Digoxin is a type of medication used to help treat heart conditions such as irregular heart beat and congestive heart failure. The medication is derived from the digitalis plant, more commonly known as Foxglove. Although the medicine is extremely beneficial in those with such conditions, too much digoxin can be fatal. Digoxin toxicity is especially dangerous in children and the elderly. In cases of overdose, an antidote for digoxin called "digoxin immune fab" can be used to slow or reverse the effects.
Digoxin immune fab was developed specifically to work as a digoxin antitdote, and is only meant to be used in extreme cases. The medication is made by injecting sheep with a compound similar to digoxin. The sheep develop antibodies against the foreign invader, and those antibodies are harvested from the animals' blood. The injected sheep are kept apart from other sheep to ensure that their blood remains healthy.
Signs that a chronic overdose may be occurring and the antidote may be required include vomiting, visual disturbances, fast or slow heart rate, uneven heartbeats, confusion, hallucinations, and loss of consciousness. Some patients suffer from a rare yet serious skin rash called Stevens-Johnson syndrome, which causes skin to blister painfully before shedding off, sometimes in large sheet-like chunks. These symptoms are usually more obvious in younger patients. A digoxin overdose may be more difficult to diagnose in the elderly.
In addition to being given the antidote, patients suffering from digoxin toxicity are given other forms of treatment to help alleviate its effects. Most patients are put on intravenous fluids to help restore their electrolyte balance, and their stomachs may be pumped if the digoxin dose was recently taken. In extreme cases, patients are put on kidney dialysis to cleanse the blood. Diagnostic tests include blood tests and an electrocardiogram (EKG) are used to determine the extent of the damage and monitor the progress of the antidote.
Side effects from a digoxin antidote primarily occur as a result of withdrawal from the digoxin itself rather than from the digoxin immune fab. These include rapid heartbeat, congestive heart failure, and dangerously low potassium levels, also known as hypokalemia. Digoxin immune fab may cause allergic reactions in patients who suffer from antibiotic allergies, and should not be used in those allergic to papaya, as enzymes from the fruit are used in the creation of this antidote for digoxin to break down the antibodies into specific fragments; some of these enzymes may be left behind after manufacturing.