Hematologic effects of antipyretic analgesics. Drug-induced agranulocytosis

Pharmacological Management of Acute Endodontic Pain

Pain associated with infections of the tooth pulp and periapical tissues is intense and often the most common reason for patients seeking emergency dental care. Effective management of acute dental pain requires a deep understanding of pain mechanisms, which enables accurate diagnosis and definitive treatment. While drugs are only used as an adjunct to definitive dental treatment, a thorough understanding of their mechanism of action and effectiveness enables clinicians to effectively control intra-operative and post-operative pain and prevent persistent pain. This review describes how pain is detected, processed, and perceived. It also provides information on evidence-based strategies on the use of different classes of drugs to effectively manage endodontic pain.

Real-world prevalence and consequences of potential drug-drug interactions in the first-wave COVID-19 treatments

WHAT IS KNOWN AND OBJECTIVE

Initial treatment recommendations of COVID-19 were based on the use of antimicrobial drugs and immunomodulators. Although information on drug interactions was available for other pathologies, there was little evidence in the treatment of COVID-19. The objective of this study was to analyse the potential drug-drug interactions (pDDIs) derived from the medication used in COVID-19 patients in the first pandemic wave and to evaluate the real consequences of such interactions in clinical practice.

METHODS

Cohort, retrospective and single-centre study carried out in a third-level hospital. Adult patients, admitted with suspected COVID-19, that received at least one dose of hydroxychloroquine, lopinavir/ritonavir, interferon beta 1-b or tocilizumab and with any pDDIs according to "Liverpool Drug Interaction Group" between March and May 2020 were included. The possible consequences of pDDIs at the QTc interval level or any other adverse event according to the patient's medical record were analysed. A descriptive analysis was carried out to assess possible factors that may affect the QTc interval prolongation.

RESULTS AND DISCUSSION

Two hundred and eighteen (62.3%) patients of a total of 350 patients admitted with COVID-19 had at least one pDDI. There were 598 pDDIs. Thirty-eight pDDIs (6.3%) were categorized as not recommended or contraindicated. The mean value difference between baseline and pDDI posterior ECG was 412.3 ms ± 25.8 ms vs. 426.3 ms ± 26.7 ms; p < 0.001. Seven patients (5.7%) had a clinically significant alteration of QTc. A total of 44 non-cardiological events (7.3%) with a possible connection to a pDDI were detected.

WHAT IS NEW AND CONCLUSION

The number of pDDIs in patients admitted for COVID-19 in the first pandemic wave was remarkably high. However, clinical consequences occurred in a low percentage of patients. Interactions involving medications that would be contraindicated for concomitant administration are rare. Knowledge of these pDDIs and their consequences could help to establish appropriate therapeutic strategies in patients with COVID-19 or other diseases with these treatments.

Adjunct dipyrone in association with oral morphine for cancer-related pain: the sooner the better

INTRODUCTION

Adjunct nonopioid analgesics may improve pain control in patients with cancer needing morphine or its derivates. Dipyrone is a cheap nonopioid analgesic widely used in many countries.

OBJECTIVE

The objective of the study was to evaluate, whenever morphine was started, if associating dipyrone with it would improve pain control and if this effect was time dependent.

MATERIALS AND METHODS

This is a double-blind placebo-controlled randomized crossover study. Thirty-four ambulatory cancer patients experiencing cancer-related pain for which oral morphine was to be started at the dose of 10 mg orally (PO) every 4 h were randomized to take either dipyrone 500 mg PO every 6 h or placebo. After 48 h, patients would be switched from dipyrone to placebo and vice versa. Pain was the primary outcome and was measured using a visual analogue scale before starting medications, at 48 and 96 h.

RESULTS

We randomized 16 patients to start with placebo (group 1) and 18 with dipyrone (group 2). Pain scores for groups 1 and 2 were at baseline: 7.31 +/- 0.29 vs 6.88 +/- 0.28 (p = 0.3), at 48 h: 7.06 +/- 0.32 vs 5.5 +/- 0.31 (p = 0.001), and at 96 h: 3.18 +/- 0.39 vs 1.94 +/- 0.37 (p = 0.03). Both groups had significant improvements in pain scores after introducing dipyrone (p < 0.001, for both). Main toxicities were nausea, vomiting, epigastric pain, and myalgias. Twenty-eight patients chose dipyrone, four placebo, and two were indifferent.

CONCLUSIONS

We conclude that dipyrone adds significantly to the analgesic effect of morphine and, when given at the time of starting morphine, results in better pain scores even after dipyrone is discontinued.

Metamizole use among Hispanics in Miami: report of a survey conducted in a primary care setting

BACKGROUND

Metamizole (dipyrone) is a myelotoxic, nonsteroidal anti-inflammatory agent that has been banned from the US market since 1979. However, dipyrone may be purchased in some areas of the US. We conducted a survey in a primary care setting in Miami, Florida to determine the prevalence of metamizole possession and use among Hispanics living in this area.

METHODS

Participants consisted of 137 Hispanic outpatients interviewed consecutively during a primary care visit in the month of February 2005.

RESULTS

Metamizole was possessed by 28% of the surveyed population. The most common reasons for using dipyrone were pain (72%) and fever (24%). The vast majority of patients had purchased the medication in Latin America (95%), in most instances without a prescription (95%). Nineteen patients (13%) had used the medication during the previous year.

CONCLUSIONS

Metamizole is available to Latino immigrants who reside in the US, despite the FDA ban imposed in 1977.

Dipyrone-induced granulocytopenia: a case for awareness

Dipyrone, also known as metamizole, is an analgesic and antipyretic drug that was banned by the United States Food and Drug Administration because of its association with agranulocytosis. However, it is still produced and marketed in several countries in Central and South America as well as in Europe, Asia, and Africa. It can also be found in the United States, where illegal sales have been reported in California gift shops, markets, bakeries, and other retail establishments. Dipyrone is commonly found in the homes of families who are originally from areas where it is still lawfully marketed. We describe a patient who developed granulocytopenia and fever after taking dipyrone and discuss the available literature. Our aim is to raise awareness of this drug, which is commonly used outside the United States, and to call attention to its well-known and potentially lethal side effect.

Metamizole use by Latino immigrants: a common and potentially harmful home remedy

A 4-year-old boy presented with fever, septic arthritis, and persistent neutropenia. Bone marrow biopsy revealed no evidence of neoplasia. Additional history disclosed that the patient had been given metamizole for pain before onset of his illness. Metamizole, a nonsteroidal antiinflammatory agent, is prohibited in the United States because of the risk of agranulocytosis but is widely used in Mexico and other countries. The increasing number of Latinos in the United States and the extensive cross-border transfer of medicines raise concerns that metamizole use and associated complications may become more frequent. After identification of the index patient, additional inquiry revealed that the patient's mother was hospitalized previously for overwhelming sepsis associated with metamizole use. These cases prompted an investigation of metamizole use in an urban pediatric clinic, which revealed that 35% of Spanish-speaking Latino families had used metamizole; 25% of these families had purchased the medication in the United States. We conclude that metamizole use is common and may be underrecognized in immigrant Latino patients. Physicians in the United States, especially those who practice primary care, hematology/oncology, and infectious diseases, must be aware of the availability and use of metamizole in specific patient populations and its potential for harmful side effects.

Use of Neo-melubrina, a banned antipyretic drug, in San Diego, California: a survey of patients and providers

BACKGROUND

Dipyrone is an antipyretic drug that has been associated with agranulocytosis. It is banned in the United States but is available in Mexico under the name Neo-melubrina.

OBJECTIVES

To define the use of Neo-melubrina in the Hispanic population of 2 San Diego, California, community clinics and to determine local physicians' and nurse practitioners' awareness of the drug and its risks.

DESIGN

Patient survey and provider survey.

PARTICIPANTS

PATIENTS

200 parents of Hispanic pediatric patients. Providers: members of San Diego chapters of the American Academy of Pediatrics, the American Academy of Family Physicians, and the California Coalition of Nurse Practitioners.

MAIN OUTCOME MEASURES

Self-reported use of Neo-melubrina by patients, and provider awareness of Neo-melubrina and its most significant side effects.

RESULTS

Of the 200 patients, 76 (38.0%) reported a lifetime use of Neo-melubrina. Most (56%) used it for both pain and fever. Most providers were unable to correctly identify why Neo-melubrina might be used or its adverse effects. Physicians answered correctly more often than nurse practitioners and pediatric providers more often than family medicine providers. Providers who trained within 75 miles of the US-Mexico border, who reported a patient population of more than 50% Hispanic, and who were resident physicians at the time of the survey were most likely to answer correctly.

CONCLUSIONS

Neo-melubrina has been used by a substantial percentage of Hispanic patients in the community clinics surveyed. Many San Diego health care providers are unaware of this medication and may, therefore, miss opportunities to educate patients about safer alternatives.

Scientific standards and the design of case-control research

A new controversy has emerged over the results of a case-control study alleging a causal relationship between certain non-steroidal anti-inflammatory agents (NSAIAs) and the risks of agranulocytosis and aplastic anemia. After describing the methods and results of the International Agranulocytosis and Aplastic Anemia (IAAA) study, we review the distinctive methodologic challenges of this study and the requirements for avoiding bias, and then reconcile the study results with the principles of case-control design. As a result of our analysis, we believe that the IAAA study's most important and reliable finding is its documentation of the infrequent occurrences of aplastic anemia and agranulocytosis with analgesic use. In contrast, a causal association between NSAIAs and blood dyscrasias has not been suitably established, and may well have resulted from several distinctive sources of bias. These include the effects of diagnostic-suspicion bias in case determination, of exclusion bias in choosing controls, of recall bias in determining exposure, and of publicity bias in both case selection and ascertainment of exposure. These problems could have been avoided and a more valid result obtained with closer attention to the experimental paradigm for case-control research.

Benefit-risk assessment of investigational drugs: current methodology, limitations, and alternative approaches

Development of investigational drugs is a process integrated traditionally into four overlapping phases. The goal is to introduce new therapies to clinical medicine by assessing benefits and risks associated with administering the new drug. Benefit assessment is performed with respect to the disease for which the drug may comprise an effective treatment. In contrast, safety assessment is relatively standardized across many pharmacologic classes of agents. For purposes of benefit-risk assessment, investigational drugs are developed to provide benefit in three major disease categories: acute, episodic, and chronic. Benefit assessment is the major focus of conventional methodologies. Inherent limitations of risk assessment produced by conventional approaches are illustrated by the historical inability to detect toxicities of various drugs until large patient populations have been treated, typically after the drug is marketed. Alternative approaches to overcome these limitations include assessment of safety in studies specifically designed to optimize such evaluation and more extensive safety testing of investigational drugs in patient subgroups at higher risk. Such approaches serve the interest of patients, physicians, and developers by facilitating the development of new therapies by providing a more complete benefit-risk assessment prior to initial marketing of the drug.