Difenin

Difenin, also known by its international nonproprietary name Phenytoin, is a drug widely used in neurology for the treatment and prevention of certain types of seizures and epilepsy. Phenytoin belongs to a class of medications known as anticonvulsants or antiepileptic drugs.

Phenytoin stabilizes the threshold activity of neurons in the brain, limiting the excessive propagation of nerve signal that can lead to seizures. It works by slowing down sodium channels in nerve cells, which helps reduce the activity in the brain needed to trigger a seizure episode.

適應症 The pennies

1. Epilepsy: Diphenine is commonly used to prevent various types of seizures, including generalized tonic-clonic seizures, partial seizures, and other forms of epilepsy.
2. Migraines: In some cases, Diphenine may be used as a prophylactic agent to reduce the frequency and severity of migraines.
3. Cardiac arrhythmias: Phenytoin is sometimes used to treat certain types of cardiac arrhythmias.
4. Tremor: Diphenine can be used to reduce tremors in patients with various neurological diseases, such as Parkinson's disease.
5. Trigeminal neuralgia: In rare cases, Diphenine may be prescribed to treat trigeminal neuralgia, although this is not the most common use.

發布表單

1. Tablets: Diphenin is usually available as an oral tablet. Tablets may have different dosage depending on the specific medical purpose.
2. Solution: Sometimes Difenin can be supplied as a solution for oral administration. The solution can be used in cases where the tablets cannot be swallowed or if a more accurate dosage is required.
3. Injection solution: Difenin can also be presented in the form of a solution for injection, which is used for rapid introduction of the medicinal substance into the body. This type of release form is usually used in situations where a rapid onset of action is required or when it is impossible to take medication by mouth.

藥效學

1. Blocking native sodium channels: Phenytoin blocks the restoration of native sodium channels, which prevents neurons from re-firing and reduces their excitability.
2. Reducing neuronal excitability: This mechanism of action prevents the occurrence and propagation of epileptic discharges in the brain.
3. Prevention of epileptic seizures: Phenytoin is used as a prophylactic agent to prevent the development of various types of epileptic seizures, including partial and generalized ones.
4. Antiarrhythmic effect: In addition to its antiepileptic effects, phenytoin may also have an antiarrhythmic effect through inhibition of cardiac sodium channel activity.
5. Additional effects: In some cases, phenytoin may also exhibit anxiolytic and muscle relaxant properties, which may be useful in the treatment of certain other conditions such as anxiety disorders and spasticity.

藥代動力學

1. Absorption: Phenytoin can be administered either orally or intravenously. When taken orally, absorption of phenytoin occurs in the upper gastrointestinal tract, mainly in the duodenum. The rate and extent of absorption may vary depending on the drug and the individual patient.
2. Distribution: Phenytoin is highly bound to plasma proteins, mainly albumin. This factor may affect the distribution of phenytoin in tissues and its pharmacological activity.
3. Metabolism: Phenytoin is metabolized in the liver, where the main metabolites are hydroxylated phenytoin (5-(4-hydroxyphenyl)-5-phenylhydantoin) and phenytoic acid. Phenytoin metabolism can occur through several routes, including hydroxylation, glucuronidation and aromatic ring oxidation.
4. Excretion: Phenytoin is eliminated primarily through the kidneys. In patients with normal renal function, the elimination half-life of phenytoin is approximately 22 hours, but may be prolonged in patients with impaired renal function.

劑量和管理

1. Method of application:

   • Tablets: Tablets are usually taken orally, that is, by mouth. They should be swallowed whole with water. Do not break, chew or crush the tablets unless indicated in the instructions.
   • Solution: Diphenin solution can be taken orally. Dosage should be measured using the provided dropper or measuring cup.
   • Injection solution: Diphenin injection solution is administered intravenously by medical personnel.

2. Dosage:

   • Difenin dosage can vary greatly depending on the patient's specific medical condition.
   • The dosage usually starts low and is gradually increased under the supervision of a physician until the optimal therapeutic effect is achieved.
   • The usual starting dose for adults is 100 mg 2-3 times a day. However, this may vary depending on the patient's response to the medication and the nature of the disease.
   • Children may be given a lower dose depending on their age and weight.

在懷孕期間使用 The pennies

Phenytoin (Diphenyne) use during pregnancy is associated with certain risks and potential complications. Here are some important findings from the studies:

1. Teratogenic effects: Phenytoin is classified as a potentially teratogenic substance, especially when taken in the early stages of pregnancy. Research shows an increased risk of birth defects such as cleft lip and/or palate, heart defects, and minor anomalies in newborns (Monson et al., 1973).
2. Fetal hydantoin syndrome: Children exposed to phenytoin in utero may exhibit features of fetal hydantoin syndrome, which includes craniofacial anomalies, microcephaly, mental retardation, and other physical and developmental disorders (Gladstone et al., 1992).
li>
3. Immunological reactions: Phenytoin can also cause immunological reactions, including allergic reactions, which can potentially be worsened during pregnancy (Silverman et al., 1988).

Due to these risks, the use of phenytoin during pregnancy requires close medical supervision. Doctors usually recommend carefully weighing the potential risks and benefits of this medication, especially if it is used to control epilepsy, where the risk of seizures may also harm the mother and baby.

禁忌

1. Hypersensitivity: People with known hypersensitivity to phenytoin or other components of the drug should not use Diphenin.
2. Porphyria: Diphenine is contraindicated in the presence of porphyria, a rare inherited metabolic disorder that may be aggravated by phenytoin.
3. Atrioventricular block: Patients with atrioventricular block (impaired conduction of electrical impulses in the heart) should avoid the use of Diphenin, as it may increase this effect.
4. Wolff-Parkinson-White syndrome: Patients with Wolff-Parkinson-White syndrome (an atrial syndrome that can lead to a fast heart rate) should avoid using Diphenine.
5. Liver failure: Patients with liver failure should use Diphenine with caution as it is metabolized in the liver. Dosage may need to be adjusted depending on the degree of liver damage.
6. Pregnancy and breast-feeding: Diphenine may be contraindicated for use during pregnancy and breast-feeding. The physician must evaluate the potential risks and benefits of its use in each specific case.
7. Other Medical Conditions: People with other serious medical conditions, such as cardiac arrhythmias, blood disorders, mental disorders, etc., should discuss the use of Diphenin with a doctor before starting treatment.

副作用 The pennies

1. Drowsiness and dizziness: These are some of the most common side effects of diphenine. They can affect your ability to drive and perform other tasks that require concentration.
2. Unsteady motor coordination: Patients may experience clumsiness or difficulty coordinating movements.
3. Feeling unwell: Some people may feel tired or generally unwell.
4. Memory impairment: Diphenine may affect short-term and long-term memory.
5. Increased blood pressure: Some patients may experience increased blood pressure.
6. Hair loss: Diphenine may cause hair loss in some people.
7. Digestive disorders: Stomach upset, nausea, vomiting, or changes in appetite may occur.
8. Allergic reactions: In rare cases, allergic reactions such as hives, itching or swelling may occur.
9. Decreased white blood cell count: Diphenine may decrease the number of white blood cells, making the body more vulnerable to infection.
10. Osteopenia: Long-term use of diphenine may lead to osteopenia or decreased bone density.

過量

1. Heart disorders: Include arrhythmia, tachycardia and even heart failure.
2. Central nervous system: The appearance of drowsiness, depression, convulsions, decreased consciousness and coma.
3. Respiratory failure: Respiratory depression or respiratory arrest may develop.
4. Gastrointestinal disorders: Possible nausea, vomiting, diarrhea and other gastrointestinal disorders.
5. Metabolic disturbances: Changes in electrolyte levels (eg, hypernatremia), metabolic acidosis, or alkaline imbalance may occur.
6. Other complications: Include allergic reactions, skin rashes, fever and other unusual reactions.

與其他藥物的相互作用

1. Pharmacokinetic interactions: Phenytoin may affect the metabolism and concentrations of other drugs by inducing cytochrome P450 enzymes in the liver. This may cause other drugs to be metabolized more quickly and reduce their effectiveness. These drugs include warfarin, carbamazepine, lamotrigine, digoxin, etc.
2. Pharmacodynamic interactions: Phenytoin may enhance or decrease the effects of other drugs, such as central depressants (eg, alcohol, sedatives, antidepressants) or drugs that depress the central nervous system.
3. Plasma level interactions: Phenytoin may compete with other drugs for binding to plasma proteins, which may result in an increase in the free plasma fraction of the other drug and an increase in its effect.
4. Electrolyte Interactions: Phenytoin may cause hyperglycemia and hypomagnesemia, which may also affect the action of other drugs, especially those that affect glucose and magnesium levels in the body.