Examples:
- Aminophylline – inj., p.o.
- Theophylline (Theodur) – inj., p.o.
These are easy to recognize because they end in -phylline. The theophyllines cause bronchodilation. They do so by relaxing the smooth muscle surrounding the bronchioles. When the smooth muscle relaxes, the bronchioles open up and breathing becomes easier. It’s directly related to caffeine so it acts like a diuretic as well so patients will go to the bathroom more often.
If we notice tachycardia, this is a warning sign and if we don’t heed this warning, then we could have seizures. We don’t see theophyllines in the ambulatory setting because we have better options (the leukotriene receptor antagonists) but hospitals use theophyllines intravenously.
- Bronchodilation (smooth muscle effect)
- Diuretic effect (chemically related to caffeine)
- Increases heart rate at high doses
- Induces seizures at toxic doses
