What is Amantadine Poisoning?

Amantadine poisoning is an acute condition caused by an overdose of amantadine, a drug which is used to treat some viruses, especially influenza, along with Parkinson's Disease. This condition attracted a great deal of popular attention in 2008, when it was featured in the television series House. While there is no treatment for amantadine poisoning, there are some supportive therapies which can be used to make the patient more comfortable, and sometimes the effects can be reversed if the condition is caught early enough.

This drug is an anticholinergic, which means that it interferes with acetylcholine, a neurotransmitter which plays a critical role in the central nervous system. The way in which amantadine works against viruses and Parkinson's Disease is not fully understood, but it has been proven effective. Even at the recommended dose, amantadine comes with some dangerous side-effects, including suicidal behavior and a variety of central nervous system problems like anxiety, shaking, and blurred vision. It is also dangerous to withdraw amantadine rapidly: patients must be tapered off the drug.

If someone takes too much amantadine, he or she can get amantadine poisoning, characterized by heart arrhythmia, respiratory distress, and pulmonary edema, in which the lungs fill with fluid. The drug also overloads the liver and kidneys, which can lead to urine retention. In the instance of a single overdose, accidental or not, stomach pumping can sometimes prevent the seizures and eventual coma associated with amantadine poisoning, but when a patient has overdosed over an extended period of time, the condition can be much harder to treat.

Supportive therapies include the use of a ventilator to help the patient breathe, and administration of fluids through intravenous needles. Physostigmine, a drug which is used to treat a variety of anticholinergic overdoses, can sometimes also help with this poisoning. In the case of the famous House episode, the patient was doomed because her kidneys were already in failure before the onset of poisoning, but amantadine poisoning is not necessarily always fatal.

Prevention of amantadine poisoning involves taking only the recommended dose, and providing the prescribing doctor with a list of medications in use, along with medical problems. The use of amantadine is contraindicated in people with liver and kidney problems or a history of seizures, and mixing certain medications with amantadine can be a very bad idea. When seeking medical treatment for any condition, including a case of suspected poisoning, being able to provide medical personnel with a list of medications in use and their dosages can be critical.