First of all, it is worth knowing that phenytoin is a substance derived from hydantoin, with anticonvulsant and antiarrhythmic properties. Phenytoin is given for status epilepsy. Its action prevents convulsions after neurosurgical procedures and head injuries. It has also found its application in acute cardiac arrhythmias, in poisoning with digitalis glycosides. It is also used after a heart attack, in cardiac surgery and general anesthesia.
The drug is administered to patients during cardiac catheterization and electrical defibrillation. Phenytoin is a substance that is poorly soluble in water. Therefore, the absorption of substances from the gastrointestinal tract is variable and amounts to 30-97 percent. If you take the medicine with a meal, it will be better absorbed. Phenytoin is metabolized in our liver. It is mostly an inactive metabolite which is excreted by the kidneys. Interestingly, about 2 percent of the drug is excreted by the patient in the urine. It is worth knowing that part of the population is genetically unable to cope with the metabolism of phenytoin. About 90 percent of the dose of the drug is bound to plasma proteins. The dosage of phenytoin is individualized for the patient. The dose is determined by measuring the level of phenytoin in the blood. It is worth realizing that phenytoin is a substance with a low therapeutic index, and thus – it is easy to overdose.
Side effects
Phenytoin, like all medicines, can cause side effects. One example is problems with the circulatory system, such as arrhythmias or megaloblastic anemia. Nausea, vomiting, and gastrointestinal disturbances can also be another side effect. There may be headaches, dizziness, visual disturbances, and seizures in the event of an overdose. Another example is gum growth. Just this discomfort can be minimized by taking care of oral hygiene. It is also worth knowing that phenytoin reacts with other drugs. So, for example, when taking oral contraceptives, phenytoin reduces the duration of their action. It is also worth remembering that pregnant and breastfeeding women should avoid phenytoin.
Phenytoin as a component of drugs
Phenytoin is also an ingredient in drugs. One such example is Epanutin Parenteral, a solution for injection, which is an anticonvulsant and antiarrhythmic drug. If the patient is hypersensitive to any component of the preparation or to other hydantoin derivatives, he should not take this drug. The drug should also be discontinued in the presence of second and third degree sinoatrial block. Contraindication is also sinus bradycardia, Adams-Stokes syndrome. The drug should not be used in parallel with delavirdine. The solution is not intended for intra-arterial administration.