Theophylline
Toxic dose is also where therapeutic effect is seen
Not a great drug.
| Uses: | bronchodilation |
|---|---|
| Mechanism of action | methylxanthine class - phosphodiesterase inhibitor → ↑ cAMP - adenosine antagonist - activates histone deacetylase 2, thereby reversing steroid resistance in treatment-refractory asthma and COPD |
| Pharmacokinetics | Absorption PO bioavailability nearly 100% Distribution 60% protein bound Metabolism liver Elimination urine, t½ 7h |
| Time course of action | |
| Adverse effects | - inodilation (may or may not be a plus, depending) - peripheral vasodilation - lowers seizure threshold - ↑ uric acid - hypokalaemia |
toxicity
clinical features, considering effects:
- A: they probably gonna get tubed if it's that bad
- B: ↑ RR
- C: hypertension, widened pulse pressure, tachycardia/SVT
- D: seizures, tremor
- E: vomiting++, dilated pupils, agitation
- Hypokalemia
- Hypomagnesemia
- Hypophosphataemia
- Hyperglycaemia
- Hypercalcemia
- Lactic acidosis
- Respiratory alkalosis
- Rhabdomyolysis