Theophylline Flashcards
(12 cards)
How should theophylline be prescribed?
By brand name, due to bioavailability differences between brands. Maintain the same brand used during hospitalization.
In which conditions is plasma theophylline concentration increased?
Heart failure, hepatic impairment, and viral infections.
In which populations is plasma theophylline concentration decreased?
Smokers and people who consume alcohol.
What monitoring is required before starting theophylline?
Check urea, electrolytes (especially potassium), and liver function.
When should plasma theophylline levels be monitored?
5 days after starting.
Every 6–12 months.
3+ days after dose adjustments.
If adverse effects or drug interactions occur.
After smoking status changes.
In which patients should potassium levels be checked regularly when on theophylline?
Those on beta-2 agonists, corticosteroids, diuretics, or with hypoxia.
In whom should theophylline be used with caution?
Older adults
Those with CVD, hepatic impairment, fever, electrolyte imbalances, or thyroid dysfunction
Avoid in recent MI, acute tachycardia, porphyria, or epilepsy.
What are common adverse effects of theophylline?
GI: nausea, vomiting, reflux
Neurological: tremor, headache, insomnia
Psychiatric: anxiety
Metabolic: hypokalaemia, hyperglycaemia, hyperuricaemia
Cardiovascular: palpitations, arrhythmias
At what plasma level do theophylline side effects increase?
Above 20 mg/L, though therapeutic effect typically begins at 10–20 mg/L.
What drugs interact with theophylline and may increase toxicity risk?
Beta-2 agonists, corticosteroids, diuretics (→ hypokalaemia)
Fluvoxamine (↑ levels)
Lithium, digoxin, enzyme inhibitors (e.g., ciprofloxacin), enzyme inducers (e.g., rifampicin)
What patient advice is essential when prescribing theophylline?
Avoid over-the-counter theophylline products
Limit caffeine
Monitor regularly for interactions
Report signs of toxicity like nausea or palpitations
