Diphedan Suspension

Indications

Parenteral phenytoin is used to treat generalized tonic-clonic seizures, as well as the prevention and treatment of seizures that occur during neurosurgery. Oral phenytoin can be replaced with intravenous phenytoin for short-term use. When oral phenytoin administration is not possible, parenteral phenytoin should be used.

Pharmacology

Phenytoin works as an anticonvulsant by increasing efflux or decreasing the influx of sodium ions across cell membranes in the motor cortex during nerve impulse generation, thereby stabilizing neuronal membranes and reducing seizure activity. It works as an antiarrhythmic by prolonging the effective refractory period and inhibiting the automaticity of the ventricular pacemaker.

Administration & Dosage

It's best if you take it with food. Do not administer feeds 2 hours before or after a dose to patients on nasogastric or other enteral feeds. Feeding times should be consistent throughout therapy. Switching dosage forms/brands without thinking about it is not a good idea.

Epilepsy: Oral
Adults: Start with 3-4 mg/kg per day in a single dose or divided doses. Alternatively, if necessary, start with 150-300 mg per day and gradually increase to 600 mg per day. 200-500 mg per day for maintenance.
Initially, 5 mg/kg per day, divided into 2-3 doses. 4-8 mg/kg per day in divided doses for maintenance. The maximum daily dose is 300 mg.

Interaction

The effects of other sedatives or ethanol may be amplified. Increases the toxicity of paracetamol and lithium. Acetazolamide raises the risk of osteomalacia. Acyclovir, antineoplastics, benzodiazepines, ciprofloxacin, CYP2C9 inducers (e.g. carbamazepine), CYP2C19 inducers (e.g. rifampin), folic acid, and vigabatrin all reduced serum levels/effects.

Contraindications

Patients with a history of hypersensitivity to phenytoin, its inactive ingredients, or other hydantoins should not take phenytoin sodium.
Because of the effect of parenteral phenytoin on ventricular automaticity, sinus bradycardia, sino-atrial block, second and third-degree A-V block, and Adams-Stokes syndrome can occur.
A history of phenytoin-related acute hepatotoxicity in the past.

Side Effect

Hypersensitivity, loss of appetite, headache, dizziness, tremor, transient nervousness, insomnia, GI disturbances (e.g. nausea, vomiting, constipation), gum tenderness and hyperplasia, acne, hirsutism, coarsening of facial features, rashes, and osteomalacia

Pregnancy & Lactation

Although there is evidence of human fetal risk, the benefits of use in pregnant women may outweigh the risk (e.g., if the drug is needed in a life-threatening situation or for a serious disease for which safer drugs cannot be used or are ineffective).

Precautions & Warnings

DM; hepatic impairment; hypoalbuminemia; porphyria; seizures (may increase the frequency of petit mal seizures); debilitated patients; elderly. Cardiovascular disease, e.g. sinus bradycardia, heart blocks; DM; hepatic impairment; hypoalbuminemia; porphyria; seizures (may increase the frequency of petit mal seizures). In hypotension, heart failure, or MI, use caution when administering IV medications, and keep a close eye on your blood pressure and ECG during treatment. IV administration should be done slowly to avoid hypotension, CNS depression, and cardiac arrhythmias.

Storage Conditions

Keep the temperature below 15-30°C and away from light and moisture. Keep out of children's reach.