Obat Fenitoin

Summary

This presentation provides an in-depth overview of Phenytoin, an anticonvulsant drug used to treat seizures, including generalized tonic-clonic and focal seizures in epilepsy patients. The speaker discusses its therapeutic effects, which stabilize neuronal membranes to reduce seizure activity. It also covers common adverse effects such as gingival hyperplasia, acne, skin rashes, and osteomalacia. Dosage recommendations are provided based on body weight and age, and the process of Phenytoin synthesis is explained. Lastly, the presentation highlights the drug's mechanism of action involving the stabilization of voltage-gated sodium channels to control neuronal firing and prevent seizures.

Takeaways

• 😀 Phenytoin is an anticonvulsant used to prevent and manage tonic-clonic and focal seizures in epilepsy patients.
• 😀 Phenytoin stabilizes neuronal membranes, reducing seizure activity in the motor cortex.
• 😀 Common side effects of phenytoin include gingival hypertrophy (gum swelling), acne, skin rashes, and hypersensitivity reactions.
• 😀 Phenytoin may cause megaloblastic anemia by interfering with folate absorption.
• 😀 Long-term use of phenytoin can lead to hyperglycemia by inhibiting insulin release.
• 😀 Osteomalacia is another side effect, as phenytoin disrupts calcium metabolism and affects vitamin D sensitivity.
• 😀 The initial oral dose of phenytoin is 3-4 mg/kg body weight per day (150-300 mg), with a maintenance dose of 300-400 mg/day.
• 😀 The maximum daily dose of phenytoin is 600 mg, with pediatric doses ranging from 5-8 mg/kg body weight per day.
• 😀 Phenytoin is synthesized through the condensation of benzaldehyde with vitamin B1, followed by reactions involving FeCl3, H+, and urea.
• 😀 Phenytoin works by inhibiting voltage-gated sodium channels, preventing further depolarization and controlling seizures.

Q & A

What is phenytoin and what is its primary use?

Phenytoin is an anticonvulsant medication primarily used to prevent and control seizures, including generalized tonic-clonic and focal seizures in patients with epilepsy.

How does phenytoin work in the body to prevent seizures?

Phenytoin works by stabilizing the neuronal membranes, reducing excessive neuronal activity, and inhibiting sodium channels, which helps prevent the spread of seizure activity in the brain.

What are some common adverse effects of phenytoin?

Common adverse effects of phenytoin include gingival hypertrophy (swelling of gums), acne, skin rashes, megaloblastic anemia (due to folate absorption interference), hyperglycemia, and osteomalacia (bone softening due to calcium metabolism disruption).

What is the typical dosing regimen for phenytoin in adults?

For adults, the initial dose of phenytoin is typically 3-4 mg per kg of body weight per day or 150-300 mg per day, which can be divided into two doses. The usual maintenance dose ranges from 300-400 mg per day, with a maximum of 600 mg per day.

How is phenytoin synthesized?

Phenytoin is synthesized through a multi-step process that starts with benzaldehyde reacting with vitamin B1 to form benzoin. Then, ferric chloride (FeCl3) and H+ ions are used to convert it into phenylhydantoin. Finally, urea is introduced to form phenytoin.

Why does phenytoin cause gingival hypertrophy (gum swelling)?

Phenytoin can cause gingival hypertrophy due to its effect on fibroblast activity, leading to excessive growth of gum tissue, especially in individuals who use the medication for long periods.

What is the role of sodium channels in phenytoin's mechanism of action?

Phenytoin affects sodium channels by inhibiting their rapid return to a resting state after activation. This prevents excessive sodium influx into neurons, stabilizing the electrical activity in the brain and reducing the likelihood of seizures.

How does phenytoin affect blood sugar levels?

Phenytoin can interfere with insulin release, which may result in hyperglycemia (high blood sugar). This effect is particularly important for diabetic patients or those at risk of developing diabetes.

What is the impact of phenytoin on bone health?

Phenytoin may lead to osteomalacia, a condition in which the bones become softened and weakened due to impaired calcium absorption and disrupted vitamin D metabolism.

What are the risks associated with high doses of phenytoin?

High doses of phenytoin can lead to toxicity, increasing the risk of adverse effects such as severe skin reactions, cardiovascular issues, or nerve damage. It is crucial to monitor blood levels to avoid reaching toxic concentrations.