Aminophylline is a theophylline-based preparation that may be used in place of, or in addition to, salbutamol at this stage.

Aminophylline
Presentation	It is presented in a 10 ml ampoule, so further dilution is not required.
Dose	50 mg titrated to effect over 20 minutes.
Mechanism of action	It acts as a non-specific phosphodiesterase inhibitor to increase cAMP within cells, leading to smooth muscle relaxation.
Side-effects	Should not be used in patients who are normally controlled on a preparation containing theophylline, because the plasma concentrations may easily enter the toxic range and result in seizure activity and arrhythmias.