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Apo-Theo LA

Theophylline Anhydrous
Sustained-release Tablets 100, 200 and 300mg



Theophylline relaxes the smooth muscle of the bronchial airways and pulmonary blood vessels to relieve bronchospasm and increase flow mates and vital capacity. It also produces other actions typical of the xanthine derivatives : coronary vasodilatation, diuresis, increase in gastric secretion, and cardiac, cerebral, and skeletal muscle stimulation. The actions of theophylline may be mediated through inhibition of phosphodiesterase and a resultant increase in intracellular cyclic adenosine monophosphate, but the exact mechanism(s) has not been determined. Theophylline is usually readily absorbed and distributed into all body compartments. Protein binding accounts for some 55 - 65%. The liver is the primary site of metabolism. The therapeutic serum concentration of theophylline is accepted as 10 to 20µg/mL (55 - 110µmol/L); levels above 20µg/mL are associated with toxic reactions. The pharmacokinetics of theophylline are influenced by a number at variables such as : age, disease stale, smoking, concomitant medication. Therefore the optimum therapeutic maintenance dose should be determined by individual titration.

APO-THEO LA Tablets are sustained-release tablets which produce peak blood levels between 5 - 8 hours after dosing in adults. Once the steady state level has been reached (3 days), the therapeutic blood levels persist for 12 hours in most adult patients. The mean elimination half-life of theophylline in nonsmoking adults is about 8 hours. The degree of fluctuation between peak trough theophylline levels can be defined as follows :

% Theophylline Fluctuation Nonsmoking Adults
Theophylline sustained-release tablets 200, 300mg 27%
Theophylline sustained-release tablets 100mg 34%


APO-THEO LA (theophylline) tablets are indicated for the symptomatic treatment of reversible bronchospasm associated with asthma, chronic bronchitis, emphysema and related bronchospastic disorders.


The most common adverse reactions are nausea, vomiting, epigastric pain, headache and tremor. These are usually early signs of toxicity; however, with high doses cardiac arrhythmias or seizures may be the first signs to appear. Adverse reactions reported with theophylline preparations include :
Gastrointestinal: nausea, vomiting, epigastric pain, hematemesis, diarrhea, anorexia, reactivation of peptic ulcer, intestinal bleeding. Central Nervous System: headaches, irritability, restlessness, insomnia, hyperactivity. reflex hyperexcitability, muscle twitching, clonic and tonic generalized convulsions.

Cardiovascular: palpitation, tachycardia, extrasystoles, flushing, hypotension, circulatory failure, life-threatening ventricular arrhythmias. Respiratory: tachypnea.
Renal: albuminuria, diuresis and hematuria.
Others: hyperglycemia and inappropriate ADH syndrome.


In clinical situations where immediate bronchodilatation is required, such as status asthmaticus, APO-THEO LA (theophylline) is not suitable.

Since theophylline has a narrow therapeutic index, the margin of safety above therapeutic doses is small. In patients showing intolerance to theophylline, the therapy should be reassessed.

Theophylline clearance can be changed by various disease states, as well as by the age of the patient, concomitant use of other medications and lifestyle habits (see PRECAUTIONS).

The use of APO-THEO LA in children under the age of twelve years is not recommended.


APO-THEO LA (theophylline) tablets should be swallowed whole. Do not break, chew or crush.
Marked differences in serum levels may be seen in patients receiving the same theophylline dose. This may be explained by differences between patients in the rate of metabolism.

Smokers and children are usually high metabolizers. Dosage regimens should therefore be individuals.

Theophylline half-life is shorter in smokers than in nonsmokers. Smokers may require larger or more frequent doses of theophylline. Ideally, serum theophylline levels should be monitored in all patients and a theophylline half-life calculated which would enable doses and dosing regimens to be tailored to each patient to maintain a therapeutic level, to ensure optimal clinical response and to avoid toxicity.

The incidence of toxicity increases at serum theophylline levels greater than 15mg/mL (82.5µmol/L) and levels above 20µg/mL (110µmol/L) are usually quite toxic in most adult patients. High serum levels may be seen in some patients receiving doses considered to be conventional. The possibility of overdose should therefore not be considered with large doses only.


Overdosage of theophylline may cause peripheral vascular collapse.


Reduced theophylline clearance has been documented in the following readily identifiable groups:
1. patients with impaired renal or hepatic function;
2. patients over 55 years of age, particularly males and those with chronic lung disease;
3. those with cardiac failure from any cause;
4. patients taking certain drug (i.e. macrolide antibiotics and cimetidine). Decreased clearance may be associated with either influenza immunization or active infection with influenza.

Laboratory monitoring of serum theophylline is especially appropriate in the above individuals to maintain an appropriate theophylline dosage.

Serious side effects such as tachycardia, arrhythmia, seizures, vascular collapse and even death may occur without warning and may not be receded by less severe symptoms such as nausea and restlessness.

Use with caution in patients with severe cardiac disease, severe hypoxemia, hypertension, hyperthyroidism, acute myocardial injury, cor pulmonale, congestive heart failure, liver disease, in the elderly (especially males).


Patients with congestive heart failure frequently have markedly prolonged serum levels with theophylline persisting in serum for long periods following discontinuation of the drug.

Theophylline may occasionally act as a local irritant to the gastrointestinal tract although gastrointestinal symptoms are more common centrally mediated and associated with serum drug concentrations over 20µg/mL (110µmol/L).


Theophylline increases gastric secretion, and caution should be exercised in patients with a history of peptic ulcer.

Although APO-THEO LA has pharmacokinetic properties similar to other controlled-release theophylline products, it is not possible to ensure interchangeability between different products. Careful clinical monitoring is required when chancing from one drug product to another.


The concurrent administration of other theophylline derivatives along with APO-THEO LA is not recommended.

Laboratory Test Interactions
In the interpretation of biochemistry tests, it should be remembered that theophylline may cause an elevation of urine catecholamines and plasma free fatty acids.

When plasma levels of theophylline are measured by spectrophotometric methods, coffee, tea, cola beverages, chocolate and acetaminophen contribute to falsely high values.

When a high pressure liquid chromatography (HPLC) method is used, plasma theophylline concentration may be falsely increased by caffeine, some cephalosporin and sulfa medications.

Food Interaction
Theophylline clearance is increased when diet includes a low carbohydrate, high protein intake, or a high carbohydrate, low protein intake and there is a chronic ingestion of charcoal broiled meats. However, the administration of APO-THEO LA with meals appears not to significantly effect the amount of theophylline released from APO-THEO LA tablets.

Usage in Pregnancy and Lactation
Theophylline crosses the placental barrier and also passes freely into breast milk, where concentrations are similar to plasma levels. Safe use in pregnancy has not been established relative to possible adverse effects on fetal development, but neither have adverse effects on fetal development been established. Therefore, use of theophylline for uncontrolled asthma in pregnant women and nursing mothers should be balanced against the risk of potential effects on the fetus or on the nursing newborn.


APO-THEO LA (theophylline) is contraindicated in patients with :
• hypersensitivity to theophylline or xanthine derivatives;
• peptic ulcer;
• coronary artery disease (when, in the physicians judgement, myocardial stimulation might prove harmful).

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