💉 Phenytoin Injection 25 mg/mL
📌 1. Prescription / Indications:
Phenytoin injection is primarily used for:
- Status epilepticus (acute seizure emergency)
- Seizure prophylaxis post-neurosurgery or head trauma
- Second-line therapy after benzodiazepines in convulsive seizures
- When oral route is not feasible
📄 2. Description:
- Form: Sterile injectable solution
- Strength: 25 mg phenytoin sodium per 1 mL
- Route: IV (preferred), IM (rarely, due to erratic absorption)
- Appearance: Clear, colorless to faintly yellow solution
- pH: Alkaline (10–12), requiring slow IV administration
🔬 3. Nature / Drug Class:
- Category: Antiepileptic / Anticonvulsant
- Class: Hydantoin derivative
- Mechanism of Action:
- Stabilizes neuronal membranes
- Inhibits repetitive firing by blocking voltage-gated sodium channels
🌟 4. Advantages:
- Rapid onset for emergency seizure control
- Long half-life allows less frequent dosing
- IV administration is vital in unconscious or non-cooperative patients
- Can maintain therapeutic phenytoin levels during acute crises
📦 5. Common Packaging:
| Form | Volume | Container |
|---|---|---|
| Ampoule or vial | 2 mL, 5 mL | Amber glass vial |
| Multidose vial (rare) | 10 mL | Preservative added |
🧊 6. Storage Conditions:
- Store at 15–30°C
- Protect from light
- Do not refrigerate (precipitation risk)
- Use immediately once opened; discard unused portion
⚠️ 7. Special IV Administration Advice:
- Dilute in NS only (NOT dextrose — precipitation occurs)
- Infusion rate: max 50 mg/min (adults)
- Slower in elderly or cardiac patients
- Use in-line filter (0.22 micron)
- Monitor:
- ECG
- Blood pressure
- Respiratory status
👩⚕️ 8. Patient Advice / Precautions:
- Must be given by trained personnel
- May cause:
- Arrhythmias
- Hypotension
- Tissue necrosis (extravasation → purple glove syndrome)
- Long-term monitoring: liver function, serum levels (target: 10–20 µg/mL)