Arnicae Flores

Arnica-flowers

Arnica-flowers. The flower-heads of Arnica montana Linné (Nat. Ord. Compositae.)

Arnicae Radix

Arnica-root. The rhizoma and roots of Arnica montana. Racine d'arnica, Fr.; Arnicawurzel, Ger.

Extractum Arnicae Radicis

Extract of arnica-root. Dose, gr. j— gr. iij.

Extractum Arnicae Radicis Fluidum

Fluid extract of arnica-root. Dose, τη v—τη x.

Tinctura Arnicae Radicis

Tincture of arnica-root. Dose, τη x—

τη XXX.

Tinctura Arnicae Florum

Tincture of arnica-flowers. Dose, τη x — 3 ss.

Composition

The chemistry of arnica has not as yet been thoroughly elucidated. Walz has isolated a principle (arnicine). The root contains an essential oil on which depends, in great part, its physiological activity. The oil is a complex substance. One of its most important constituents is trimethylamine, or an analogous principle.

Antagonists and Incompatibles

The actions of arnica are antagonized by ammonia, alcoholic stimulants, opium, camphor, etc.             

Synergists

Aconite, veratrum viride, digitalis, and arterial sedatives generally, increase the effects of arnica.

Physiological Actions

Arnica excites considerable irritation of the skin, if the contact be sufficiently prolonged. It produces when swallowed a sense of heat and acridity in the fauces, and increases the flow of saliva. It is decidedly irritant to the stomach, and causes in large doses nausea and vomiting, and choleraic diarrhoea. Its active principles diffuse into the blood. In small medicinal doses arnica increases the action of the heart and arteries, and excites the functions of the skin and kidneys. In large doses, probably after a short stage of excitement, depression of the circulation, of the respiration, and of the animal temperature, ensues; violent headache is experienced, the pupils are dilated, and paresis of the muscular system comes on. In toxic doses arnica paralyzes the nervous system of animal and organic life, and death ensues in a condition of collapse.

Therapy

In febrile diseases and inflammations, when there is sthenic reaction, arnica in full doses depresses the action of the heart and lowers the arterial tension. It is, therefore, antipyretic. For the production of this effect, an infusion is probably a better preparation than the tincture. When, however, in febrile diseases there is present the condition of asthenia, small doses of the tincture (five minims) are to be preferred. That this remedy will produce different results, in small or large doses, need not occasion surprise. It is conceded on all sides that the effects of opium differ according to the size of the dose, and the frequency with which it is repeated.

Good results have been obtained from the use of arnica infusion in mania and melancholia. The tincture of arnica is exceptionally serviceable in delirium tremens, with depression.

In rheumatism and rheumatic gout, very decided curative effects are sometimes procured from arnica. The fact that it contains trimethylamine is probably the true explanation of its utility in these affections. It has also proved very efficacious in acute eczema, in erysipelas, and other cutaneous affections of gouty and rheumatic origin. Dysmenorrhoea of the congestive form, acute metritis, and other acute pelvic inflammations, are also favorably influenced by the administration of arnica.

The tincture of arnica has a popular reputation for the relief of sprains, bruises, and external inflammations. The author has known violent erysipelatous inflammation to follow its application to a sprained ankle. It is extremely doubtful whether the good effects are more decided than those of a spirit-lotion. The infusion or decoction does not, it is said, cause local irritation. Planat has demonstrated that arnica is a remarkably effective application to boils. He directs one part of the extract and two parts of honey to be thoroughly incorporated, and the paste spread on some adhesive plaster, leaving a margin to secure its adhesion to the skin. The plaster is renewed every twenty-four hours. To increase the effect, Planat gives by the stomach the tincture of arnica.

Authorities referred to:

Husemann, Dr. Theodor. Handbuch der gesammten Arzneimittellehre, zweiter Band, . p. 978.

Phillips, Dr. C. D. F. Materia Medica and Therapeutics, p. 305. Planat, Dr. Proprietés de l'Arnica. l'Abeille Médicale, 1880. In Annuaire de Thé-rapeutique, 1880.