The leaves and root of Atropa Belladonna, a perennial plant, native of Great Britain, and cultivated in this country. Belladonna contains two alkaloids: bel-iadonine, of no special importance; and atropine, the active principle, to which the medicinal and poisonous properties of the drug are owing.
Alone or in a watery solution belladonna (or atropine) is not absorbed by the skin, but when combined with alcohol, glycerin, or camphor, it is readily so absorbed, and even more quickly by mucous membranes and inflamed surfaces; so that physiological symptoms, from the first slight dryness of the throat to evidence of severe poisoning, may be produced by external applications.
Used in this way, belladonna acts upon the ends of the sensory nerves as an anaesthetic, relieving pain, as is seen in the action of belladonna plasters. This sedative power, exerted over the nerves which control the sweat glands, produces the familiar effect of drying up the secretion of milk and checking the action of the skin.
Taken internally, belladonna enters the blood and reaches the tissues with rapidity; and in the case of atropine alone absorption is even more quickly accomplished. Elimination takes place by the urine, and quickly, atropine appearing unchanged in from ten to twenty hours.
The stimulant and tonic powers of belladonna, which are very strong, are exerted over the whole sympathetic system and unstriped or involuntary muscular fibre; and its sedative, anodyne actions are directed toward the motor system. It is a mydriatic, dilating the pupils; an anti-spasmodic, and the most important respiratory stimulant known, keeping up the activity of the respiratory centre while at the same time allaying the irritability of the respiratory nerves.
It has but little control over severe pain, and is not, strictly speaking, an hypnotic, though it sometimes acts as one indirectly by removing conditions which prevented sleep. It has a peculiar effect on the brain, causing excitability, and in large doses narcotism.
As a cardiac stimulant it weakens the force of the inhibitory apparatus, derived from the cerebro-spinal system, which retards the heart; and promotes the activity of the accelerator apparatus, derived from the sympathetic system, which excites the heart.
The secretion of saliva is checked by belladonna, and this causes a dryness of the mouth and throat which is diagnostic and is watched for as one of the first signs of constitutional impression.
When small doses of belladonna or atropine are given, the respirations become deeper and more frequent. The pulse, at first slowed for a short time, afterwards becomes strong and rapid, its rapidity being somewhat out of proportion to the rate of the respirations.
After full doses it may rise as high as twice its former number of beats. The small vessels are more energetically contracted, and with the impetus to the circulation the temperature rises 1/2° or 1°. The pupils are dilated and vision disordered; the face flushed; the mouth and throat are dry; the tongue is red; swallowing is difficult, thirst is present, and a feeling as of sore throat.
With larger doses the flush becomes a uniform bright red, and resembles the rash of scarlet-fever, except that it is not punctated.1 It spreads first over face and neck, extending perhaps over the whole body, and is due to a reaction and paralysis of the vaso-motor nerves following the primary stimulation.
1 Having the appearance of being formed by exceedingly minute dots or points of red.
The pupils are bright and widely staring. Headache and vertigo, restlessness, illusions, and delirium appear. The delirium of belladonna is of a peculiarly active, talkative, busy type, accompanied frequently by laughter and gayety and associated with physical lassitude. The patient is sometimes absorbed with spectral illusions and visions, without showing any fear. Occasionally he becomes furious, quarrelsome, and maniacal.
With larger poisonous doses there is loss of muscular power, beginning in the lower extremities and becoming complete. Sensation is not lost. With excessive poisonous doses convulsions may appear, and shortly before death stupor and paralysis develop, and the temperature becomes subnormal. The urine, at first increased, diminishes and may be entirely suppressed. Death results from asphyxia, from the failure of the respiratory organs, and there is heart failure as well.
The smallest fatal dose is not positively known. Alarming symptoms have been produced by gr. 1/20-1/10 of atropine, and death in fatal cases has occurred as early as five hours after taking the poison.
The first necessity is to use emetics or the stomach-pump. The bladder must be emptied at regular intervals to prevent re-absorption. Tannic acid is given and external heat, mustard baths, hot and cold affusions to the head, and artificial respiration used.
Medicinal doses sometimes produce mild delirium, or a feeling of thirst and feverishness. The local application of the drug to the eye sometimes causes an inflammation on the face about the eyelids. The rash of belladonna may appear after small doses, and may desquamate; and a bluish color may be noticed on the lips. The dryness of the throat is always to be looked for.
Average dose, xii.-0.75 mil.
Average dose, gr. 1/4-0.015 Gm.
Average dose, i-0.05 mil.
Contains 30% of extract of belladonna leaves. There is also a 10% ointment of belladonna.