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Adverse Drug Reactions: “What’s Your Reaction?”
Cross Sensitivity Between Sulfonamides and Silver Sulfadiazine
Tanya John, PharmD, Senior Attending Pharmacist, MGH and Colleen Collins, RPh, Senior Attending Pharmacist, MGH
Volume XIII, Issue 10

Adverse drug reactions (ADRs) are a major clinical issue which can prolong hospitalization and increase overall healthcare costs.¹ JCAHO requires hospitals to have a concurrent ADR monitoring system in place.

The American Society of Health-System Pharmacists (ASHP) defines a significant ADR as “any unexpected, unintended, undesired, or excessive response to a drug that:

• Requires discontinuing the drug
• Requires changing the drug therapy
• Requires modifying the dose
• Necessitates admission to a hospital
• Prolongs stay in a health care facility
• Necessitates supportive treatment
• Significantly complicates diagnosis
• Negatively affects prognosis, or
• Results in temporary or permanent harm, disability or death”.²

The ADR program at MGH relies upon reporting from health professionals at this institution.  It is a vital part of our hospital’s quality improvement process, which strives to constantly improve patient safety.   Compliance with ADR reporting identifies ADRs that should be reported to the FDA for post-marketing reports and also tracks ADRs that can be avoided or prevented with changes in practice.

Drug Therapy will be featuring potentially avoidable examples of ADRs from MGH in this and upcoming issues for education purposes.

Case:

A patient who had experienced rash and urticaria to sulfonamides in the past received silver sulfadiazine cream for wound care.  An hour after the cream was applied to the patient’s legs, the patient experienced urticaria on the neck and abdomen.  The cream was washed off the legs with soap and water and the patient received diphenhydramine, ranitidine, and hydrocortisone with relief of the patient’s symptoms.

Silver sulfadiazine is commonly used to prevent and treat infection in second- and third-degree burns.  This anti-infective cream is produced by the reaction of silver nitrate with sulfadiazine, with a mechanism of action that appears to be distinct from that of its separate components.  Although little silver is absorbed, sulfadiazine may be systemically absorbed in therapeutic levels from the site of application, in particular when applied to large body surface areas with burns.³  Thus, adverse reactions characteristic of sulfonamides can occur, although cutaneous reactions such as maculopapular rash are generally rare (2-5%) and are mostly absent in medical literature.^3,4  A 1985 case report by Y. Sawada observed a similar reaction to our case in a patient who had been treated topically with silver sulfadiazine for burns, who later received oral sulfamethoxazole-trimethoprim for UTI.  The patient presented with a total body rash, to which immunology tests showed positive reactions to both drugs.⁵

“Here’s Our Reaction”:

• There is potential cross-sensitivity between silver sulfadiazine and other sulfonamides, as silver sulfadiazine contains a sulfa moiety. ³
• All allergy orders should also be entered into the CAS system.  In this case, remember to add silver sulfadiazine to the patient’s allergy profile after a reaction of this nature.
• All medication orders should be entered appropriately in the CAS system, i.e., not under General Care orders but under Medication orders, so that appropriate checking mechanisms (allergies, drug/drug interactions, drug/food interactions) can be applied.
• If no other therapeutic alternative is available for a patient with allergies, an allergy consult may be warranted.

Ultimately, ADR reporting will lead to positive patient outcomes.

Report ADRs by:

• paging your floor pharmacist
• filing an incident report
• calling the ADR hotline at 6-1575.

Selected References:

1. Lazarou J, Pomeranz BH, Corey PN.  Incidence of adverse drug reactions in hospitalized patients.  JAMA.  1998; 279:1200-1205.
2. American Society of Health-System Pharmacists.  ASHP Guidelines on Adverse Drug Reaction Monitoring and Reporting.  Am J Health-Syst Pharm.  1995;52:417-9.
3. McEvoy GK, ed. AHFS Drug Information 2000.  Bethesda, MD:  American Society of Health-System Pharmacists, Inc.  2000: 3219-20.
4. McKenna SR, Latenser BA, Jones LM, et al.  Serious silver sulphadiazine and mafenide acetate dermatitis.  Burns. 1995; 21: 310-2.
5. Sawada Y.  Adverse reaction to sulphonamides in a burned patient – a case report.  Burns Incl Therm Inj.  1985;12(2):127-31.