Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (898 page)

   A cardiac glycoside derived from
Digitalis lanata
consisting of a steroid nucleus and a lactone coupled with sugar moieties.

   Other name: Lanoxin.

   
Normal therapeutic range:
0.8–2.0 ng/mL (1.2–2.6 nmol/L).

   Use

   Treatment of CHF and atrial fibrillation/flutter

   Interpretation

   
Toxic range:
>2.5 ng/mL, but 10% of patients may show toxicity at <2 ng/mL.

   Toxicity may be observed at a lower serum concentration in presence of hypokalemia, hypercalcemia, hypomagnesemia, hypoxia, and heart disease.

   Increased with coadministration of

   Quinidine

   Verapamil

   Amiodarone

   Indomethacin

   Cyclosporin A