Indicator Explainer
Theophylline
A natural alkaloid derivative of xanthine isolated from the plants Camellia sinensis and Coffea arabica. Theophylline appears to inhibit phosphodiesterase and prostaglandin production, regulate calcium flux and intracellular calcium distribution, and antagonize adenosine. Physiologically, this agent relaxes bronchial smooth muscle, produces vasodilation (except in cerebral vessels), stimulates the CNS, stimulates cardiac muscle, induces diuresis, and increases gastric acid secretion; it may also suppress inflammation and improve contractility of the diaphragm. (NCI04)
This page explains what the indicator is and how results are interpreted in general terms. Reference ranges depend on the laboratory, the method, and your own situation — no single “normal value” applies to everyone. This page is health information, not a diagnosis. For symptoms, treatment, or urgent concerns, contact a healthcare professional.
When it is tested
Source: National Cancer Institute, NCI Thesaurus 26.09d, C872. NCI definition, reproduced without modification under CC BY 4.0. Source identity and definition checked automatically on 2026-10-20. No individual clinical interpretation or human reviewer is asserted.
Reading results
Reference intervals and interpretation depend on the laboratory, specimen, method and clinical context. This source definition is educational information; it does not establish a diagnosis, product approval or suitability for an individual.
Also Known As
References
- NCI Thesaurus 26.09d — Theophylline (C872)
- Source: National Cancer Institute, NCI Thesaurus 26.09d, C872. NCI definition, reproduced without modification under CC BY 4.0.
- A modular toolkit for theophylline-dependent synthetic auxotrophs via riboswitch-gated essential genes. — PLoS One, 2026-10-08 (PMID 42848817; literature)
- An aptamer-regulated CRISPR/Cas12a system based on split crRNA for theophylline and tobramycin detection. — Anal Methods, 2026-09-14 (PMID 42734255; literature)
- Low-dose theophylline in mild-to-moderate COPD: A physiological signal without clear clinical benefit? — Pulmonology, 2026-09-14 (PMID 42733322; literature)