OXTRIPHYLLINE

OXTRIPHYLLINE (ox-trye'fi-lin) Choledyl SA Classifications: bronchodilator (respiratory smooth muscle relaxant); xanthine; Therapeutic: bronchodilator Prototype: Theophylline Pregnancy Category: C

Availability

400 mg, 600 mg sustained release tablets

Action

Choline salt of theophylline. Relaxes smooth muscle by direct action, particularly of bronchi and pulmonary vessels, and stimulates medullary respiratory center with resulting increase in vital capacity.

Therapeutic Effect

Relaxes bronchi smooth muscle and stimulates respiratory center in the medulla of the brain.

Uses

As bronchodilator to control asthma or COPD.

Contraindications

Hypersensitivity to xanthines; coronary artery disease; renal or hepatic impairment. Safe use during pregnancy (category C), lactation, or in children <1 y is not established.

Cautious Use

Peptic ulcer; prostatic hypertrophy; diabetes mellitus; glaucoma.

Route & Dosage

Asthma, COPD Adult: PO 4.7 mg/kg (usual dose 200 mg) q8h Child: PO 1–9 y, 6.2 mg/kg q6h; 9–16 y, adult smoker, 4.7 mg/kg (usual dose 200 mg) q6h

Administration

Oral

• Give on an empty stomach (30 min to 1 h before or 2 h after meals); may be taken after meals and at bedtime to reduce GI distress. Sustained release tablet permits dosing q12h.
• Ensure that sustained release form is not chewed or crushed. It must be swallowed whole.
• Protect elixir from light.

Adverse Effects (≥1%)

CNS: Restlessness, dizziness, insomnia, convulsions, muscle twitching. CV: Palpitation, tachycardia, flushing, hypotension. GI: Nausea, vomiting, anorexia, epigastric pain, diarrhea, activation of peptic ulcer. Urogenital: Transient urinary frequency, kidney irritation. Body as a Whole: Urticaria, fever, dehydration.

Interactions

Drug: Lowers lithium levels; cimetidine, high dose allopurinol (600 mg/d), ciprofloxacin, erythromycin, troleandomycin can significantly increase levels. Herbal: St. John's wort may decrease plasma levels.

Pharmacokinetics

Absorption: Well absorbed from GI tract. Duration: 4–8 h; varies with age, smoking, and liver function. Distribution: Crosses placenta; distributed into breast milk. Metabolism: Extensively in liver. Elimination: Parent drug and metabolites excreted by kidneys. Half-Life: 4 h in adults.

Nursing Implications

Note: See theophylline for numerous additional nursing implications.

Assessment & Drug Effects

• Determine patient's tobacco use. Cigarette smoking may alter hepatic microsomal enzyme activity and indicate increase in dosage.
• Use safety precautions with older adults during early therapy; dizziness is a relatively common adverse effect.
• Monitor vital signs and I&O. Improvement in quality of pulse and respiration and diuresis are expected clinical effects.
• Observe and report early signs of possible toxicity: anorexia, nausea, vomiting, dizziness, shakiness, restlessness, abdominal discomfort, irritability, palpitation, tachycardia, marked hypotension, cardiac arrhythmias, seizures.

Patient & Family Education

• Report gastric distress, palpitation, and CNS stimulation (irritability, restlessness, nervousness, insomnia) to physician. Reduction in dosage may be indicated.
• Limit caffeine intake; it may increase incidence of adverse effects.
• Do not take OTC medications, especially cough suppressants, which may cause retention of secretions and CNS depression, without consulting physician.
• Drink adequate fluids (at least 2000 mL/d) to decrease viscosity of airway secretions.

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Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug