Erythema multiforme secondary to dimenhydrinate in a patient with previous similar reactions to pamabrom.

OBJECTIVE: To report a case of erythema multiforme secondary to dimenhydrinate and pamabrom cross-sensitivity. CASE SUMMARY: A 22-year-old Chinese female presented with a complaint of lip mucosal ulceration with necrosis and stomatitis, worsening over the past 24 hours and associated with reduced oral intake and incomplete opening of the mouth. Presentation was accompanied by a generalized rash and genital mucosal involvement. The only new systemically ingested agent was dimenhydrinate approximately 4 days prior to admission. She had no significant medical history, but was labeled to be allergic to acetaminophen. She had a positive history of 2 similar presentations secondary to Panadol Menstrual (acetaminophen and pamabrom), once 3 years ago and again 5 months prior to the current admission. An objective causality assessment revealed that the adverse drug event was "probable" to dimenhydrinate. A detailed history revealed a negative drug challenge to acetaminophen. She had previously taken plain acetaminophen and Beserol (acetaminophen and chlormezanone) with no reaction. DISCUSSION: A comprehensive history taking facilitated the diagnosis of erythema multiforme secondary to dimenhydrinate without the need to perform invasive testing, and the removal of erroneous allergy labeling to acetaminophen. Dimenhydrinate and pamabron both contain theophylline-related structures in their chemical composition. Similar reactions to pamabrom strongly suggested cross-sensitivity to theophylline-related structures. CONCLUSIONS: To our knowledge, this is the first report of erythema multiforme due to dimenhydrinate with pamabron cross-sensitivity. We recommend that comprehensive medication-history taking be carried out for all drug-allergy patients to ensure greater informed decision making when choosing medications to use for that patient in the future.

Development and validation of the INappropriate solid oral dosaGE form modification aSsessmenT (INGEST) Algorithm using data of patients with medication dysphagia from a neurology ward and nursing home in Singapore.

OBJECTIVES: This study aims to develop and validate a novel implicit tool to assist clinicians in resource-limited settings to promptly assess suitability for modification of solid oral dosage forms (SODFs) during medication prescribing, review and/or administration for patients with dysphagia. DESIGN: Literature review and a group discussion were conducted to elicit items for the construction of the INappropriate solid oral dosaGE form modification aSsessmenT (INGEST) algorithm. For its validation, inter-rater reliability among three independent users was evaluated. Accuracy of users' ratings was also evaluated against the screening results using the Don't Rush to Crush handbook. SETTING AND PARTICIPANTS: Three pharmacists were involved in the development and another three were involved in the validation of the INGEST algorithm using anonymised medication records of 50 patients in a nursing home and a hospital ward; only SODFs that were modified prior to administration were evaluated. RESULTS: Following literature review, considerations included by consensus in the INGEST algorithm were the presence of special coating or modified release characteristics of the SODF medications, hazardous nature and taste of the active ingredients, manufacturer's advice and use of tube feeding. Of the 381 SODF medications evaluated, 26 (6.8%) were identified by at least one pharmacist to be inappropriate for modification. Gwet's AC among the three pharmacists in identifying SODF medications inappropriate for modification was 0.75 (p<0.001, 95% CI 0.63 to 0.87), and 0.80 (p<0.001, 95% CI 0.71 to 0.89) in identifying SODF medications appropriate for modification, suggesting substantial inter-rater agreement. Overall accuracy of each pharmacist's ratings was high, ranging from 93.7% to 95.6%. CONCLUSIONS: The implicit INGEST algorithm has potential for use by clinicians in nursing home and hospital settings for determining suitability of SODF medications for modification. Further studies should be conducted to assess its external validity and utilisation in daily practice for improving clinical outcomes for patients with SODF dysphagia.

A cost analysis of Outpatient Parenteral Antibiotic Therapy (OPAT): an Asian perspective.

The concept of Outpatient Parenteral Antibiotic Therapy (OPAT) is relatively new in Asia. This study compared the actual costs and outcomes of care involving OPAT with conventional inpatient-only care at a university hospital in Singapore. Actual costs were obtained for selected patients enrolled in OPAT after 1 January 2005 and these costs were directly compared with those of age-, gender- and diagnosis-matched patients managed as inpatients only prior to the availability of OPAT in the preceding 12 months. Outcomes of patients were also considered. The OPAT and inpatient-only groups comprised 72 and 93 enrollments, respectively. Mean treatment duration for OPAT patients was 42.5 days versus 19 days for those receiving inpatient-only care (P < 0.001). The mean total treatment cost for OPAT and inpatient-only care was US$12 736 and $12 403, respectively (P = 0.706). Mean cost per day for care including an OPAT episode was US$278 versus $457 per day for inpatient-only care (P < 0.001). There was no difference in outcomes between the two groups. OPAT is a viable alternative to inpatient care as it is safe, effective and results in lower daily costs. The trend to longer treatment courses is worthy of further review.

Identification and evaluation of pharmacists' commonly used drug information sources.

BACKGROUND: Given the rate at which new medications are introduced to the market, as well as the diversity of existing drugs, pharmacists frequently need to consult drug information (DI) sources. Currently, there is a lack of information about pharmacists' needs for and sources of DI in Singapore. OBJECTIVE: To examine where practicing pharmacists in Singapore usually obtain DI and how useful and satisfactory the source is to pharmacists and to determine the kind of drug-related questions pharmacists usually receive. METHODS: An online survey was sent to registered hospital and community pharmacists who were members of the Pharmaceutical Society of Singapore. The survey consisted of questions about the pharmacists' demographics, what DI source they used most often, their satisfaction with that DI source, and how frequently they received various DI questions. RESULTS: A total of 156 pharmacists responded to the survey, for a response rate of 27.4%. The majority (82.7%) of the respondents chose reference texts as their most commonly used DI source; of these, 38.0% used the Drug Information Handbook. Reference texts were mostly rated very comprehensive (34.1%) or somewhat comprehensive (54.3%), whereas Web sites or search engines were mostly rated somewhat comprehensive (69.6%) or brief (21.7%). Most pharmacists believed that the information from reference texts could usually (51.2%) or always (48.8%) be trusted. Community pharmacists received questions on over-the-counter drugs and comparisons of drug efficacy more frequently than did hospital pharmacists (p < 0.001 and p = 0.001, respectively), whereas hospital pharmacists more frequently received questions on pharmacokinetics (p = 0.001). CONCLUSIONS: Most pharmacists in Singapore use reference texts when searching for general DI, and they find these texts more comprehensive and trustworthy than other available sources. The results also show that pharmacists in different settings receive different types of DI questions and have adequate resources to answer general DI questions.

Characterisation and outcomes of adult patients with paracetamol overdose presenting to a tertiary hospital in Singapore.

INTRODUCTION: Paracetamol is the most common pharmaceutical agent implicated in toxic exposure in Singapore. This study aimed to describe the characteristics of paracetamol overdose in the adult population managed at a tertiary healthcare facility in Singapore. METHODS: Medical records of adult patients hospitalised with a diagnosis of paracetamol overdose at National University Hospital, Singapore, over a three-year period from January 2011 to December 2013 were retrospectively reviewed. RESULTS: A total of 177 patients had paracetamol overdose. The median age was 25 years, with a significant female predominance (71.2%). Intentional ingestion accounted for the majority (76.8%) of cases. The median dose of paracetamol ingested was 10 (interquartile range 8-15) g. Among patients who reported ingesting more than 10 g, 46.5% perceived the overdose as non-lethal. N-acetylcysteine was administered in 76.3% of patients, among whom 24.4% experienced an anaphylactoid reaction. Of the 10 (5.6%) patients who had severe hepatotoxicity, 2 (1.1%) developed acute liver failure. Most patients had resolving transaminases at discharge and none required liver transplantation. The median length of hospitalisation was three days. There were no fatalities. CONCLUSION: Paracetamol overdose occurred predominantly in young adults with intentional ingestion, suggesting that preventive measures targeted at promoting public awareness may not suffice. However, the perceived lack of lethality by many patients who ingested potentially toxic amounts of paracetamol reflects a certain knowledge gap. Healthcare providers should proactively educate consumers on the proper use of paracetamol and the consequences of its overdose.

Pentoxifylline-Induced Thrombocytopenia: A Case Report.

Pentoxifylline-induced thrombocytopenia is rare, and information is lacking about its presentation. We describe a 72-year-old Chinese male who developed thrombocytopenia after initiation of pentoxifylline for the treatment of chronic lower limb ischemia due to peripheral artery disease. Venous thromboembolism had been ruled out with an ultrasound. Vascular surgeons had also determined there was no indication for surgical intervention. Four days after initiation of pentoxifylline, he developed thrombocytopenia, and his platelets were 68 × 10(3)/µL. He was not in overt disseminated intravascular coagulation (DIC), based on his International Society for Thrombosis and Hemostasis (ISTH) DIC score of 4. Dengue fever, which is endemic in Singapore, was ruled out. Pseudothrombocytopenia was also excluded with a peripheral blood film. When his platelets continued to fall, pentoxifylline was discontinued on the fifth day of treatment, and platelets normalized 48 hours after discontinuation. Pentoxifylline was a probable cause of thrombocytopenia using the Naranjo Adverse Drug Reaction Probability Scale (score = 7). The patient did not receive further doses of pentoxifylline. Prescribers should be aware of the risk of thrombocytopenia with pentoxifylline therapy and discontinue its use promptly if it is suspected.

Hemolysis as a potential complication of acetaminophen overdose in a patient with glucose-6-phosphate dehydrogenase deficiency.

A 21-year-old Chinese man who took an overdose of acetaminophen was hospitalized. His medical history was significant for glucose-6-phosphate dehydrogenase (G6PD) deficiency. On admission, physical examination was unremarkable and laboratory results were within normal limits. During his hospitalization, the patient experienced a decrease in hemoglobin concentration of almost 4 g/dl and an increase in unconjugated bilirubin consistent with the development of hemolysis. Acetaminophen was the most likely cause of the hemolysis. Clinicians must be aware of this potential complication after acetaminophen overdose in G6PD-deficient patients.

Acetylcysteine treatment for non-acetaminophen-induced acute liver failure.

OBJECTIVE: To evaluate the effectiveness of intravenous acetylcysteine in the treatment of non-acetaminophen-induced acute liver failure (ALF). DATA SOURCES: A search of MEDLINE (1966-March 2003), International Pharmaceutical Abstracts (1970-2003), and Cochrane Library (2003, issue 3) databases was conducted, using the search terms acetylcysteine, non-acetaminophen-induced hepatic failure, liver failure, intravenous, and treatment. DATA SYNTHESIS: All of the studies found were small and do not provide conclusive evidence that acetylcysteine benefits this subgroup of patients. Microvascular regional benefits were seen, but clinical outcomes have not been studied. CONCLUSIONS: Intravenous acetylcysteine should not be used routinely for treatment of non-acetaminophen-induced ALF. Further large-scale studies are needed to evaluate clinical outcomes.