Rapid oral desensitization to trimethoprim-sulfamethoxazole in infants and children

Sulfadiazine Hypersensitivity and Desensitization in Children With Congenital Toxoplasmosis: A Report on Two Cases

Combination therapy for toxoplasmosis consists of sulfadiazine, pyrimethamine and leucovorin. Although sulfadiazine can cause hypersensitivity reactions, such as fever, rash and liver dysfunction, there is no consensus on an effective therapy for congenital toxoplasmosis (CTox) without sulfadiazine. We attempted desensitization to sulfadiazine in 2 patients with CTox and sulfadiazine hypersensitivity. Desensitization was achieved for 1 patient.

Clinical applications of drug desensitization in the Asia-Pacific region

Drug desensitization is the induction, within hours to days, of a temporary state of tolerance to a drug which the patient has developed a hypersensitivity reaction to. It may be used for IgE and non-IgE mediated allergic reactions, and certain non-allergic reactions. The indication for desensitization is where no alternative medications are available for the treatment of that condition, and where the benefits of desensitization outweigh the risks. Desensitization is a therapeutic modality for drug allergy (similar to allergen specific immunotherapy for allergic rhinitis and insect venom anaphylaxis). In contrast, the drug provocation test is a diagnostic modality used to confirm or refute the diagnosis of drug allergy. This review discusses the clinical applications of desensitization for the treatment of common infectious, metabolic and cardiovascular diseases, and oncological conditions in the Asia-Pacific region.

General considerations on rapid desensitization for drug hypersensitivity - a consensus statement

Drug hypersensitivity reactions can occur with most drugs, are unpredictable, may affect any organ or system, and range widely in clinical severity from mild pruritus to anaphylaxis. In most cases, the suspected drug is avoided in the future. However, for certain patients, the particular drug may be essential for optimal therapy. Under these circumstances, desensitization may be performed. Drug desensitization is defined as the induction of a temporary state of tolerance of a compound responsible for a hypersensitivity reaction. It is performed by administering increasing doses of the medication concerned over a short period of time (from several hours to a few days) until the total cumulative therapeutic dose is achieved and tolerated. It is a high-risk procedure used only in patients in whom alternatives are less effective or not available after a positive risk/benefit analysis. Desensitization protocols have been developed and are used in patients with allergic reactions to antibiotics (mainly penicillin), insulins, sulfonamides, chemotherapeutic and biologic agents, and many other drugs. Desensitization is mainly performed in IgE-mediated reactions, but also in reactions where drug-specific IgE have not been demonstrated. Desensitization induces a temporary tolerant state, which can only be maintained by continuous administration of the medication. Thus, for treatments like chemotherapy, which have an average interval of 4 weeks between cycles, the procedure must be repeated for every new course. In this paper, some background information on rapid desensitization procedures is provided. We define the drugs and drug reactions indicated for such procedures, describe the possible mechanism of action, and discuss the indications and contraindications. The data should serve as background information for a database (accessible via the EAACI-homepage) with standardized protocols for rapid desensitization for antibiotics, chemotherapeutic agents, monoclonal antibodies/fusion proteins, and other drugs.

10. Drug allergy

Adverse drug reactions are common, but only 6% to 10% are immunologically mediated. Unlike most adverse drug reactions, allergic drug reactions are unpredictable. Whereas some drug-induced allergic reactions may be easily classified into one of the four Gell and Coombs hypersensitivity categories, many others that appear to have an immunologic component cannot be classified because of our lack of mechanistic information. Theoretically, any drug can induce an immune response. However, some drugs are more likely to elicit clinically relevant immune responses than are others. Drugs in this category include antimicrobial drugs, anticonvulsants, chemotherapeutic agents, heparin, insulin, protamine, and biologic response modifiers. After a drug-disease connection is established, it must be determined whether the reaction was immunologically mediated. Subsequently, confirmatory tests, if available, should be used to determine the allergic status of the patient. If these tests are not available, a graded challenge or desensitization may be considered, depending on the type of clinical reaction previously demonstrated and the need for drug readministration. Education of the patient and primary care physician is an important component of patient management.

Successful resumption of trimethoprim-sulfamethoxazole after oral desensitisation in patients with chronic granulomatous disease

Two patients with chronic granulomatous disease who had previously been intolerant to trimethoprim-sulfamethoxazole because of various adverse reactions completed a desensitisation protocol with a favourable clinical outcome.

Trimethoprim-sulfamethoxazole

After 25 years of use in the United States, trimethoprim-sulfamethoxazole (TMP-SMX) is widely prescribed for various indications. By virtue of sequential blockade of microbial folic acid synthesis, the antimicrobial combination has excellent in vitro inhibitory activity against many common respiratory and urinary tract pathogens, as well as many nosocomial infecting strains. In patients infected with the human immunodeficiency virus, TMP-SMX provides prophylactic and therapeutic potency against Pneumocystis carinii but at the risk of frequent side effects. TMP-SMX is also used for treatment of pulmonary and disseminated nocardiosis and some forms of Wegener's granulomatosis, as well as for prophylaxis of spontaneous bacterial peritonitis. Increasing bacterial resistance and concern about occasional severe adverse effects suggest that the usefulness of TMP-SMX may diminish in the future.

Managing drug reactions to sulfonamides and other drugs in HIV infection: desensitization rather than rechallenge?

Drug reactions in patients with HIV infection, e.g. fever or rash, are a frequently occurring clinical problem. These side effects particularly are observed with sulfonamides; however, many other drugs have also shown to induce allergic reactions when given to patients with HIV infection. The production of hydroxylamines has been put forward as one of the explanations for these high incidence of reactions on drugs. Since sulfonamides are the first choice of therapy for the treatment and prophylaxis of Pneumocystis carinii pneumonia, several strategies have been developed to circumvent drug reactions. In general rechallenge or desensitization are recommended in literature. This article discusses the results and risks of rechallenge and desensitization with sulfonamides or other drugs, as mentioned in the literature. Furthermore preliminary results of rechallenge with a sulfonamide, which is not metabolized into hydroxylamines, are presented. From the data in the literature it is concluded that desensitization should be preferred to rechallenge.

Efficacy of MK-991 (L-743,872), a semisynthetic pneumocandin, in murine models of Pneumocystis carinii

In addition to its potent efficacy in animal models against Candida sp., Aspergillus fumigatus, and Histoplasma capsulatum, the clinical candidate pneumocandin MK-991 (formerly L-743,872) was also extremely potent against Pneumocystis carinii in models of immune-compromised animals. MK-991 was approximately 14 times more potent than the original natural product lead, pneumocandin B0. The 90% effective dose (ED90) of MK-991 for cyst clearance in the rat model for pneumocystis was 0.011 mg/kg of body weight when delivered parenterally for 4 days twice a day (b.i.d.). In a mouse model, under the same experimental parameters, the ED90 was 0.02 mg/kg. MK-991 was also effective orally, with an ED90 for cyst clearance of 2.2 mg/kg against acute infection in rats (b.i.d. for 4 days). Complete prevention of P. carinii development was achieved in immunocompromised mice at a daily oral dose of 2.25 mg/kg. As reported previously for other pneumocandins and echinocandins, MK-991 selectively prevented the development of P. carinii cysts. When used as a prophylactic agent, neither stage of the organism appeared in the lungs of animals. In response to an acute infection, cysts were eliminated rapidly, while trophozoite forms persisted. Despite good efficacy as an oral agent in murine models, the low oral absorption of this class may limit the use of MK-991 to parenteral therapy.

Adverse reactions to trimethoprim-sulfamethoxazole among children with human immunodeficiency virus infection

BACKGROUND

The clinical course of HIV infection is frequently different among infants and children from that in adults. In adults among the most common sources of morbidity related to therapy are adverse drug reactions, notably to trimethoprim-sulfamethoxazole. Although there are case reports of serious adverse reactions to trimethoprim-sulfamethoxazole among infants and children with HIV infection, the precise rate and clinical characteristics of these adverse reactions among HIV-infected children are unknown.

METHODS

We reviewed the clinical records of all children referred to a regional HIV clinic in a 6-year period. Therapy and suspected adverse drug reactions to therapy were reviewed by one of the investigators not involved in patient care. Adverse drug reactions were identified and characterized according to previously established criteria.

RESULTS

During this time 78 children were referred for assessment of possible HIV infection, 45 of whom were ultimately determined to have the infection. Twenty-five were treated with trimethoprim-sulfamethoxazole, 15 (60%) of whom tolerated therapy and 10 (40%) of whom had adverse reactions. The most common type of adverse reaction was erythema multiforme (70%), followed by neutropenia (20%) and Stevens-Johnson syndrome (10%). In two patients a serious adverse reaction to trimethoprim-sulfamethoxazole led to the diagnosis of HIV infection.

CONCLUSIONS

The overall incidence and type of serious adverse reactions to trimethoprim-sulfamethoxazole among infants and children with HIV infection appear to be similar to those among adults.