LEVOTHYROXINE AND THEOPHYLLINE

Thyroid status may affect the rate at which theophylline is metabolised: in hypothyroidism it is decreased. As thyroid function is corrected with e.g. levothyr- oxine, metabolism increases and so larger doses of theophylline are needed.
Monitor the outcome of resolving hypothyroidism, checking that the effects of theophylline are adequate. Monitor theophylline levels as necessary.