Asthma & allergy
Methylxanthine bronchodilator
Theophylline (once-daily)
Also known as: Uniphyl, Theo-24
Best time
Early evening
- 18:00–20:00
Once-daily slow-release theophylline in the evening targets night-time asthma attacks.
Moderate evidence
Supported by studies and drug pharmacology, but guidance varies between sources.
Why this time works
Evening dosing produces the highest blood levels during the early-morning hours when airways are narrowest, reducing nocturnal symptoms. It is a classic example of a drug designed around a circadian rhythm.
Body rhythm involved
Airway narrowing peaks around 04:00.