Foxglove (Digitalis purpurea) was introduced to North America from Europe. It is easily recognised by its numerous tubular flowers, arranged on a spike and varied in colour by species. Foxglove contains digitalis, a cardiac glycoside prescribed by doctors to treat cardiovascular disease. Digitalis is extremely poisonous however, and care should be taken to keep foxglove out of reach of pets and children, who may be poisoned.
In 1775, an English physician named William Withering discovered that the digitalis in foxglove was the active ingredient in a recipe for treatment of dropsy. After 10 years of trials, including studies on 12 children, Withering published his classical account of the herb, "An Account of the Foxglove and its Medicinal Uses; With Practical Remarks on Dropsy and Other Diseases". Today, digitalis is commonly prescribed to strengthen and regulate the heartbeat, especially in patients with congestive heart failure.
Foxglove is a biannual that blooms from June through September and reaches a height of 2 to 4 feet. Its leaves produce a rosette the first year and a flower spike the second. Foxglove flowers are long and tubular. Colors range from purple and pink to yellow and white, depending on the species. The plant is common in gardens and has been naturalised in the Pacific Northwest. It is often found along roads, in dry pastures, and in granite walls.
Digitalis poisoning is a serious problem, especially among very young or very old populations. In 1985, the American Association of Poison Control Centers (AAPCC) reported that 80 per cent of digitalis poisoning in toddlers occurred when children found and ingested grandparents' medication. Digitalis toxicity can also result from exposure to the plant itself; the flowers, leaves and seeds are all poisonous. Toxicity can also occur from inhaling the smoke of burning plants.
The effects of digitalis poisoning in children (as well as adults) may not appear immediately after exposure, sometimes occurring up to several hours later. The most common effects are nausea and vomiting, drowsiness, headache and confusion. Acute poisoning is usually obvious, but chronic toxicity often manifests more subtly, for example as a change in vision. According to Dr. Kown, Director of Pediatric Emergency Medicine and Associate Clinical Professor at the University of California at Irvine Medical Center, the most common causes of digitalis toxicity in children are erroneous dosing and accidental ingestion.
Preventions and Precautions
Because digitalis poisoning in children is most often unintentional, toxicity in young children can be effectively prevented by child-proofing the home environment. This includes making sure that all medications are closed securely and out of reach of young children. Foxglove plants, if kept inside, should also be kept where they will not be accidentally ingested. Watch young children outdoors to ensure they do not accidentally come into contact with foxglove.