Card Set Information
What is theophylline used to treat?
COPD (chronic bronchitis, ephysema)
What is the MOA of theophylline?
: antagonism of adenosine receptors, inhibition of phosphodiesterase (increase cAMP)
Enhances contractile ability of the diaphragm (helps break up mucus in the lungs and gets mucus moving)
What is aminophylline?
derivative of theophylline
How is theophylline dosed?
Use ABW for dosing unless the patient is obese, then use IBW
For every 1 mg/kg of theophylline, blood concentrations will rise ~2 mg/L
What is the LD of theophylline?
LD is optional for patients who have had previous doses in the past 24 hours
Must use IV or rapid-release oral products
2-3 mg/kg (for patients who have received theophylline in the past 24 hours)
What is the maintenance dose for theophylline?
: 10 mg/kg/day (max 900mg daily)
decreased to 5 mg/kg/day in patients w/ heart failure or liver dysfunction (max 400mg daily)
SR = split dose in half
IR = split into 4 doses
IV continuous infusion: 0.5 mg/kg/hr
What is the therapeutic range for theophylline?
: 5-15 mg/L
serum concentrations up to 20mg/L may be acceptable in some patients
Neonates: 6-13 mg/L
What are the AE (within therapeutic range) of theophylline?
What AE can be experienced with theophylline serum concentrations of 20-30 mg/L?
What AE can be experienced with theophylline serum concentrations > 40 mg/L?
Life threatening arrhythmias
ventricular tachycardia, fibrillations, or PVCs
What is the absorption of theophylline?
S = 1 for theophylline
S = 0.8 for aminophylline
Accelerated absorption and potentially toxic concentration of theophylline may occur if once-daily formulations are administered with food
Absorption greatly increased when taken with food
Take 1 hour before or 2 hours after eating
What is the distribution of theophylline?
Vd = 0.4 - 0.6 L/kg
Remains stable regardless of concomitant disease states
40% bound to plasma proteins (limited effect of clearance)
What is the metabolism of theophylline?
>90% hepatic metabolism
, 2E1, 3A4
Leads to hydroxylation, demethylation, or methylation of theophylline
Half-life is variable and depends on clearance factors
How is theophylline excreted?
10% unchanged in the urine
Dosage adjustment not necessary in patients with renal impairment
Removed by hemodialysis (dosing should occur after dialysis)
What is the half-life of theophylline?
rages from 5-24 hours
longer in neonates and premature neonates
accelerated in children 1-9 years
may be prolonged in patients > 65 years
What drugs will increase the clearance of theophylline?
Inducers of 1A2 and 3A4: smoking, phenytoin, carbamazepine, phenobarbital, rifampin
Diet:charbroiled foods, low carbohydrates, high protein
What drugs decrease the clearance of theophylline?
Inhibitors of 1A2 and 3A4:
ciprofloxacin, azoles, clarithromycin, erythromycin, telitrhomycin, protease inhibitors, verapamil, oral contraceptives,
Others: cirrhosis, acute hepatitis, heart failure, hypothyroidism, diet (low protein, high carbs)