Final answer:
Phenytoin is an anticonvulsant that works by stabilizing sodium channels to prevent neuronal hyperexcitability and seizures. While effective in treating epilepsy, neuropathic pain, and preventing digoxin-induced arrhythmias, it has side effects including nausea, dizziness, and potentially serious dental and dermatological conditions.
Step-by-step explanation:
Phenytoin's Mechanism of Action and Clinical Uses
Phenytoin is an anti-seizure medication (anticonvulsant) used primarily in the management of epilepsy. The mechanism of action of phenytoin includes the prolongation of the inactivation state of sodium channels, which stabilizes the threshold against hyperexcitability caused by excessive stimulation. This action prevents the repetitive and sustained firing of neurons, which is typical in seizures.
Side Effects of Phenytoin
Side effects associated with phenytoin can be quite varied, including central nervous system effects such as nystagmus, ataxia, dizziness, and somnolence. Gastrointestinal symptoms like nausea and vomiting may occur, as well as more serious effects like gingival hyperplasia, hematopoietic complications, and dermatological reactions. Overdosing can lead to severe neurological symptoms, and chronic use may cause peripheral neuropathy or osteomalacia.
Clinically, phenytoin's use is not limited to seizures; it can also be used for neuropathic pain and as an antiarrhythmic agent particularly in the treatment of digoxin-induced arrhythmias. Its pharmacokinetics necessitates regular monitoring to ensure therapeutic plasma concentrations are maintained and to avoid toxicity.