Immunologic tolerability profile of celecoxib

Antibiotic prophylaxis in immunosuppressed patients - Missed opportunities from trimethoprim-sulfamethoxazole allergy label

Trimethoprim-sulfamethoxazole (TMP-SMX) is a broad spectrum antibiotic in use for more than 50 years. It has an important indication as first line agent in the prophylaxis of opportunistic infections, particularly Pneumocystis jirovecii pneumonia (PJP), in immunosuppressed patients. For those who have a history of allergy or severe intolerance to TMP-SMX, pentamidine, dapsone or atovaquone may be substituted; however there is evidence that TMP-SMX offers superior coverage for PJP, toxoplasmosis, and nocardiosis. Compared to pentamidine, it has the added benefit of cost-effectiveness and self-administration as opposed to required hospital attendance for administration. Many patients who report a history of allergy or adverse reaction to TMP-SMX (or "sulfur allergy") will be found not to be allergic; and even those who are allergic may be able to be desensitized. The evaluation and, where appropriate, removal of TMP-SMX allergy label enables the use of TMP-SMX for prophylaxis against opportunistic infections. This is a cost-effective intervention to optimize antimicrobial prescribing and reduce the risk of opportunistic infections in immunosuppressed patients.

Oral acetazolamide for intraocular pressure lowering: balancing efficacy and safety in ophthalmic practice

Introduction: Systemic acetazolamide is an efficacious adjunct to topical therapy to lower intraocular pressure (IOP) in glaucomatous eyes. This article aims to provide a comprehensive review for how best to use the agent in ophthalmic practice.Areas covered: This article will review the history, mechanism of action, methods of observing efficacy, indications for IOP lowering, side effects, allergy information including discussion of limited cross-reactivity between antimicrobial and non-antimicrobial sulfonamides, formulations, dosing and monitoring of acetazolamide. To select articles for this review, an electronic search was conducted using the PubMed database and cross-referencing was conducted for relevant literature.Expert opinion: The benefits of oral carbonic anhydrase inhibitor therapy can outweigh the risks in many circumstances. It is important that eye care practitioners work together with a patient's primary care practitioner to monitor for and mitigate risks. Greater education is needed with regard to the allergy profile of these powerful agents. Though not often a first-line option, oral carbonic anhydrase inhibitors remain pivotal and play in important role in delivery of eye care.

Sulfonamide Drug Allergy

PURPOSE OF REVIEW

We sought to review past and current literature on sulfonamide drug allergy and distill it in a practical manner to assist the clinician, specifically focusing on cross-reactivity and desensitization.

RECENT FINDINGS

There do not appear to be consistent genetic markers to reliably predict features of or the presence hypersensitivity reactions. Recent evidence continues to alleviate early concerns cross-reactivity between sulfonamide antibiotics and non-antibiotics. Sulfonamide drug allergy is frequently encountered by the practicing clinician. For sulfonamide antibiotics, delayed rash is the most common clinical manifestation. There is no current evidence to support avoidance of all non-antibiotic sulfonamides in those with a reported allergy to sulfonamide antibiotics, although certain scenarios require caution. Available evidence supports the cautious reintroduction of sulfonamide antibiotics via desensitization, which is usually well tolerated and should be considered in those with strong indications for trimethoprim-sulfamethoxazole and a reported sulfonamide allergy.

Clinical analysis of HIV/AIDS patients with drug eruption in Yunnan, China

Drug eruption is the most common clinical presentation in patients with HIV/AIDS. The systemic clinical and risk factors associated with drug eruption remain unknown. A retrospective analysis in HIV/AIDS patients with drug eruption was carried out with demographic data, epidemiological data, clinical characteristics, laboratory data and follow-up data. The risk factors correlated with prognosis were assessed by case control analysis. A total of 134 out of 1817 HIV/AIDS patients (7.4%) presented drug eruptions. The major class of sensitizing drug was HAART drugs (47.7%), followed by antibiotics (47.0%). Nevirapine (39.6%) was the most common sensitizing drug in the HAART regimens. The patients received HAART or had allergic history were prone to develop drug eruption. The alanine aminotransferase, albumin, globulin, creatinine, blood urea nitrogen (BUN), lymphocytes, red blood cells (RBC) and eosinophils of the drug eruption patients were significantly different the control patients. The allergic history, opportunistic infection, viral load, CD4 cell count, high globulin and low albumin were the risk factors correlated with death in HIV/AIDS patients with drug eruption. It is proposed that patients with higher viral loads, higher globulin levels and lower white blood cells (WBC) should be given special attention for the prevention of complications and death.

An evidence-based approach for providing cautionary recommendations to sulfonamide-allergic patients and determining cross-reactivity among sulfonamide-containing medications

WHAT IS KNOWN AND OBJECTIVE

Prescribing sulfonamide-containing medications for patients with sulfonamide allergy continues to complicate medical decisions. We examined the cautionary recommendations in the approved drug monographs and primary literature, and formulated an evidence-based grading of cautionary recommendations for sulfonamide allergy and cross-reactivity among sulfonamide-containing medications.

METHODS

Drug monographs were collected from six countries and three drug compendia. Two reviewers independently extracted the data from the contraindication, warning and/or precaution sections of drug monographs. Evidence for cross-reactivity was examined in the primary literature and compared with drug monograph recommendations. Consequently, medications were categorized based on the strength of recommendation and level of evidence by consensus.

RESULTS AND DISCUSSION

We identified wide variability in cautionary recommendations ranging from no warning or precaution to contraindication among the sources reviewed. The recommendations were located mainly in the contraindication section of monographs for France (65·2%), United Kingdom (51·9%), Italy (50·0%), South Korea (43·5%), United States (38·2%) and Canada (37·0%), whereas in drug compendia, the recommendations were found in the precaution section for Martindale (51·4%) and Micromedex-Drugdex (33·3%), and contraindication and precaution section for the American Hospital Formulary Service Drug Information 2010 (30·8%). Evidence from the primary literature varied with recommendation included in drug monographs. Evidence-based categorization was carried out for 16 medications. Two sulfonamide-moiety-containing drugs were considered safe, six non-sulfonylarylamines required precaution, and eight medications from all three sulfonamide chemical classes were considered mostly unsafe.

WHAT IS NEW AND CONCLUSION

There are significant discrepancies in cautionary recommendations included in drug-labels and drug compendia. Statements concerning cross-reactive hypersensitivity with other sulfonamides generally suggest theoretical possibilities. The consensus evidence-based grading instrument developed may be useful for deriving cautionary recommendations for sulfonamide-allergic patients.

Review of the selective COX-2 inhibitors celecoxib and rofecoxib: focus on clinical aspects

The selective cyclooxygenase-2 (COX-2) inhibitors celecoxib and rofecoxib were designed to have similar efficacy but less gastrointestinal toxicity than traditional nonsteroidal anti-inflammatory drugs (NSAIDs). Their efficacy has been demonstrated in the treatment of osteoarthritis, rheumatoid arthritis, ankylosing spondylitis, postoperative dental pain and dysmenorrhea. These agents produce fewer endoscopic ulcers, symptomatic ulcers and gastrointestinal bleeds than traditional NSAIDs; although the absolute benefit is small and the gastropreserving effect is negated by concurrent use of low-dose aspirin for cardiovascular risk reduction. Nephrotoxicity and hyptertension remain concerns with COX-2 inhibitors, as they are with traditional NSAIDs. COX-2 inhibitors may be safe alternatives to traditional NSAIDs for patients with aspirin-sensitive asthma.

Drug allergy: an updated practice parameter

Adverse drug reactions (ADRs) result in major health problems in the United States in both the inpatient and outpatient setting. ADRs are broadly categorized into predictable (type A and unpredictable (type B) reactions. Predictable reactions are usually dose dependent, are related to the known pharmacologic actions of the drug, and occur in otherwise healthy individuals, They are estimated to comprise approximately 80% of all ADRs. Unpredictable are generally dose independent, are unrelated to the pharmacologic actions of the drug, and occur only in susceptible individuals. Unpredictable reactions are subdivided into drug intolerance, drug idiosyncrasy, drug allergy, and pseudoallergic reactions. Both type A and B reactions may be influenced by genetic predisposition of the patient

Knowledge and attitudes of American pharmacists concerning sulfonamide allergy cross-reactivity

OBJECTIVE

Pharmacists are commonly confronted with patients with a history of sulfonamide allergy. Basic immunologic and clinical data suggest a low likelihood of a patient with a history of sulfonamide hypersensitivity developing an allergic reaction to a non-antimicrobial sulfonamide drug. We conducted a survey to describe the knowledge and attitudes of licensed pharmacists concerning sulfonamide allergy cross-reactivity.

METHODS

A survey instrument was developed and sent to all licensed pharmacists in the state of Iowa. The survey recorded demographic information and included six patient scenarios designed to elicit responses concerning sulfonamide allergy cross-reactivity with a number of non-antimicrobial sulfonamides.

RESULTS

A total of 421 surveys were returned for a 39% response rate. There was a wide discrepancy in approaches to patients with a history of sulfonamide allergy prescribed a sulfonamide containing non-antibiotic. Differences depended on previous history of tolerating the medication in question, the degree of cautionary statements in product literature, and the familiarity the pharmacist had with the product.

CONCLUSION

Our survey suggests a significant diversity in knowledge and attitudes of pharmacists concerning cross-reactivity of sulfonamide antimicrobials and other drugs with a sulfonamide moiety. Depth of training in this area may be an associative factor.

Allergies to sulfonamide antibiotics and sulfur-containing drugs

OBJECTIVE

To provide a literature review and clinical summary of the evaluation and management of sulfonamide drug reactions.

DATA SOURCES

Published English-language medical literature.

STUDY SELECTION

Selected trials of drug desensitization protocols.

RESULTS

Obtaining a detailed history is invaluable in assessing a history of reactions to sulfonamide medications, because allergy to these drugs remains a clinical diagnosis at present. Numerous efficacious drug desensitization protocols for management have been published and are reviewed in detail.

CONCLUSIONS

The term sulfa allergy is imprecise and misleading and therefore should be discouraged. There are important distinctions between sulfonylarylamines (antimicrobial sulfonamides), nonarylamine (nonantimicrobial) sulfonamides, and sulfones, with regard to allergic and other adverse drug reactions. Most reactions to sulfonylarylamines probably result from multifactorial immunologic and toxic metabolic mechanisms, whereas less is known about the precise mechanisms of reactions to other sulfur-containing drugs.

Sulfonamide allergy and cross-reactivity

Concerns about cross-allergenicity between sulfonamide antibiotics and nonantibiotic sulfonamide-containing drugs continue to complicate pharmacotherapy. Several elegant investigations have demonstrated unequivocal lack of interaction between the sulfonamide group and either cellular or humoral immunity. The immunologic determinant of type I immunologic responses to sulfonamide antibiotics is the N1 heterocyclic ring, and nonantibiotic sulfonamides lack this structural feature. Many non-type I hypersensitivity responses to sulfonamide antibiotics are attributable to reactive metabolites that cause either direct cytotoxicity or humoral or cellular responses. Metabolite formation is stereospecific to the N4 amino nitrogen of the sulfonamide antibiotics, a structure not found on any nonantibiotic sulfonamide drugs. Cellular immune responses to sulfonamide antibiotics are responsible for many non-immunoglobulin E-mediated dermatologic reactions; however, the stereospecificity of T-cell response renders cross-reactivity between sulfonamide antibiotics and nonantibiotics highly unlikely. Apparent cross-reactivity responses to sulfonamide-containing drugs likely represent multiple concurrent, rather than linked, drug hypersensitivities.

Drug hypersensitivity

Allergic drug reactions compose a small percentage of ADRs, yet they are commonly encountered in clinical practice, and physicians are taught routinely to question patients about these reactions during history taking. Among antibiotics, the immunochemistry of penicillins has been elucidated,leading to the development of validated skin test reagents to diagnose type 1 allergy. Currently, the temporary commercial unavailability of Pre-Pen makes accurate penicillin skin testing impossible; however, this important skin test reagent is expected to become available sometime in 2006. Type 1 allergies to most other drugs lack comparable diagnostic tests, and their diagnosis is therefore driven by the patient's history. When readministration of medications to which patients report previous reactions is indicated, it may be almost always successfully accomplished by means of either graded challenge or desensitization.

Clinical implications of cyclo-oxygenase-2 inhibitors for acute dental pain management: benefits and risks

BACKGROUND; Cyclo-oxygenase-2 inhibitors (COX-2i) demonstrate analgesic efficacy for patients who require gastrointestinal safety. The authors discuss the potential benefits and risks of these novel, but expensive, analgesics when used in dentistry.

METHODS

The authors conducted a MEDLINE search focused on the subject headings of common analgesic drugs and COX-2i, using peer-reviewed journals limited to the English language. They selected for review 127 articles that met the criteria. They also tried to identify any randomized controlled trials pertinent to dentistry and indicative of evidence-based medicine. RESULTS. When comparing COX isoforms (COX-1 and COX-2), the authors found that overlapping and mutually exclusively properties coexist. COX-2i originally were developed to minimize interference with the gastroprotective properties of the COX-1 isoform, while selectively preventing prostanoid synthesis expressed solely at sites of bodily trauma or other inflammation. COX-2i were found to provide pain relief equal to or slightly exceeding that offered by many mild narcotics. They may avoid some of the serious side effects that can occur with even short-term use of nonselective nonsteroidal anti-inflammatory drugs.

CONCLUSIONS

The pharmacodynamics of COX-2i reveal an agent that includes analgesic, anti-inflammatory and gastroprotective properties but also allows for an undesirable disruption of the delicate hemodynamic balance.

CLINICAL IMPLICATIONS

Symptomatic and asymptomatic gastroparietic patients who do not have severe cardiovascular, cerebral or renal ischemic disease benefit from use of COX-2i. Long-term use of these agents in medically compromised patients may prove disastrous.

Need for common internal controls when assessing the relative efficacy of pharmacologic agents using a meta-analytic approach: case study of cyclooxygenase 2-selective inhibitors for the treatment of osteoarthritis

OBJECTIVE

To evaluate the role of common internal controls in a meta-analysis of the relative efficacy of cyclooxygenase 2-selective inhibitors (coxibs) in the treatment of osteoarthritis (OA).

METHODS

A systematic search of Medline and US Food and Drug Administration electronic databases was performed to identify randomized, placebo-controlled clinical trials of coxibs (etoricoxib, celecoxib, rofecoxib, valdecoxib) in patients with hip and/or knee OA. The effect size for coxibs and common active internal controls (nonsteroidal antiinflammatory drugs [NSAIDs], naproxen) were determined by the mean changes from baseline in Western Ontario and McMaster Universities Osteoarthritis Index pain subscores as compared with placebo.

RESULTS

The effect size for all coxib groups combined (0.44) indicated greater efficacy as compared with placebo, but significant heterogeneity (P < 0.0001) was observed. Rofecoxib at dosages of 12.5 mg/day and 25 mg/day and etoricoxib at a dosage of 60 mg/day had similar effect sizes (0.68 and 0.73, respectively), but these effect sizes were comparatively greater than those for both celecoxib at dosages of 200 mg/day and 100 mg twice daily or valdecoxib at a dosage of 10 mg/day (0.26 and 0.16, respectively). The effect sizes for NSAIDs or naproxen versus placebo, as determined using data from rofecoxib/etoricoxib trials, were consistently higher than the effect sizes derived from trials of celecoxib/valdecoxib. Significant heterogeneity was present in the overall effect size for NSAIDs (P = 0.007) and naproxen (P = 0.04) groups based on data available from all coxib trials.

CONCLUSION

Coxibs and common active internal controls showed larger effect sizes versus placebo in the rofecoxib/etoricoxib trials than in the celecoxib/valdecoxib trials. These findings suggest systematic differences among published coxib trials and emphasize the need for direct-comparison trials. In the absence of such trials, common internal controls should be assessed when performing indirect meta-analytic comparisons.

Tolerability of selective cyclooxygenase inhibitor, celecoxib, in patients with analgesic intolerance

Intolerance reactions to acetyl salicylic acid (ASA) and nonsteroidal anti-inflammatory drugs (NSAIDs) are common and caused by inhibition of COX-1 enzyme. Therefore, drugs that selectively inhibit COX-2 enzyme may be safe in these subjects. In this study, we evaluated the tolerability of celecoxib, a selective COX-2 inhibitor, in patients with analgesic intolerance. The eligible study population consisted of patients with a history of urticaria/angioedema, naso-ocular symptoms, bronchospasm, and/or anaphylactoid reaction induced by ASA and/or NSAIDs. A single-blind, placebo-controlled oral challenge test was performed in the hospital setting. On 2 separate days, 1/4 and 3/4 divided doses of placebo and celecoxib (Celebrex 200 mg, Pfizer, Turkey) were given with 2-hour intervals. Seventy-five subjects (mean age: 38.2 +/- 1.4 years; F:M: 55:20) were included in the study. Twenty-one subjects had asthma. No reaction was observed with placebo or celecoxib provocation. Although celecoxib seems to be a safe alternative drug in our study group, considering its serious adverse events reported in the literature, the drug should be recommended for patients with analgesic intolerance only after being tested by an experienced allergist.

Sulfonamide Cross-Reactivity: Fact or Fiction?

OBJECTIVE:

To provide a critical and comprehensive review of the literature, specifically case reports and observational studies used to support the concept of cross-reactivity between sulfonylarylamines and non-sulfonylarylamines.

DATA SOURCES:

A list of medications was formulated from several different review articles. A MEDLINE/PubMed search was conducted (1966–March 2004) using the individual medications and the MeSH terms of drug hypersensitivity/etiology, sulfonamides/adverse effects, and/or cross-reaction.

STUDY SELECTION AND DATA EXTRACTION:

A critical review of the methodology and conclusions for each article found in the search was conducted. The manufacturer's package insert (MPI) for each drug was examined for a statement concerning possible cross-reactivity in patients with a sulfonamide allergy. If indicated, the manufacturers were contacted to obtain any clinical data supporting the statement.

DATA SYNTHESIS:

A total of 33 medications were identified. Seventeen (51.5%) of the MPIs contained statements of varying degrees concerning use in patients with a “sulfonamide” allergy; 21 case series, case reports, and other articles were found.

CONCLUSIONS:

After a thorough critique of the literature, it appears that the dogma of sulfonylarylamine cross-reactivity with non-sulfonylarylamines is not supported by the data. While many of the case reports on the surface support the concept of cross-reactivity, on closer examination the level of evidence in many of the cases does not conclusively support either a connection or an association between the observed cause and effect.

Risk:benefit ratio of nonsteroidal anti-inflammatory drugs in systemic lupus erythematosus

Nearly 80% of patients with systemic lupus erythematosus (SLE) are treated with NSAIDs for fever, arthritis, serositis and headaches. This article reviews currently available literature on non-selective and selective inhibitors of cyclooxygenases, with an emphasis on the efficacy and safety profile reported in SLE patients. All NSAIDs, regardless of their cyclooxygenase selectivity, induced renal side effects including sodium retention and reduction in glomerular filtration rate. In addition, lupus nephritis is a risk factor for NSAID-induced acute renal failure. NSAID-induced hepatotoxicity is increased in SLE patients in addition to cutaneous and allergic reactions. Finally, aseptic meningitis has been reported more frequently in NSAID-treated SLE patients. Nevertheless, NSAIDs can safely be prescribed to most lupus patients provided that their administration is re-evaluated on a regular basis and the patient is closely monitored.

Drug desensitization

Although most patients who report a history of drug allergy are not truly allergic, this article focuses on those individuals with confirmed drug hypersensitivity. Desensitization is an immunologic method that allows allergic patients to receive the sensitizing drug safely. Classically, the procedure is applied in IgE-mediated reactions, but its use has been extended to other drug reactions. The most common clinical scenarios wherein desensitization may be needed are reviewed. The discussion includes rapid desensitization of patients with IgE-mediated allergies to penicillin and other classes of antibiotics, and sulfonamide desensitization of HIV-positive patients.

Cross-reactivity among p-amino group compounds in sulfonamide fixed drug eruption: diagnostic value of patch testing

We studied 28 patients with fixed drug eruption (FDE) caused by sulfonamide antibiotics to investigate cross-reactivity between sulfonamide derivatives and p-amino compounds and to explore the usefulness of patch testing, as an alternative to controlled oral challenge testing (COCT), in diagnosis within this clinical area. COCT with sulfamethoxazole (SMX), sulfadiazine (SDZ), sulfamethizole (SMZ), furosemide (FU), procaine (PRO) and glipizide (GPZ) was performed. Patch testing (PT) with SMX and SDZ was carried out. In all patients, the diagnosis of FDE was confirmed by positive COCT and allergy to trimethoprim ruled out by COCT. 42.8 and 31.8% of the SMX-induced FDE patients reacted to SMZ and SDZ, respectively. All patients (n = 28) tolerated FU, PRO and GPZ. COCT performed with the 3 sulfonamide antibiotics in 12 patients was positive in 2 subjects with the 3 drugs, in 2 patients only with SMX and SMZ and in the remaining 8, SMX was the only causative drug. PT was positive in 5 of 25 patients positive on COCT. The probability of obtaining a positive PT was higher among patients who had a residual lesion than that among those who lacked this. Cross-reactivity between different sulfonamide antibiotics is thus variable, being most likely between SMX and SMZ. We have found no cross-reactivity between sulfonamide antibiotics and other sulfonamide derivatives or p-amino drugs in FDE. PT is a useful tool in the diagnosis of FDE, especially if there are residual lesions, because it avoided the need for COCT in 20% of patients.

Presumed "sulfa allergy" in patients with intracranial hypertension treated with acetazolamide or furosemide: cross-reactivity, myth or reality?

PURPOSE

To determine whether acetazolamide or furosemide produce allergic cross-reactions in patients with self-reported "sulfa allergy."

DESIGN

Retrospective case series.

METHODS

A retrospective review included patients with intracranial hypertension and a self-reported sulfa allergy treated with either acetazolamide or furosemide seen at the University of Iowa Hospitals and Clinics from 1972 to 2003. All presumed medication-related side effects were collected, including both predictable adverse effects (for example, paresthesias, fatigue) and unpredictable adverse reactions (for example, cutaneous fixed eruptions, urticaria, Stevens-Johnson syndrome, toxic epidermal necrolysis, angioedema, anaphylaxis).

RESULTS

We reviewed 363 charts. Of these, 329 patients (91%) were excluded. Of the remaining 34 cases that did report a so-called sulfa allergy, 13 (38%) received acetazolamide alone, 7 (21%) received furosemide alone, and 14 (41%) received both acetazolamide and furosemide. Of the 27 patients who received acetazolamide, 10 (37%) had no documented allergic cross-reaction to sulfa, and 2 (7%) cases had urticaria. The remaining 15 (56%) of acetazolamide-treated patients experienced predictable adverse reactions for this drug (for example, paresthesias). No patient experienced a severe allergic cross-reaction to sulfa. Of 21 patients who received furosemide, no unpredictable adverse reactions or allergic cross-reactions to sulfa were noted.

CONCLUSIONS

We find little clinical or pharmacological evidence to suggest that a self-reported sulfa allergy is likely to produce a life-threatening cross-reaction with acetazolamide or furosemide. These medications should be considered for intracranial hypertension if the risk-to-benefit ratio warrants their use.

Likelihood and Mechanisms of Cross-Allergenicity Between Sulfonamide Antibiotics and Other Drugs Containing a Sulfonamide Functional Group

Concerns about cross-allergenicity between sulfonamide antibiotics and nonantibiotic, sulfonamide-containing drugs persist and can complicate patients' drug therapy unnecessarily. No interaction between the human immune system and the sulfonamide functional group has been demonstrated. The immunologic determinant of type I, immediate hypersensitivity responses to sulfonamide antibiotics is the N1 heterocyclic ring. Nonantibiotic sulfonamides do not contain this structural feature. Non-type I hypersensitivity responses to sulfonamide antibiotics are largely attributable to reactive metabolites that may cause either direct cytotoxicity or immunologic response. Formation of these metabolites is a stereospecific process that occurs at the N4 amino nitrogen of the sulfonamide antibiotics, a structure also not found on any nonantibiotic sulfonamide drugs. The stereospecificity of these reactions implies that cross-reactivity with nonantibiotic sulfonamide-containing drugs is highly unlikely; this assertion is supported by recent literature. However, T-cell recognition of unmetabolized, nonhaptenated parent sulfonamide antibiotic appears to occur in a small subset of hypersensitive patients. Several of the severe cutaneous reactions associated with sulfonamide antibiotics are mediated by T cells. It is not known whether T-cell recognition of antibiotic is related to the sulfonamide functional group. Until the mechanism of this recognition is elucidated, cross-reactivity with nonantibiotic sulfonamides appears to remain at least theoretically possible.

Absence of cross-reactivity between sulfonamide antibiotics and sulfonamide nonantibiotics

BACKGROUND

The safety of sulfonamide nonantibiotics is unclear in patients with prior allergic reactions to sulfonamide antibiotics.

METHODS

We conducted a retrospective cohort study using the General Practice Research Database in the United Kingdom, examining the risk of allergic reactions within 30 days after the receipt of a sulfonamide nonantibiotic. Patients with evidence of prior hypersensitivity after the receipt of a sulfonamide antibiotic were compared with those without such evidence. Similar analyses were also performed with the use of penicillins instead of sulfonamides, to determine whether any risk was specific to sulfonamide cross-reactivity.

RESULTS

Of 969 patients with an allergic reaction after a sulfonamide antibiotic, 96 (9.9 percent) had an allergic reaction after subsequently receiving a sulfonamide nonantibiotic. Of 19,257 who had no allergic reaction after a sulfonamide antibiotic, 315 (1.6 percent) had an allergic reaction after receiving a sulfonamide nonantibiotic (adjusted odds ratio, 2.8; 95 percent confidence interval, 2.1 to 3.7). However, the risk of allergic reactions was even greater after the receipt of a penicillin among patients with a prior hypersensitivity reaction to a sulfonamide antibiotic, as compared with patients with no such history (adjusted odds ratio, 3.9; 95 percent confidence interval, 3.5 to 4.3). Furthermore, among those with a prior hypersensitivity reaction after the receipt of a sulfonamide antibiotic, the risk of an allergic reaction after the subsequent receipt of a sulfonamide nonantibiotic was lower than the risk of an allergic reaction after the subsequent receipt of a penicillin (adjusted odds ratio, 0.7; 95 percent confidence interval, 0.5 to 0.9). Finally, the risk of an allergic reaction after the receipt of a sulfonamide nonantibiotic was lower among patients with a history of hypersensitivity to sulfonamide antibiotics than among patients with a history of hypersensitivity to penicillins (adjusted odds ratio, 0.6; 95 percent confidence interval, 0.5 to 0.8).

CONCLUSIONS

There is an association between hypersensitivity after the receipt of sulfonamide antibiotics and a subsequent allergic reaction after the receipt of a sulfonamide nonantibiotic, but this association appears to be due to a predisposition to allergic reactions rather than to cross-reactivity with sulfonamide-based drugs.

Valdecoxib-induced toxic epidermal necrolysis in a patient allergic to sulfa drugs

A 55-year-old Caucasian woman with a previously documented sulfa allergy was admitted to the hospital after she developed toxic epidermal necrolysis; she had been taking valdecoxib for 8 days for knee pain. Four days later, her bullous lesions had progressed to 45-50% of her body surface area. She was transferred to a burn unit for aggressive wound care and fluid hydration. Valdecoxib, a cyclooxygenase-2 inhibitor, is a benzenesulfonamide prescribed for arthritis pain and inflammation, and dysmenorrhea. Clinicians should exercise caution when prescribing valdecoxib to patients who are allergic to sulfa drugs.

Toxic epidermal necrolysis after celecoxib therapy

Toxic epidermal necrolysis (TEN) is a rare disease that is defined by extensive detachment of full-thickness epidermis. It most often is related to an adverse drug reaction. The drugs implicated in most cases of TEN have been sulfonamides, anticonvulsants, allopurinol, and some of the conventional nonsteroidal antiinflammatory agents. We describe a patient who developed a generalized desquamating rash after therapy with celecoxib.

Celecoxib for systemic lupus erythematosus: case series and literature review of the use of NSAIDs in SLE

The primary objectives of this study were to evaluate the safety and efficacy of the cyclooxygenase-2 inhibitor celecoxib in systemic lupus erythematosus (SLE) patients both with and without a self-reported sulfa drug allergy and to review the literature on the use of nonsteroidal agents in SLE subjects. A retrospective review of medical records was performed for 50 SLE patients seen by a community-based rheumatologist and treated with open label celecoxib in doses of 200-400 mg/day for a period of 1-9 months. A MEDLINE search of all articles pertaining to the use of NSAIDs in patients with SLE since 1966 was undertaken. We noted that, in this cohort of celecoxib-treated SLE patients from an office rheumatology practice, the majority demonstrated some improvement, and little toxicity was observed. SLE patients with self-reported sulfa allergies were not more likely to have adverse reactions to celecoxib than non-sulfa allergic patients. The literature review performed herein reveals that, although NSAID toxicity should be a continuing concern in an SLE population, structural dissimilarities between celecoxib and the sulfonamide antimicrobials may make true cross-allergenicity less likely to be a clinical problem. These results suggest that patients with SLE can be safely and effectively treated with celecoxib; however, further studies are needed to assess the effectiveness and safety of all NSAIDs in SLE.

Celecoxib-induced erythema multiforme with glyburide cross-reactivity

Erythema multiforme is an acute inflammatory skin reaction that often is caused by drugs, especially sulfonamides and their derivatives. Celecoxib, a cyclooxygenase-2 inhibitor, is a sulfonamide derivative commonly prescribed to treat arthritis in patients who cannot tolerate or who have a contraindication for taking traditional nonsteroidal antiinflammatory agents. A 57-year-old man with a previously undocumented sulfa allergy experienced an allergic skin reaction and had difficulty breathing secondary to throat swelling. His condition was believed to be erythema multiforme associated with the introduction of celecoxib into his drug regimen. His drug therapy was discontinued, but a subsequent reaction occurred when the sulfonamide derivative glyburide was reintroduced. It is important for clinicians to obtain a careful history and perform a thorough medical evaluation in all patients receiving sulfonamides and their derivatives, as a potentially life-threatening allergic reaction may be prevented.

Cox-2 inhibitors: today and tomorrow

The elucidation of inducible cyclooxygenase (Cox-2) dependent inflammatory pathways led to the development of specific Cox-2 inhibitors, the coxibs. These agents include the currently available celecoxib and rofecoxib and such second-generation agents as parecoxib, valdecoxib, and etoricoxib. The therapeutic advantage of coxibs is founded primarily in their lack of significant gastrointestinal (GI) side effects. Clinical trials have demonstrated the efficacy of coxibs to be completely comparable with traditional nonsteroidal anti-inflammatory drugs (NSAIDs), and pharmacoeconomics suggest favorable cost/benefit ratios with these agents compared with traditional NSAIDs, related to their reduced GI complication profiles and lower indirect costs associated with disability. Although several clinical questions remain (eg, use with low-dose aspirin, risk of thrombosis, myocardial infarction, edema, and hypertension), the emergence and clinical utility of coxibs is likely to continue on the basis of their efficacy and relative GI safety advantage. Although newer, more specific Cox-2 inhibitors may alter the choice, it is likely that this class of anti-inflammatories will become (if they have not already) the drugs of first choice in the treatment of acute pain, chronic pain, and most rheumatic conditions in the 21st century. In addition to the treatment of rheumatic conditions, it is possible that coxibs will also be of clinical utility in protection against malignant transformation and Alzheimer disease.

Allergic adverse reactions to sulfonamides

Antimicrobial sulfonamides were the first antimicrobial agents used effectively to treat infectious diseases. However, because they may cause severe adverse drug reactions (ADRs) and because more effective agents have since been developed, sulfonamides now are used for only a few indications in specific groups, such as AIDS patients. Skin reactions, from benign rash to potentially lethal toxidermias, are the most frequent ADRs to sulfonamides. Other major ADRs include acute liver injury, pulmonary reactions, and blood dyscrasias. Although the mechanisms involved have not been fully elucidated, reactive metabolites appear to play a pivotal role. The hydroxylamine and nitroso metabolites of sulfamethoxazole, the most frequently used sulfonamide today, can bind covalently to proteins because of their chemical reactivity, resulting in the induction of specific adverse immune responses. Therefore, changes in the activity of metabolic and detoxification pathways are associated with a greater risk for developing allergic reactions to sulfonamides. Allergies to sulfonamides, particularly sulfamethoxazole (often used in combination with trimethoprim as co-trimoxazole), are more frequent in AIDS patients, but the reason for this increased risk is not fully understood. No valid tools are available to predict which patients have a greater risk for developing allergies to sulfonamides. Diagnosis is essential to avoid a possible evolution toward severe reactions and readministration of the offending drug. In patients who absolutely require further treatment, successful desensitization may be achieved.

Should celecoxib be contraindicated in patients who are allergic to sulfonamides? Revisiting the meaning of 'sulfa' allergy

Celecoxib, a selective cyclo-oxygenase-2 inhibitor, is a diaryl-substituted pyrazole derivative containing a sulfonamide substituent. Because of this structural component, celecoxib is contraindicated for use in patients who have demonstrated allergic reactions to sulfonamides. However, there is a lack of data demonstrating cross-reactivity among sulfonamide medications. A sulfonamide is any compound with an SO2NH2 moiety. The major difference between sulfonamide antimicrobials and other sulfonamide-containing medications such as furosemide, thiazide diuretics and celecoxib, is that sulfonamide antimicrobials contain an aromatic amine group at the N4 position. This allows for division of the sulfonamides into 2 groups: aromatic amines (i.e., sulfonamide antimicrobials) and nonaromatic amines. In addition, sulfonamide antimicrobials contain a substituted ring at the N1-position; this group is not found with nonaromatic amine-containing sulfonamides. Adverse reactions to sulfonamide antimicrobials include type I, or immunoglobulin (Ig) E-mediated reactions, hypersensitivity syndrome reactions, and severe skin reactions such as toxic epidermal necrolysis. The aromatic amine portion of the sulfonamide antimicrobial is considered to be critical in the development of latter 2 reactions. In susceptible individuals, the hydroxylamine metabolite is unable to be detoxified leading to a cascade of cytotoxic and immunological events that eventually results in the adverse reaction. Since celecoxib does not contain the aromatic amine, adverse reactions such as hypersensitivity syndrome reactions and toxic epidermal necrolysis would not be expected to occur at the same frequency as they do with sulfonamide antimicrobials. Similarly, for IgE-mediated reactions, the N1-substituent and not the sulphonamide moiety is important in determining specificity to antibodies. Celecoxib and other nonaromatic amine-containing sulfonamide medications do not contain the N1-substituent. Cross-reactivity among the various sulfonamide-containing medications has also not been substantiated by published case reports. In fact, conflicting information exists in the literature. Reports showing lack of cross-reactivity balance the few case reports suggesting cross-reactivity. Cross-reactivity between sulfonamide medications should be based on scientific data, including chemistry, metabolism, immune responses and clinical data. Based on the current information, there is no documentation for cross-reactivity between sulfonamide antimicrobials and other sulfonamide medications, such as celecoxib.

Celecoxib and rofecoxib. The role of COX-2 inhibitors in dental practice

BACKGROUND

In recent years, dental practitioners have relied on ibuprofen and other nonsteroidal anti-inflammatory drugs, or NSAIDs--such as naproxen, diflunisal and ketoprofen--to manage acute and chronic orofacial pain. Two NSAIDs that recently came on the market, celecoxib and rofecoxib, have been developed to limit the adverse effects seen after chronic use of NSAIDs.

LITERATURE REVIEWED

The authors have summarized all available publications describing the human pharmacokinetics, clinical pharmacology and known adverse effects of these new specific cyclooxygenase-2, or COX-2, inhibitors.

CONCLUSIONS

Although peripherally acting analgesics are remarkably effective, chronic administration of nonselective COX inhibitors has been associated with gastrointestinal ulceration and prolonged bleeding. The authors present the distinctive mechanism of action for these new COX-2 inhibitors, compare their relative anti-inflammatory and analgesic properties and describe their safety profile. They also summarize indications, contraindications and dosing recommendations.

CLINICAL IMPLICATIONS

Celecoxib and rofecoxib are valuable dental therapeutic agents for the management of inflammatory joint disorders and associated chronic orofacial pain. Additionally, rofecoxib, with its more rapid onset, may be useful in treating selected cases of acute postsurgical pain.

COX-2 inhibitors in rheumatoid arthritis

The selective cyclooxygenase 2 (COX-2) inhibitors have emerged as an important option in the treatment of rheumatoid arthritis (RA). Rofecoxib and celecoxib, the selective COX-2 inhibitors currently available, have shown efficacy in reducing symptoms of RA comparable with that of traditional nonsteroidal antiinflammatory drugs (NSAIDs). The primary advantage of selective COX-2 inhibitors relates to reduced gastrointestinal (GI) toxicity. Gastroduodenal ulcers detected by endoscopy are markedly diminished in patients receiving selective COX-2 inhibitors versus those receiving NSAIDs. Moreover, unpublished data indicate that the risk of symptomatic and complicated ulcers is reduced by approximately half in patients prescribed rofecoxib or celecoxib. Despite these encouraging findings, selective COX-2 inhibitors have the potential for important adverse events such as impaired renal function, hypertension, and edema. Furthermore, clinicians must balance the competing demands of reducing GI risk while managing the increasing costs associated with selective COX-2 inhibitor use.

Identification of sulfonamide-like adverse drug reactions to celecoxib in the World Health Organization database

BACKGROUND

The selective COX-2 inhibitor celecoxib has a sulfonamide structure and is contraindicated for patients with known sulfa allergy. However, there is currently no standard available for the identification of sulfonamide-related adverse drug reactions (ADRs) and the occurrence of such ADRs with celecoxib has not been established. THE AIMS OF THIS STUDY WERE: (1) to identify the typical pattern of sulfonamide ADRs from literature and verify this pattern in the World Health Organization (WHO) ADR database; and (2) to examine whether these sulfonamide ADRs occur more frequently with celecoxib than with the non-sulfonamide, COX-2 inhibitor rofecoxib.

METHODS

A sulfonamide ADR pattern was derived from the most extensive textbook source of ADRs and applied to the WHO database for the three groups of sulfonamide drugs: short- and intermediate-acting sulfonamides, and sulfasalazine. ADRs reported three or more times for each of these groups were included in a 'sulfonamide template' comprising 19 ADRs relating to the skin, the blood, the liver, and anaphylaxis. This template was then applied to celecoxib and rofecoxib.

RESULTS

Overall, the relative reporting rate of a sulfonamide-type ADR with celecoxib was 80% higher than with rofecoxib, whether this was based on total number of reports (RR 1.8, 95% Cl 1.6-1.9) or restricted to reports that listed coxibs as the sole suspected drugs (RR 1.8, 95% Cl 1.6-1.9). There were numerically more ADRs for celecoxib than for rofecoxib in 15 of the 19 terms. Within the ADRs in the sulfonamide template, relative reporting rate of fatal reactions was 80% higher with celecoxib (RR 1.8, 95% Cl 0.9-4.0). Even though serious sulfonamide reactions are rare, their clinical impact on patient safety warrants close monitoring as more data becomes available. Physicians should be aware of possible sulfonamide allergy when prescribing celecoxib.

Celecoxib: a new option in the treatment of arthropathies and familial adenomatous polyposis

The discovery of the two isoenzymes of cyclooxygenase (COX) has recently lead to the development and clinical introduction of specific inhibitors of cyclooxygenase-2 (COX-2), such as celecoxib, onto the market. Celecoxib is an effective anti-inflammatory, analgesic and antipyretic agent therapeutically utilised in the management of osteoarthritis and rheumatoid arthritis. In addition, celecoxib has some novel therapeutic and pharmacological activities. Celecoxib inhibits anti-apoptotic kinase activation and is the first specific COX-2 inhibitor to be marketed for familial adenomatous polyposis, an inheritable predisposition for colorectal cancer. Celecoxib is not without gastrointestinal (GI) side effects but demonstrates markedly reduced GI ulceration in clinical trials when compared to traditional non-specific non-steroidal anti-inflammatory drugs (NSAIDs). The specific COX-2 inhibitors each have distinctive pharmacokinetic properties. Celecoxib can be given either once or twice daily. Racial differences in drug disposition, and pharmacokinetic changes in elderly patients, patients with chronic renal insufficiency and patients with mild to moderate hepatic impairment, are evident with celecoxib. Despite the specific action of these drugs, there remains the potential for significant drug interactions. Celecoxib has demonstrated interactions with fluconazole, lithium and warfarin. Increased clinical vigilance should be maintained when co-prescribing medications with celecoxib until further clinical experience is gained. Celecoxib represents a major therapeutic advance in terms of GI safety. However, long-term safety in other organ systems, safety with concomitant drug administration, and pharmacoeconomic benefits still remain to be proven.

Celecoxib: a review of its use in osteoarthritis, rheumatoid arthritis and acute pain

Celecoxib is a cyclo-oxygenase (COX) inhibitor that exhibits relative in vitro and ex vivo selectivity for COX-2 over COX-1. Results of randomised double-blind multicentre studies indicate that celecoxib is superior to placebo and has similar efficacy as conventional nonsteroidal anti-inflammatory drugs (NSAIDs) in improving the signs and symptoms of osteoarthritis and rheumatoid arthritis. Analgesic efficacy and improvements in functional status are apparent within 2 weeks of starting therapy and are maintained throughout treatment. Available data suggest that celecoxib has analgesic efficacy in patients with postsurgical dental pain, although this is yet to be confirmed. In patients with osteoarthritis of the knee, celecoxib 100 and 200 mg and naproxen 500 mg twice daily were similarly efficacious and superior to placebo. Once and twice daily celecoxib dosage regimens provided comparable efficacy. Improvements in physical function paralleled those in pain relief. Celecoxib also has efficacy in treating the signs and symptoms of osteoarthritis of the hip. The effects of celecoxib were not diminished in elderly patients with osteoarthritis of the hip or knee. All dosages of celecoxib (100 to 400 mg twice daily) and naproxen 500 mg twice daily produced significant anti-inflammatory and analgesic effects in patients with active rheumatoid arthritis. In patients with stable rheumatoid arthritis, celecoxib 200 mg twice daily showed sustained symptomatic improvements similar to those of twice daily slow-release diclofenac 75 mg over a 24-week period. Celecoxib was well tolerated in clinical trials. Upper gastrointestinal complications occurred in significantly fewer patients treated with twice daily celecoxib 25 to 400 mg than in those receiving comparator NSAIDs. There was no evidence of a dose relationship in endoscopic ulcer development and incidences in celecoxib and placebo recipients were lower than in those receiving twice daily naproxen 500 mg or ibuprofen 800 mg 3 times daily.

CONCLUSIONS

Celecoxib is the first COX-2 specific inhibitor approved for use in osteoarthritis and rheumatoid arthritis. Celecoxib produces significant improvements in pain and inflammation and these effects are maintained during treatment for up 24 weeks in clinical trials. Studies indicate that celecoxib has similar efficacy to conventional NSAIDs in relieving pain and improving functional status, but is associated with a lower incidence of upper gastrointestinal ulceration and complications. This promising gastrointestinal safety profile, together with sustained symptomatic relief, places celecoxib as a useful alternative for the treatment of osteoarthritis and rheumatoid arthritis, particularly in patients at high risk of developing gastrointestinal events. Although data are encouraging, its place in acute pain states remains to be established.

Clinical pharmacokinetics and pharmacodynamics of celecoxib: a selective cyclo-oxygenase-2 inhibitor

Celecoxib, a nonsteroidal anti-inflammatory drug (NSAID), is the first specific inhibitor of cyclo-oxygenase-2 (COX-2) approved to treat patients with rheumatism and osteoarthritis. Preliminary data suggest that celecoxib also has analgesic and anticancer properties. The selective inhibition of COX-2 is thought to lead to a reduction in the unwanted effects of NSAIDs. Upper gastrointestinal complication rates in clinical trials are significantly lower for celecoxib than for traditional nonselective NSAIDs (e.g. naproxen, ibuprofen and diclofenac). The rate of absorption of celexocib is moderate when given orally (peak plasma drug concentration occurs after 2 to 4 hours), although the extent of absorption is not known. Celexocib is extensively protein bound, primarily to plasma albumin, and has an apparent volume of distribution of 455+/-166L in humans. The area under the plasma concentration-time curve (AUC) of celecoxib increases in proportion to increasing oral doses between 100 and 800mg. Celecoxib is eliminated following biotransformation to carboxylic acid and glucuronide metabolites that are excreted in urine and faeces, with little drug (2%) being eliminated unchanged in the urine. Celecoxib is metabolised primarily by the cytochrome P450 (CYP) 2C9 isoenzyme and has an elimination half-life of about 11 hours in healthy individuals. Racial differences in drug disposition and pharmacokinetic changes in the elderly have been reported for celecoxib. Plasma concentrations (AUC) of celecoxib appear to be 43% lower in patients with chronic renal insufficiency [glomerular filtration rate 2.1 to 3.6 L/h (35 to 60 ml/min)] compared with individuals with healthy renal function, with a 47% increase in apparent clearance. Compared with healthy controls, it has been reported that the steady-state AUC is increased by approximately 40% and 180% in patients with mild and moderate hepatic impairment, respectively. Celecoxib does not appear to interact with warfarin, ketoconazole or methotrexate; however, clinically significant drug interactions with fluconazole and lithium have been documented. As celecoxib is metabolised by CYP2C9, increased clinical vigilance is required during the coadministration of other substrates or inhibitors of this enzyme.