Management of Phenytoin Administration

• Clear colourless solution 50 mg/ml in 2 ml ampoules.
• Contains propylene glycol 0.4 ml/ml, ethanol 0.1 ml/ml.
• pH 10–12.3.

• Flavoured syrup 30 mg/5 ml. Preservative sodium benzoate 5 mg/ml.
• Note: there is a Dilantin Forte Suspension containing phenytoin 100mg/5ml

• Loading doses are charted in mg/dose on stat page of prescription chart.
• Maintenance doses are charted on prescription chart in mg/dose.

Administration

Slow IV Infusion (Avoid administration via central lines)

1. Dilute immediately prior to use to 5 mg/ml by adding to sodium chloride 0.9% ⁵. Use our usual dilution method. No other diluent is acceptable.
2. Use a Pall 0.2 micron in-line filter during administration.
3. Administer at a rate not faster than 1.0 mg/kg/minute ⁶ using a syringe pump. Diluted solution must be administered within one hour of preparation ⁵. Observe diluted solution for the formation of crystals.
4. Flush line with sodium chloride 0.9% before and after administration of phenytoin.
5. Do NOT mix with other drugs, IV solutions, blood or blood products.

1. Enteral feeding decreases the absorption of oral phenytoin. Do not give oral feeds for 30 minutes before and after phenytoin dose. Give oral dose with water to increase absorption ⁶.
2. As oral phenytoin tends to adhere to the PVC tubing, flush naso-gastric tube with 2ml of water after administration.

Observation and Documentation

1. Monitor for adverse effects.
2. Assess for signs of toxicity.
3. Monitor BP closely. ECG monitor during intravenous therapy.
4. Assess for and document any seizure activity.
5. Observe administration site closely. Extravasation may cause tissue inflammation and necrosis.

Storage

• IV preparation: Store below 25°C. Protect from light
• Oral preparation:  Follow manufacturers guidelines

Selected References