Products Affected - Description

Reason for the Shortage

• West-Ward discontinued their phenytoin in early-June, 2011 for business reasons since the company took over several Baxter products including phenytoin.^1,2
• Hospira has phenytoin on shortage due to increased demand for the product and manufacturing delays.³
• X-Gen Pharmaceuticals did not provide a reason for the shortage.⁴

Available Products

Estimated Resupply Dates

• Hospira has both phenytoin injection presentations on back order and the company estimates a release date of 2013.³
• X-Gen has phenytoin injection 50 mg/mL 2 mL vials available with an expiration date of December 2013. The company estimates additional product will be available in mid-May 2013.⁴

Implications for Patient Care

Phenytoin is labeled for the treatment or prevention of seizures occurring during neurosurgery and treatment of status epilepticus.⁵

Safety

• Phenytoin and fosphenytoin and are not equivalent in terms of dosing. However, fosphenytoin concentrations and dosing recommendations are expressed as phenytoin equivalents (PE) and orders for fosphenytoin should be written and dispensed as phenytoin equivalents. Fosphenytoin 75 mg/mL, also expressed as fosphenytoin 50 mg PE/mL, is equivalent to IV phenytoin 50 mg/mL.⁵
• Maximum administration rates differ for phenytoin and fosphenytoin. The maximum recommended phenytoin administration rate is 50 mg/minute in adults and 1-3 mg/kg/minute in neonates and pediatric patients. Fosphenytoin has a maximum administration rate of 150 mg PE/minute.^5,6
• Phenytoin injection is a vesicant and should be administered via a central line when possible.⁶ Rapid infusion can lead to cardiac or respiratory arrest. Continued administration through the same vein may increase risk of vascular injury or soft tissue damage.⁷ Use of a 20-gauge or larger IV catheter, infusion through a well-placed line in a vein no smaller than the antecubital fossa vein, and a reduced administration rate may decrease the risk of injuries.⁷ The dilution of phenytoin is controversial and is not recommended due to increased risk of phenytoin precipitation.^6,8

Alternative Agents & Management

• The choice of an alternative agent must be patient-specific and based on the clinical situation, venous access, renal and hepatic function, and other comorbid conditions.
• Use oral phenytoin whenever possible. If IV phenytoin is necessary, the same total daily dose can be given IV. Carefully monitor plasma phenytoin concentrations due to increased bioavailability with IV preparation.^5,6
• Table 1 provides some alternative treatment options for selected clinical situations.
• Table 2 provides some alternative treatment options for the treatment of status epilepticus or acute repetitive seizures in neonates, infants, and children.

Related Shortages

• Fosphenytoin Injection
• Mephobarbital Tablets— No Longer Available
• Phenobarbital Injection— Resolved

1. West-Ward (formerly Baxter), Customer Service (personal communication). March 2 and 29, April 25, May 18, June 15, July 18, August 23, September 20, October 25, 2011; November 3, 2011; January 3, February 10 and 28, March 13, May 4, June 14 and 29, August 22, October 12, December 7, 2012; January 16, February 26, March 14 and April 17, 2013.
2. West-Ward, Customer Service (personal communication). March 3 and 29, April 25, May 23, and June 16, 2011.
3. Hospira, Customer Service (personal communication). February 25, March 2 and 14, April 25, May 23, June 28, July 18, August 22, September 20, October 25, 2011, November 2, 2011; January 3, February 10 and 27, May 14, June 11, July 11, August 22, October 12, December 10, 2012; January 16, February 26, March 14, and April 17, 2013.
4. X-Gen, Customer Service (personal communication). November 8, 2011; February 29, May 14, June 5, July 13, August 22, October 12, December 10, 2012; January 16, February 26, March 14, and April 17, 2013.
5. Fosphenytoin Injection product information. Lake Forest, IL: Hospira; 2006 August.
6. Phenytoin Injection product information. Deerfield, IL: Baxter Healthcare Corporation; 2007 August.
7. Meek PD et al. Guidelines for nonemergency use of parenteral phenytoin products: proceedings of an expert panel consensus. Arch Intern Med. 1999;159:2639-2644.
8. McEvoy GK, Snow EK, Miller J, eds. AHFS 2010 Drug Information. Bethesda, MD: American Society of Health-System Pharmacists; 2010.
9. Aminoff MJ, Greenberg DA, Simon RR. Seizures and Syncope. In: Foltin J, Fernando N, eds. Clinical Neurology. 6^th edition. New York, NY: McGraw-Hill Companies, Inc.; 2005: 263-84.
10. Lexi-Comp Online. Hudson, OH: Lexi-Comp Inc.; 2010.
11. Rubin DH, Kornblau DH, Conway EE, Caplen SM. Neurological Disorders. In: Marx JA, Hockberger RS, Walls RM, et al, eds. Rosen’s Emergency Medicine: concepts and clinical practice. 7^th edition. Maryland Heights, MO: Mosby, Inc.; 2009. Accessed on May 28, 2010.
12. Trinka E. Emergency treatment of status epilepticus: what is the relative value of the standard anticonvulsants phenytoin, fosphenytoin, phenobarbital, valproate, and levetiracetam. Epilepsia. 2009;50:40-43.
13. Ruegg S, Naegelin Y, Hardmeier M, et al. Intravenous levetiracetam: treatment experience with the first 50 critically ill patients. Epilepsy Behav 2008;12(3):477–80.
14. Knake S, et al. Intravenous levetiracetam in the treatment of benzodiazepine refractory status epilepticus. J Neurol Neurosurg Psychiatry. 2008;79:588-589.
15. Milligan TA, Hurwitz A, Bromfield EB. Efficacy and tolerability of levetiracetam verus phenytoin after supratentorial neurosurgery. Neurology. 2008;71:665-669.
16. Szaflarski JP, Sangha KS, Lindsell CJ, Shutter LA. Prospective, randomized, single-blinded comparative trial of intravenous levetiracetam versus phenytoin for seizure prophylaxis. Neurocrit Care. 2010;12:165-172.
17. APP, Customer Service (personal communication). March 2, 2011.
18. American Regent, Customer Service (personal communication). March 3, 2011.
19. Bedford, Customer Service (personal communication). December 14, 2010.
20. Pediatric Lexi-Drugs Online. Hudson, OH: Lexi-Comp Inc.; 2010.
21. Abend NS, et al. Anticonvulsant medications in the pediatric emergency room and intensive care unit. Pediatric Emergency Care. 2008;24:705-18.
22. Phelps SJ, Hak EB, Crill CM, eds. Pediatric Injectable Drugs: The Teddy Bear Book. 9^th ed. Bethesda, MD: American Society of Health-System Pharmacists; 2010.
23. Young TE, Mangum B. Neofax 2009. 22^nd edition. Montvale, NJ: Thomson Reuters; 2009.
24. Custer JW, Rau RE, eds. The Harriet Lane Handbook. 18^th edition. Philadelphia, PA: Mosby-Elsevier, 2009.
25. Abend NS, Monk HM, Licht DJ, Dlugos DJ. Intravenous levetiracetam in critically ill children with status epilepticus or acute repetitive seizures. Pediatr Crit Care Med. 2009;10:505-10.
26. Gallentine WB, Hunnicutt AS, Husain AM. Levetiracetam in children with refractory status epilepticus. Epilepsy & Behavior. 2009;14:215-18.
27. Kirmani BF, Crisp ED, Kayani S, Rajab H. Role of intravenous levetiracetam in acute seizure management of children. Pediatr Neurol. 2009;41:37-39.
28. Goraya JS, et al. Intravenous levetiracetam in children with epilepsy. Pediatr Neurol. 2008;38:177-180.

Updated

Updated April 19, 2013 by Leslie Jensen, PharmD, Drug Information Specialist. Created March 3, 2011, by Michelle Wheeler, PharmD, Megan Dryer, PharmD, and M. Christina Beckwith, PharmD, Drug Information Specialists. Copyright 2012, Drug Information Service, University of Utah, Salt Lake City, UT.