP, and 2902, supplied as: NDC Number Size 52244-400-10 bottle of 100 STORAGE Store below 77° F (25° C).
📦 Storage and Handling ▾
STORAGE Store below 77° F (25° C).
📋 Description ▾
DESCRIPTION Theophylline Theophylline is structurally classified as a methylxanthine. It occurs as a white, odorless, crystalline powder with a bitter taste. Anhydrous theophylline has the chemical name 1H-Purine-2, 6-dione, 3, 7-dihydro-1, 3-dimethyl-, and is represented by the following structural formula: The molecular formula of anhydrous theophylline is C 7 H 8 N 4 O 2 with a molecular weight of 180.17.
Theo-24 is available as capsules intended for oral administration, containing 100 mg, 200 mg, 300 mg, or 400 mg of anhydrous theophylline per capsule, in an extended-release formulation which allows a 24-hour dosing interval for appropriate patients. Inactive ingredients are edible ink (which contains synthetic black iron oxide, FD&C Blue No. 1, FD&C Blue No.
2, FD&C Yellow No. 6, D&C Yellow No. 10, FD&C Red No.
40), ethylcellulose, gelatin, pharmaceutical glaze, colloidal silicon dioxide, starch, sucrose, talc, titanium dioxide, and coloring agents: 100 mg - includes FD&C Yellow No. 6; 200 mg - FD&C Red No. 3 and D&C Yellow No.
10; 300 mg - FD&C Blue No. 1 and FD&C Red No. 40; 400 mg - FD&C Red No.
40 and D&C Red No. 28. Theo-24 Extended-release capsules meet Drug Release Test 6 as published in the current USP monograph for Theophylline Extended-release Capsules.
This the structural formula for anhydrous theophylline.
💬 Information for Patients ▾
Information for Patients: The patient (or parent/care giver) should be instructed to seek medical advice whenever nausea, vomiting, persistent headache, insomnia or rapid heart beat occurs during treatment with theophylline, even if another cause is suspected. The patient should be instructed to contact their healthcare professional if they develop a new illness, especially if accompanied by a persistent fever, if they experience worsening of a chronic illness, if they start or stop smoking cigarettes or marijuana, or if another healthcare professional adds a new medication or discontinues a previously prescribed medication.
Patients should be informed that theophylline interacts with a wide variety of drugs (see Table II). The dietary supplement St. John's Wort (Hypericum perforatum) should not be taken at the same time as theophylline, since it may result in decreased theophylline levels.
If patients are already taking St. John's Wort and theophylline together, they should consult their healthcare professional before stopping the St. John's Wort, since their theophylline concentrations may rise when this is done, resulting in toxicity.
Patients should be instructed to inform all healthcare professionals involved in their care that they are taking theophylline, especially when a medication is being added or deleted from their treatment. Patients should be instructed to not alter the dose, timing of the dose, or frequency of administration without first consulting their healthcare professional. If a dose is missed, the patient should be instructed to take the next dose at the usually scheduled time and to not attempt to make up for the missed dose.
Patients should be instructed to take this medication each morning at approximately the same time and not to exceed the prescribed dose. Patients who require a relatively high dose of theophylline should be informed of important considerations relating to time of drug administration and meal content (see PRECAUTIONS, Drug/Food Interactions ; and DOSAGE AND ADMINISTRATION ).