MASSACHUSETTS GENERAL HOSPITAL

Department of Pharmacy

Department of Nursing

Critical Care

Generic Name:

Phenytoin

Trade Name:

Dilantin

Action:

Anticonvulsant

Indications:

  • Tonic-clonic and psychomotor seizures; status epilepticus
  • Seizures secondary to preeclampsia and eclampsia
  • Seizure prophylaxis

Administration Guidelines:

Usual Dosage Range and Route:

*IV push/infuse at a rate no greater than 50 mg/ minute*

*Administration through a large bore IV is recommended*

PROPHYLAXIS Loading Dose: 15-20mg/kg (1000mg).

STATUS EPILEPTICUS or ACTIVE SEIZURE Loading dose: 18-20mg/kg (MAXIMUM = 25-30mg/kg)

*LOADING DOSE IS USUALLY GIVEN PRIOR TO STARTING MAINTENANCE*

Maintenance Dose: 100 mg IVP three to four times daily.

RN IV push approved for doses =300mg

Standard Concentration:

***These concentrations are not programmed in the pump libraries, rates must be manually calculated and entered***

Microinfusion pump: 1000mg/20ml (50mg/ml)

1g/100ml 0.9% NaCl, stable for 2 hours only (0.22 micron in-line filter required)

Special Considerations:

Accurate history, including a serum phenytoin concentration should be considered when determining loading dose

Administer undiluted IV Push doses through a patent IV of normal saline or flush pre and post with normal saline. Incompatible with dextrose solutions (do not mix or co-administer with D5W).

Do not administer as a continuous infusion.

0.22 micron in-line filter required for diluted drug.

Cardiac monitor is necessary during administration of loading dose.

Avoid administration via hand, wrist or foot. Use best access site possible (large bore vein). If unavailable, consider oral route, or another agent.

Assessment of IV site is critical, particularly with the alkaline pH of Phenytoin. Avoid infusing Phenytoin via IV in the hand, wrist or foot.

 

In the event of an infiltration, shut infusion off and notify physician. Attempt to aspirate as much infiltrated drug as possible from the IV catheter. Elevate the limb and apply heat to area to reduce soft tissue damage.

Dosage adjustments may be required in hepatic, cardiac, or renal disease.

Monitor serum albumin levels.

Levels drawn after loading doses should be taken at least 60 minutes after the IV loading dose has been administered.

Obtain Free Phenytoin Concentrations in patients with hypoalbuminemia, renal failure, or hepatic impairment. The following equations may be used if a free level is unavailable:

Calculating phenytoin level correction in hypoalbuminemia:

Corrected level= Measured phenytoin level /[(albumin x 0.2) + 0.1]

In renal failure: CrCL < 20

Corrected level= Measured phenytoin level /[(albumin x 0.1) + 0.1]

Precautions and Side Effects:

  • Hypotension, bradycardia and EKG changes
  • Severe thrombophlebitis (Purple Glove Syndrome)
  • CNS depression (nystagmus, somnolence, ataxia)