PDR for Herbal Medicines

HERBAL MONOGRAPHS DIGITALIS LANATA/251

Leaves, Stem and Root: Digitalis lanata is a herbaceous

biennial or perennial, upright, up to 1.2 m high. The leaves

are sessile, simple, narrow-lanceolate, 15 to 35 cm long,

entire and ciiiate in the upper area of the shoot axis. The

stem is upright, usually green, grooved-edged, usually

glabrous below and long woolly-haired in the upper half.

The plant has a primary root with no shoot-bearing roots.

A-series (aglycone digitoxigenin): including lanatoside A
(0.05 to 0.25%) glucodigifucoside (0.01 to 0.15%), glucoe-
M* vatromonoside (0.02 to 0.05%), digitoxin, alpha- and beta-
acetyldigoxin

E-series (aglycone gitaloxigenin): lanatoside E, glucovere-

doxin (0.01 to 0.14%), glucoverodoxin (0.02 to 0.12%),

gitaloxin

Pregnane derivatives: including digifolein, glucodigifolein,

diginin, digipronin, lanafolein, gitonine

Steroid saponins: including lanagitosides I and II, tigonin,

desglucolanatigonin, aglycones including tigogenin, diga-

logenin, digitogenin, gitogenin

EFFECTS

The cardioactive cardenolide glycosides contained in the

drug are positively inotropic and negatively chronotropic.

Digitalis lanata is known to be highly resorbent when

administered orally. It produces rapid results and wide-

ranging effects; has strong diuretic properties; is quickly

abating; and demonstrates good tolerability. Digitalis lanata

has three times the physiological effect of Digitalis purpurea

and is preferred for its fast-acting effect. Despite these

qualities, the drug is now obsolete and has been replaced by

pure cardenolide glycosides.

INDICATIONS AND USAGE

Because of the unsatisfactory reproducibility during produc-

tion, this drug is obsolete today; the pure cardenolide

glycosides are used. The simultaneous administration of

arrhythmogenic substances (sympathomimetics, methyl xan-

thines, phosphodiestrase inhibitors, quinidine) increases the

risk of cardiac arrhythmias.

PRECAUTIONS AND ADVERSE REACTIONS

General: Because of the difficulties involved in standardiz-

ing the drug, the administration of pure glycosides is to be

preferred (digitoxin, digoxin, alpha-acetyldigoxin, beta-ace-

tyldigoxin, lanatoside C, deslanoside). Patients receiving no

more than therapeutic dosages might experience the follow-

ing side effects: hypertonias in gastrointestinal area, loss of

appetite, vomiting, diarrhea and headache.

Drug Interactions: Neither the drug nor pure glycosides

should be administered in the presence of first- and second-

degree AV-Block, hypercalcemia, hypokaliemia, hypertro-

phic cardiomyopathy, carotid sinus syndrome, ventricle

tachycardia, thoracic aortic aneurysm or WPW syndrome.

OVERDOSAGE

With overdosage, in addition to the symptoms above, the

following can also occur:

Heart: Cardiac rhythm disorders as serious as life-threaten-

ing ventricular tachycardias and atrial tachycardias with

atrioventricular block.

Central nervous system: Dizziness, vision disorders, depres-

sions, states of confusion, hallucinations, psychoses.

Lethal dosages (for humans, 2 to 3 g of the drug) initially

lead to signs of nausea, vomiting and diarrhea caused by

irritation of the gastrointestinal tract. Slowed pulse, extrasys-

toles and conduction disturbances result from resorption.

These are followed by ventricular fibrillation and later death

from cardiac arrest.

The first-aid measures to be taken with poisonings are gastric

lavage and instillation of medicinal charcoal. All otherr

measures proceed according to the symptoms: careful

potassium substitution for potassium; phenytoin as an

antiarrhythmic for ectopic stimulation formation in the

ventricle; lidocaine for ventricular extrasystole; atropine for

partial atrioventricular block.

The prophylactic insertion of a cardiac pacemaker is

recommended. Hemoperfusion for the elimination of the

glycosides and cholestyramine administration for the inter-

ruption of the enterohepatic circulation are possible.

Habitat: The plant's habitat extends from Greece and the

Balkans across the northern coast of the Black Sea to the

Caucasus and the Caspian Sea.

Production: Woolly foxglove leaves are the dried leaves of

Digitalis lanata. Annual cultivation begins with sowing in

April; harvesting is between September and November. The

roughly cut leaves are dried for 10 to 12 hours at 50° C.

ACTIONS AND PHARMACOLOGY

COMPOUNDS

Cardioactive steroid glycosides (cardenolides) (0.5 to 1.5%)

of the following series, including:

B-series (aglycone gitoxigenin): lanatoside B (0.01 to

0.15%), glucogitoroside (0.02 to 0.12%), Digitalinum verum

(0.02 to 0.12%), gitoxin, alpha- and beta-acetylgitoxin

C-series (aglycone digoxigenin): lanatoside C (0.08 to

0.24%), desacetyl lanatoside C, digoxin

D-series (aglycone diginatigenin): lanatoside D, diginatin,

diginatigenin gitaloside