⚡ PHENYTOIN 100 mg TABLET: DEFENDING THE BRAIN, STABILIZING SEIZURES ⚡

Trusted Antiepileptic Since 1938

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🔍 What Is Phenytoin 100 mg?

Phenytoin 100 mg is a widely prescribed antiepileptic drug (AED) used to prevent and control seizures. It is particularly effective for tonic-clonic (grand mal) seizures and focal (partial) seizures. Phenytoin helps maintain electrical stability in the brain, reducing the frequency and severity of epileptic episodes.

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⚙️ Mechanism of Action

Phenytoin works by blocking voltage-gated sodium channels in neurons. This action limits repetitive firing of neurons, which is critical in controlling seizure activity. By stabilizing overactive electrical signals, Phenytoin restores normal brain rhythms without causing general sedation.

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✅ Approved Uses

Phenytoin 100 mg tablets are indicated for:

• Tonic-Clonic (Grand Mal) Seizures

• Focal (Partial) Seizures

• Seizure prevention following head trauma or brain surgery

• Maintenance therapy after IV control of status epilepticus

• Occasionally used for certain arrhythmias (off-label)

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💊 Dosage and Administration

• Typical Adult Dose: 100 mg orally 3 times daily (total 300 mg/day)

• May be adjusted based on clinical response and blood levels

• Route: Oral; take consistently with or without food

📏 Therapeutic Plasma Level:

10–20 µg/mL — essential for effective seizure control and avoiding toxicity.

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🌟 Key Benefits

• Highly effective for long-term seizure prevention

• Well-established safety profile with decades of clinical use

• Cost-effective and available globally

• Long half-life allows convenient dosing schedule

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⚠️ Potential Side Effects

Common:

• Dizziness

• Drowsiness

• Nausea

• Ataxia (lack of coordination)

Long-Term or Serious:

• Gingival hyperplasia (gum overgrowth)

• Hirsutism (excessive hair growth)

• Vitamin D deficiency and bone issues

• Peripheral neuropathy

• Skin reactions (rash, Stevens-Johnson Syndrome)

• Liver toxicity or blood dyscrasias (rare)

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⚠️ Precautions and Warnings

• Narrow therapeutic index: small changes in dose or metabolism can cause toxicity

• Do not stop abruptly: risk of rebound seizures

• Use with caution in:

  • Liver disease

  • Elderly patients

  • Pregnant women (Risk of fetal hydantoin syndrome)

• May require folic acid or vitamin D supplementation

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🔄 Drug Interactions

Phenytoin is a potent enzyme inducer, meaning it affects the metabolism of many drugs:

• ↓ Effectiveness of oral contraceptives

• Alters effects of warfarin, cyclosporine, theophylline

• Interacts with other AEDs like valproate and carbamazepine

• Alcohol impacts levels (acute ↑ / chronic ↓)

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🧪 Monitoring Guidelines

• Plasma drug levels

• Liver function tests

• Complete blood count (CBC)

• Dental check-ups for gum health

• Bone density in long-term use

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🧠 Conclusion

Phenytoin 100 mg tablet is a cornerstone in the management of epilepsy, providing reliable, long-term seizure control. Its affordability, efficacy, and versatility make it an essential part of antiepileptic therapy—though careful monitoring is crucial due to its narrow therapeutic window and extensive drug interactions.