aminophylline

Drug Name
Generic Name: aminophylline (theophylline ethylenediamine)
Brand Name: Truphylline
Classification: Bronchodilator, Xanthine
Pregnancy Category C

Dosages
  • Individualize dosage: Base adjustments on clinical responses; monitor serum theophylline levels; maintain therapeutic range of 10–20 mcg/mL; base dosage on lean body mass; 127 mg aminophylline dihydrate = 100 mg theophylline anhydrous.
ADULTS
Oral

  • Acute symptoms requiring rapid theophyllinization in patients not receiving theophylline: An initial loading dose is required, as indicated below:
 Patient Group Loading  Followed by  Maintenance
 Young adult smokers 7.6 mg/kg 3.8 mg/kg q 4 hr × 3 doses 3.8 mg/kg q 6 hr
 Adult nonsmokers who are otherwise healthy 7.6 mg/kg 3.8 mg/kg q 6 hr × 2 doses 3.8 mg/kg q 8 hr
*Expressed as aminophylline
  • Long-term therapy: Usual range is 600–1,600 mg/day PO in three to four divided doses.
Rectal

  • 500 mg q 6–8 hr by rectal suppository or retention enema.
PEDIATRIC PATIENTS

Children are very sensitive to CNS stimulant action of theophylline; use caution in younger children unable to complain of minor side effects.

  • < 6 mo: Not recommended.
  • < 6 yr: Use of timed-release products not recommended.
Oral

  • Acute therapy: For acute symptoms requiring rapid theophyllinization in patients not receiving theophylline, a loading dose is required. Recommendations are as follows:
 Patient Group  Loading  Followed by  Maintenance
 Children 6 mo–9 yr 7.6 mg/kg 5.1 mg/kg q 4 hr × 3 doses 5.1 mg/kg q 6 hr
 Children 9–16 yr 7.6 mg/kg 3.8 mg/kg q 4 hr × 3 doses 3.8 mg/kg q 6 hr
  • Long-term therapy: 20.3 mg/kg or 508 mg/day (immediate-release) or 15.2 mg/kg or 508 mg/day (extended-release) PO; slow clinical adjustment of the oral preparations is preferred; monitor clinical response and serum theophylline levels. In the absence of serum levels, adjust up to the maximum dosage shown below, providing the dosage is tolerated.
 Age Maximum Daily Dose
 < 9 yr 30.4 mg/kg/day
 9–12 yr 25.3 mg/kg/day
 12–16 yr 22.8 mg/kg/day
 > 16 yr 16.5 mg/kg/day or 1,100 mg, whichever is less
*Expressed as aminophylline
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
Adverse effects
  • Serum theophylline levels < 20 mcg/mL: Adverse effects uncommon
  • Serum theophylline levels > 20–25 mcg/mL: Nausea, vomiting, diarrhea, headache, insomnia, irritability (75% of patients)
  • Serum theophylline levels > 30–35 mcg/mL: Hyperglycemia, hypotension, cardiac arrhythmias, seizures, tachycardia (> 10 mcg/mL in premature newborns); brain damage
  • CNS: Irritability (especially children); restlessness, dizziness, muscle twitching, seizures, severe depression, stammering speech; abnormal behavior characterized by withdrawal, mutism, and unresponsiveness alternating with hyperactive periods
  • CV: Palpitations, sinus tachycardia, ventricular tachycardia, life-threatening ventricular arrhythmias, circulatory failure
  • GI: Loss of appetite, hematemesis, epigastric pain, gastroesophageal reflux during sleep, increased AST
  • GU: Proteinuria, increased excretion of renal tubular cells and RBCs; diuresis (dehydration), urinary retention in men with prostate enlargement
  • Respiratory: Tachypnea, respiratory arrest
  • Other: Fever, flushing, hyperglycemia, SIADH, rash
Contraindications
  • Contraindicated with hypersensitivity to any xanthine or to ethylenediamine, peptic ulcer, active gastritis; rectal or colonic irritation or infection (use rectal preparations).
  • Use cautiously with cardiac arrhythmias, acute myocardial injury, CHF, cor pulmonale, severe hypertension, severe hypoxemia, renal or hepatic disease, hyperthyroidism, alcoholism, labor, lactation, pregnancy.
Nursing considerations
Assessment
  • History: Hypersensitivity to any xanthine or to ethylenediamine, peptic ulcer, active gastritis, cardiac arrhythmias, acute myocardial injury, CHF, cor pulmonale, severe hypertension, severe hypoxemia, renal or hepatic disease, hyperthyroidism, alcoholism, labor, lactation, rectal or colonic irritation or infection (aminophylline rectal preparations)
  • Physical: Bowel sounds, normal output; P, auscultation, BP, perfusion, ECG; R, adventitious sounds; frequency of urination, voiding, normal output pattern, urinalysis, LFTs, renal function tests; liver palpation; thyroid function tests; skin color, texture, lesions; reflexes, bilateral grip strength, affect, EEG
Interventions
  • 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.
  • Ensure that diazepam is readily available to treat seizures.
Teaching points
  • Take this drug exactly as prescribed; if a timed-release product is prescribed, take this drug on an empty stomach, 1 hour before or 2 hours after meals.
  • Do not to chew or crush timed-release preparations.
  • Administer rectal solution or suppositories after emptying the rectum.
  • It may be necessary to take this drug around-the-clock for adequate control of asthma attacks.
  • Avoid excessive intake of coffee, tea, cocoa, cola beverages, and chocolate.
  • Smoking cigarettes or other tobacco products impacts the drug’s effectiveness. Try not to smoke. Notify your health care provider if smoking habits change while taking this drug.
  • Frequent blood tests may be necessary to monitor the effect of this drug and to ensure safe and effective dosage; keep all appointments for blood tests and other monitoring.
  • You may experience these side effects: Nausea, loss of appetite (taking this drug with food may help if taking the immediate-release or liquid dosage forms); difficulty sleeping, depression, emotional lability (reversible).
  • Report nausea, vomiting, severe GI pain, restlessness, seizures, irregular heartbeat.

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