Belladonna should be avoided in people who have had significant reactions to belladonna or anticholinergic drugs, or who are allergic to belladonna or other members of the Solanaceae (nightshade) family such as bell peppers, potatoes, and eggplants. Long-term use of belladonna on the skin can lead to allergic rashes.
Side Effects and Warnings
In smaller doses, belladonna is traditionally thought to be safe, but may cause frequent side effects such as dilated pupils, blushing of the skin, dry mouth, rapid heartbeat, confusion, nervousness, and hallucinations. Based on animal study, belladonna alkaloids may inhibit cognitive function and gastrointestinal motility. High doses can cause death.
In children, death can be caused by a small amount of belladonna. Several reports of accidental belladonna overdose and death are reported. Belladonna overdose can also occur when it is applied to the skin. Belladonna overdose is highly dangerous and should be treated by qualified medical professionals. Because belladonna can slow the movement of food and drugs through the stomach and gut, the side effects may go on long after the belladonna is swallowed.
Belladonna may cause redness of the skin, flushing, dry skin, sun sensitivity, hives, and allergic rashes, even at dilute concentrations. A very serious, potentially life-threatening rash called Stevens-Johnson syndrome has been reported. Other side effects reported are headache, hyperactivity, nervousness, dizziness, lightheadedness, drowsiness or sedation, unsteady walking, confusion, slurred speech, exaggerated reflexes, or convulsions. The eyes may be sensitive to light and vision may be blurry. If pieces of belladonna are put into the eye, the pupils may be dilated permanently.
Cases report hyperventilation, coma with the loss of breathing, and severe high blood pressure. Others report abdominal fullness, difficult urination, decreased perspiration, slow release of breast milk while nursing, muscle cramps or spasms, and tremors. Belladonna should be avoided in those with difficulty passing urine, enlarged prostate, kidney stones, dry mouth, Sjögren syndrome, dry eyes, or glaucoma. Belladonna should be used cautiously with a fever. People with myasthenia gravis (a disorder of nerves and muscles) or Down's syndrome may be especially sensitive to belladonna.
Older adults and children should avoid belladonna, as there are many reports of serious effects in these age groups. Belladonna should not be combined with prescribed anticholinergic agents. People with heart disease, who have had a heart attack, fluid in the lungs, high blood pressure, or abnormal heart rhythms, should avoid belladonna. Because belladonna can affect the activity of the stomach and intestines, people who have had ulcers, reflux, hiatal hernia, obstruction of the bowel, poor movement of the intestines, constipation, colitis, or an ileostomy or colostomy after surgery should avoid belladonna.
Pregnancy and Breastfeeding
Belladonna is not recommended in pregnancy and breastfeeding because of the risks of side effects and poisoning. Belladonna is listed under category C according to the U.S. Food and Drug Administration (FDA) (category C includes drugs for which no thorough studies have been published). In nursing women who use belladonna, belladonna ingredients are found in breast milk, therefore endangering infants.
Adults (18 years and older)
A traditional dose of belladonna leaf powder is 50 to 100 milligrams taken by mouth, with a maximum single dose of 200 milligrams (0.6 milligrams of total alkaloids, calculated as the ingredient hyoscyamine) and a maximum daily dose of 600 milligrams. A traditional dose of belladonna root is 50 milligrams, with a maximum single dose of 100 milligrams (0.5 milligrams of total alkaloids, calculated as hyoscyamine) and a maximum daily dose of 300 milligrams. A traditional dose of belladonna extract is 10 milligrams, with a maximum single dose of 100 milligrams (0.5 milligrams of total alkaloids, calculated as hyoscyamine) and a maximum daily dose of 150 milligrams. The expert German panel, the Commission E, suggests these doses mainly for the treatment of "gastrointestinal spasm." For tincture of belladonna (composed of 27 to 33 milligrams of belladonna leaf alkaloids in 100 milliliters of alcohol), informal reports suggest either a total dose of 1.5 milligrams daily (divided into three doses daily with a double dose at bedtime) or a dose of 0.6 to 1 milliliters (0.18 to 0.3 milligrams of belladonna leaf alkaloids) taken 3-4 times daily.
For headache, studies have used the combination product Bellergal® (40 milligrams phenobarbital, 0.6 milligrams ergotamine tartrate, 0.2 milligrams levorotatory alkaloids of belladonna), taken by mouth twice daily.
Homeopathic doses often depend on the symptom being treated and the style of the prescribing provider. Dosing practices may therefore vary widely. Usually, a homeopathic product is diluted several times. For example, belladonna may be diluted by 100 (one teaspoon belladonna added to 99 teaspoons water) in the first round, and this new, dilute mixture may be diluted 30-fold (1 teaspoon of the dilute mixture added to 29 teaspoons water).
A belladonna plaster produced by Cuxson Gerrard (England) containing 0.25% belladonna alkaloids (hyoscine 2%, atropine 1%) has been used topically (applied to the skin) for muscle and bone aches. Long-term use may cause a rash at the site of the plaster.
Children (younger than 18 years)
Informal reports describe a typical dose of 0.03 milliliter for each kilogram of weight, taken by mouth three times daily. Another dose that has been used is 0.8 milliliter for each square meter of body surface area, taken by mouth three times daily (27 to 33 milligrams of belladonna leaf alkaloids in 100 milliliters). The maximum dose is reported as 3.5 milliliters in a day. Safety and effectiveness have not been proven.
Death in children may occur at 0.2 milligram of atropine for each kilogram of a child's weight. Since 2 milligrams of atropine are often found in a fruit, just two fruits may be deadly for a small child.
Homeopathic doses often depend on the symptom being treated and the style of the prescribing provider. Dosing practices may therefore vary widely. Usually, a homeopathic product is diluted several times.
Interactions with Drugs
Belladonna may slow the movement of food and medication through the gut, and therefore some medications may be absorbed more slowly. Many prescribed medications can interact with anticholinergic drugs that have similar effects to belladonna. A qualified healthcare professional, including a pharmacist, should be consulted prior to taking belladonna.
Atropine is an ingredient in belladonna. Theoretically, drugs that interact with atropine may also interact with belladonna. Some antidepressant medications (tricyclic drugs) can interact with belladonna. The effects of the drug cisapride, used to increase the movement of food through the stomach, may be blocked. Medications that can increase heart rate, especially procainamide, can cause an exaggerated increase in heart rate if given with belladonna. The use of alcohol with belladonna can cause extreme slowing of brain function.
Belladonna may also interact with alkaloids, atropine, ergot derivatives, hormonal agents, drugs that increase sun sensitivity, drugs cleared by the kidney, scopolamine, and tacrine (Cognex®).
Interactions with Herbs and Dietary Supplements
Belladonna may slow the movement of food and medication through the gut, and therefore some supplements may be absorbed more slowly. The use of belladonna with supplements that have anticholinergic activity, such as Jimson weed (Datura stramonium), may increase its effects and worsen its side effects.
Belladonna may also interact with alcohol, alkaloids, ergot derivatives, hormonal agents, and herbs and supplements that increase sun sensitivity or are cleared by the kidneys.