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Theophylline

Medicine levels · also printed as Theophylline level, Aminophylline level, Serum theophylline, Uniphyllin level, Phyllocontin level

Typical UK adult range10 to 20 mg/L

Target ranges are set by the treating team and printed by the lab; the printed range applies.

What this test measures

Theophylline (aminophylline when given by drip) is an older asthma and COPD medicine with a narrow band between effect and side effects, so the level is measured.

Why doctors request it

Checked when starting, when side effects such as nausea or palpitations occur, and when interacting medicines are added.

What commonly pushes it up

Some antibiotics and other medicines as a class
Heart failure and liver disease
Stopping smoking
Viral infections

What commonly pushes it down

Smoking
Some medicines as a class that speed its breakdown

Everyday reasons for a value outside the range

Smoking status changes it markedly

About the sample

Usually a trough before the next tablet.

Written by a UK consultant physician. Typical UK adult reference ranges; your laboratory's own printed range takes precedence.

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This is an educational summary of results you uploaded. It is not medical advice, a diagnosis or a treatment plan, and it does not replace the doctor who requested the test. If you are worried, or a result is marked outside range, discuss it with your doctor. Written and reviewed by a UK consultant physician. Reference ranges vary between laboratories.