|
|
|
Pronunciation |
|
(am
in OFF i
lin) |
|
|
U.S. Brand
Names |
|
Phyllocontin®;
Truphylline® |
|
|
Generic
Available |
|
Yes |
|
|
Synonyms |
|
Theophylline Ethylenediamine |
|
|
Pharmacological Index |
|
Theophylline Derivative |
|
|
Use |
|
Bronchodilator in reversible airway obstruction due to asthma or COPD;
increase diaphragmatic contractility; neonatal idiopathic apnea of
prematurity |
|
|
Pregnancy Risk
Factor |
|
C |
|
|
Adverse
Reactions |
|
Uncommon at serum theophylline concentrations less than or equal to 20
mcg/mL
1% to 10%:
Cardiovascular: Tachycardia
Central nervous system: Nervousness, restlessness
Gastrointestinal: Nausea, vomiting
<1%:
Central nervous system: Insomnia, irritability, seizures
Dermatologic: Skin rash
Gastrointestinal: Gastric irritation
Neuromuscular & skeletal: Tremor
Miscellaneous: Allergic reactions |
|
|
Drug
Interactions |
|
Decreased effect/increased toxicity: Changes in diet may affect the
elimination of theophylline; charcoal-broiled foods may increase elimination,
reducing half-life by 50%; see table for factors affecting serum levels.
Decreased theophylline level
Aminoglutethimide, barbiturates, carbamazepine, charcoal, high protein/low
carbohydrate diet, hydantoins, isoniazid, I.V. isoproterenol, ketoconazole, loop
diuretics, phenobarbital, phenytoin, rifampin, smoking (cigarettes, marijuana),
sulfinpyrazone, sympathomimetics
Increased theophylline level
Allopurinol (>600 mg/day), beta-blockers, calcium channel blockers,
carbamazepine, CHF, cimetidine, ciprofloxacin, cor pulmonale, corticosteroids,
disulfiram, ephedrine, erythromycin, fever/viral illness, hepatic cirrhosis,
influenza virus vaccine, interferon, isoniazid, loop diuretics, macrolides,
mexiletine, oral contraceptives, propranolol, quinolones, thiabendazole, thyroid
hormones, troleandomycin |
|
|
Stability |
|
Do not use solutions if discolored or if crystals are
present |
|
|
Mechanism of
Action |
|
Causes bronchodilatation, diuresis, CNS and cardiac stimulation, and gastric
acid secretion by blocking phosphodiesterase which increases tissue
concentrations of cyclic adenine monophosphate (cAMP) which in turn promotes
catecholamine stimulation of lipolysis, glycogenolysis, and gluconeogenesis and
induces release of epinephrine from adrenal medulla cells |
|
|
Pharmacodynamics/Kinetics |
|
Pharmacokinetic parameters are those of theophylline
Half-life: Highly variable and dependent upon age, liver function, cardiac
function, lung disease, and smoking history
Time to peak serum concentration:
Oral: 1 hour
Uncoated tablet: 2 hours
Chewable tablet: 1-1.5 hours
Enteric-coated tablet: 5 hours
I.V.: Within 30 minutes |
|
|
Usual Dosage |
|
Neonates: Apnea of prematurity:
Loading dose: 5 mg/kg for one dose
Maintenance: I.V.:
0-24 days: Begin at 2 mg/kg/day divided every 12 hours and titrate to desired
levels and effects
>24 days: 3 mg/kg/day divided every 12 hours; increased dosages may be
indicated as liver metabolism matures (usually >30 days of life); monitor
serum levels to determine appropriate dosages
Theophylline levels should be initially drawn after 3 days of therapy; repeat
levels are indicated 3 days after each increase in dosage or weekly if on a
stabilized dosage
Treatment of acute bronchospasm:
Loading dose (in patients not currently receiving aminophylline or
theophylline): 6 mg/kg (based on aminophylline) administered I.V. over 20-30
minutes; administration rate should not exceed 25 mg/minute (aminophylline)
Approximate I.V. maintenance dosages are based upon continuous
infusions; bolus dosing (often used in children <6 months of age) may be
determined by multiplying the hourly infusion rate by 24 hours and dividing by
the desired number of doses/day
6 weeks to 6 months: 0.5 mg/kg/hour
6 months to 1 year: 0.6-0.7 mg/kg/hour
1-9 years: 1-1.2 mg/kg/hour
9-12 years and young adult smokers: 0.9 mg/kg/hour
12-16 years: 0.7 mg/kg/hour
Adults (healthy, nonsmoking): 0.7 mg/kg/hour
Older patients and patients with cor pulmonale, patients with congestive
heart failure or liver failure: 0.25 mg/kg/hour
Dosage should be adjusted according to serum level measurements during the
first 12- to 24-hour period; avoid using suppositories due to erratic,
unreliable absorption.
Rectal: Adults: 500 mg 3 times/day |
|
|
Dietary
Considerations |
|
Food does not appreciably affect absorption; avoid extremes of dietary
protein and carbohydrate intake; limit charcoal-broiled
foods |
|
|
Administration |
|
Dilute with I.V. fluid to a concentration of 1 mg/mL and infuse over 20-30
minutes; maximum concentration: 25 mg/mL; maximum rate of infusion: 0.36
mg/kg/minute, and no greater than 25 mg/minute |
|
|
Dental Health: Local
Anesthetic/Vasoconstrictor
Precautions |
|
No information available to require special precautions |
|
|
Dental Health:
Effects on Dental Treatment |
|
Prescribe erythromycin with caution to patients taking theophylline products.
Erythromycin will delay the normal metabolic inactivation of theophyllines
leading to increased blood levels; this has resulted in nausea, vomiting and CNS
restlessness |
|
|
Patient
Information |
|
Do not drink or eat large quantities of caffeine-containing beverages or food
(colas, coffee, chocolate); remain in bed for 15-20 minutes after inserting
suppository |
|
|
Nursing
Implications |
|
Avoid I.M. injection, too painful; do not inject I.V. solution faster than 25
mg/minute; oral and I.V. should be administered around-the-clock rather than 4
times/day, 3 times/day, etc, (ie, 12-6-12-6, not 9-1-5-9) to promote less
variation in peak and trough serum levels; do not crush sustained release drug
products; do not crush enteric coated drug product; encourage patient to drink
adequate fluids (2 L/day) to decrease mucous viscosity in airways
Monitor vital signs, I & O, serum concentrations, and CNS effects
(insomnia, irritability) |
|
|
Dosage Forms |
|
Injection, I.V.: 25 mg/mL (10 mL, 20 mL)
Liquid, oral: 105 mg/5 mL (240 mL)
Suppository, rectal (Truphylline®): 250 mg, 500 mg
Tablet: 100 mg, 200 mg
Controlled release [12 hours] (Phyllocontin®): 225 mg
|
|
|
References |
|
Delaforge M and Sartori E,
"In Vivo Effects of Erythromycin, Oleandomycin, and Erythralosamine Derivatives on Hepatic Cytochrome P-450,"
Biochem Pharmacol, 1990, 40(2):223-8.
Ludden TM, "Pharmacokinetic Interactions of the Macrolide Antibiotics,"
Clin Pharmacokinet, 1985, 10(1):63-79.
|
|
Copyright © 1978-2000 Lexi-Comp Inc. All Rights Reserved
| |