Aminophylline; Theophylline Ethylenediamine

Aminophylline (theophylline ethylenediamine)

Brand Name: Truphylline

Pregnancy Category C

Drug classes: Bronchodilator, Xanthine

Therapeutic actions

Relaxes bronchial smooth muscle, causing bronchodilation and increasing vital capacity, which has been impaired by bronchospasm and air trapping; in higher concentrations, it also inhibits the release of slow-reacting substance of anaphylaxis (SRS-A) and histamine.

 

Indications

· Symptomatic relief or prevention of bronchial asthma and reversible bronchospasm associated with chronic bronchitis and emphysema

· Unlabeled uses: respiratory stimulant in Cheyne-Stokes respiration; treatment of apnea and bradycardia in premature babies

 

 

Contraindications

· Contraindicated with hypersensitivity to any xanthine or to ethylenediamine, peptic ulcer, active gastritis; rectal or colonic irritation or infection (use rectal preparations).

Adverse effects

Irritability (especially children); restlessness, dizziness, muscle twitching, convulsions, severe depression, stammering speech; abnormal behavior characterized by withdrawal, mutism, and unresponsiveness alternating with hyperactive periods, Palpitations, sinus tachycardia, ventricular tachycardia, life-threatening ventricular arrhythmias, circulatory failure, Loss of appetite, hematemesis, epigastric pain, gastroesophageal reflux during sleep, increased AST, Proteinuria, increased excretion of renal tubular cells and RBCs; diuresis (dehydration), urinary retention in men with prostate enlargement, Tachypnea, respiratory arrest, Fever, flushing, hyperglycemia, SIADH, rash

 

Drug Interactions:

· Increased effects with cimetidine, erythromycin, troleandomycin, clindamycin, lincomycin, influenza virus vaccine, oral contraceptives

· Possibly increased effects with thiabendazole, rifampin, allopurinol

· Increased cardiac toxicity with halothane; increased likelihood of seizures when given with ketamine; increased likelihood of adverse GI effects when given with tetracyclines

· Increased or decreased effects with furosemide, levothyroxine, liothyronine, liotrix, thyroglobulin, thyroid hormones

· Decreased effects in patients who are cigarette smokers (1–2 packs per day); theophylline dosage may need to be increased 50%–100%

· Decreased effects with phenobarbital, aminoglutethimide

· Increased effects, toxicity of sympathomimetics (especially ephedrine) with theophylline preparations

· Decreased effects of phenytoin and theophylline preparations when given concomitantly

· Decreased effects of lithium carbonate, nondepolarizing neuromuscular blockers given with theophylline preparations

· Mutually antagonistic effects of beta-blockers and theophylline preparations

 

Interaction with Food:

· Elimination is increased by a low-carbohydrate, high-protein diet and by charcoal broiled beef

· Elimination is decreased by a high-carbohydrate, low-protein diet

· Food may alter bioavailability and absorption of timed-release theophylline preparations, causing toxicity. These forms should be taken on an empty stomach

 

Interaction with lab test

· Interference with spectrophotometric determinations of serum theophylline levels by furosemide, phenylbutazone, probenecid, theobromine; coffee, tea, cola beverages, chocolate, acetaminophen cause falsely high values

· Alteration in assays of uric acid, urinary catecholamines, plasma free fatty acids by theophylline preparations

 

Nursing considerations

· Administer to pregnant patients only when clearly needed--neonatal tachycardia, jitteriness, and withdrawal apnea observed when mothers received xanthines up until delivery.

· Caution patient not to chew or crush enteric-coated timed-release forms.

· Give immediate-release, liquid dosage forms with food if GI effects occur.

· Do not give timed-release forms with food; these should be given on an empty stomach 1 hr before or 2 hr after meals.

· Maintain adequate hydration.

· Monitor results of serum theophylline levels carefully, and arrange for reduced dosage if serum levels exceed therapeutic range of 10–20 mcg/mL.

· Take serum samples to determine peak theophylline concentration drawn 15–30 min after an IV loading dose.

· Monitor for clinical signs of adverse effects, particularly if serum theophylline levels are not available.

· Maintain diazepam on standby to treat seizures.