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 diseaseSeizure disordersCardiac 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:AgeNeonates (term and premature)Children <1 yearElderly (>60 years)Concurrent DiseasesAcute pulmonary edemaCongestive heart failureCor-pulmonaleFever; >102º for 24 hours or more; or lesser temperature elevations for longer periodsHypothyroidismLiver disease; cirrhosis, acute hepatitisReduced renal function in infants <3 months of ageSepsis with multi-organ failureShockCessation Of SmokingDrug 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 clinician 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 beta2-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 clinician 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).