Polypharmacy and Drug Interactions in the COVID-19 Pandemic.

The COVID-19 pandemic generated a great impact on health systems. We compared evolution, polypharmacy, and potential drug-drug interactions (P-DDIs) in COVID-19 and non-COVID-19 hospitalizations during first wave of pandemic. Prescriptions for hospitalized patients ≥ 18 years (COVID-19 and non-COVID-19 rooms) between April and September 2020 were included. The computerized medical decision support system SIMDA and the physician order entry system Hdc.DrApp.la were used. Patients in COVID-19 rooms were divided into detectable and non-detectable, according to real-time reverse transcription polymerase chain reaction (RT-PCR). Number of drugs, prescribed on day 1, after day 1, and total; polypharmacy, excessive polypharmacy, and P-DDIs were compared. 1,623 admissions were evaluated: 881 COVID-19, 538 detectable and 343 non-detectable, and 742 non-COVID-19. Mortality was 15% in COVID-19 and 13% in non-COVID-19 (RR [non-COVID-19 vs. COVID-19]: 0.84 [95% CI] [0.66-1.07]). In COVID-19, mortality was 19% in detectable and 9% in non-detectable (RR: 2.07 [1.42-3.00]). Average number of drugs was 4.54/patient (SD ± 3.06) in COVID-19 and 5.92/patient (±3.24) in non-COVID-19 (p<0.001) on day 1 and 5.57/patient (±3.93) in COVID-19 and 9.17/patient (±5.27) in non-COVID-19 (p<0.001) throughout the hospitalization. 45% received polypharmacy in COVID-19 and 62% in non-COVID-19 (RR: 1.38 [1.25-1.51]) and excessive polypharmacy 7% in COVID-19 and 14% in non-COVID-19 (RR: 2.09 [1.54-2.83]). The frequency of total P-DDIs was 0.31/patient (±0.67) in COVID-19 and 0.40/patient (±0.94) in non-COVID-19 (p=0.022). Hospitalizations in the COVID-19 setting are associated with less use of drugs, less polypharmacy and less P-DDIs. Detectable patients had higher mortality.

Simultaneous quantitation of meperidine, normeperidine, tramadol, propoxyphene and norpropoxyphene in human plasma using solid-phase extraction and gas chromatography/mass spectrometry: Method validation and application to cardiovascular safety of therapeutic doses.

RATIONALE: Several opioid analgesics have been related to the prolongation of cardiac repolarization, a condition which can be fatal. In order to establish a correct estimation of the risk/benefit balance of therapeutic doses of meperidine, normeperidine, tramadol, propoxyphene and norpropoxyphene, it was necessary to develop an analytical method to determinate plasma concentrations of these opioids. METHODS: Here we describe a method which incorporates strong alkaline treatment to obtain norpropoxyphene amide followed by a one-elution step solid-phase extraction, and without further derivatization. Separation and quantification were achieved by gas chromatography/electron ionization mass spectrometry (GC/EI-MS) in selected-ion monitoring mode. Quantification was performed with 500 µL of plasma by the addition of deuterated analogues as internal standards. RESULTS: The proposed method has been validated in the linearity range of 25-1000 ng/mL for all the analytes, with correlation coefficients higher than 0.990. The lower limit of quantification was 25 ng/mL. The intra- and inter-day precision, calculated in terms of relative standard deviation, were 2.0-12.0% and 6.0-15.0%, respectively. The accuracy, in terms of relative error, was within a ± 10% interval. The absolute recovery and extraction efficiency ranged from 81.0 to 111.0% and 81.0 to 105.0%, respectively. CONCLUSIONS: A GC/MS method for the rapid and simultaneous determination of meperidine, normeperidine, tramadol, propoxyphene and norpropoxyphene in human plasma was developed, optimized and validated. This procedure was shown to be sensitive and specific using small specimen amounts, suitable for application in routine analysis for forensic purposes and therapeutic monitoring. To our knowledge, this is the first full validation of the simultaneous determination of these opioids and their metabolites in plasma samples.

Meperidine-induced QTc-interval prolongation: prevalence, risk factors, and correlation to plasma drug and metabolite concentrations
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A prolongation of the QTc-interval has been described for several opioids, including pethidine (meperidine). OBJECTIVE: To evaluate in the clinical setting the frequency and risk factors associated with the QT-interval prolongation induced by meperidine. RESEARCH DESIGN AND METHODS: We recruited patients requiring meperidine administration and recorded their medical history and comorbidities predisposing to QT-interval prolongation. Ionograms and electrocardiograms (ECGs) were performed at baseline and during treatment; QT was corrected using the Bazzet, Fridericia, Framinghan, and Hogdes formulas. We measured meperidine and normeperidine by gas chromatography. Values are expressed as mean ± SD (range). RESULTS: 58 patients were studied (43.1% males). All patients received meperidine at a dose of 304 ± 133 (120 - 480) mg/day. Meperidine and normeperidine concentrations were 369 ± 60 (265 - 519) and 49 ± 17 (15 - 78) ng/mL, respectively. Intratreatment control found QTcB 370 ± 30 (305 - 433), QTcFri 353 ± 35 (281 - 429), QTcFra 360 ± 30 (299 - 429), QTcH 359 ± 27 (304 - 427), ΔQTcB +9 ± 42 (-90 to +136), ΔQTcFri +4 ± 45 (-86 to +137), ΔQTcFra +5 ± 40 (-77 to +129), and ΔQTcH +7 ± 40 (-76 to +129) ms. Meperidine concentration correlated with QTc-interval (R > 0.36) and ΔQTc (R > 0.69) but the correlation was even better for normeperidine concentration, QTc (R > 0.52) and ΔQTc (R > 0.81). Depending on the QTc correction formula used, 13 - 15 patients (22.41 - 25.86%) presented ΔQTc values > 30 ms, and 7 - 8 patients (12.07- 13.79%) showed ΔQTc values > 60 ms. Renal failure was associated with risk for ΔQTc > 30 ms of 3.74 (IC95% 1.73 - 8.10) and for ΔQTc > 60 ms of 4.27 (IC 95% 1.26 - 14.48). No patient developed arrhythmias during the study. CONCLUSIONS: Meperidine treatment causes ECG changes (QTc-interval prolongation) in high correlation with normeperidine plasma concentration. Renal failure increases the risk.
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Age-distribution and genotype-phenotype correlation for N-acetyltransferase in Argentine children under isoniazid treatment.

INTRODUCTION: Metabolic clearance of isoniazid (INH) may be up to 10 times faster in individuals who are rapid acetylators compared with slow acetylators. In addition, the acetylation phenotype has been suggested to change with age. A better knowledge of the age distribution of the acetylation genotype and phenotype in children requiring INH for tuberculosis treatment or prevention could be important to optimize safety and efficacy of INH use. OBJECTIVES: The aim of the present study was to evaluate the genotype and phenotype of NAT2 in an Argentinean pediatric population rom Buenos Aires. In addition, we wanted to describe genotype-phenotype correlation, as well as its distribution at different ages. METHODOLOGY: NAT2 genotyping was performed by RFLP technique, searching for common polymorphisms. Acetylisoniazid and isoniazid concentrations were measured by HPLC and NAT2 phenotype was defined from the ratio of both concentrations (Metabolic Ratio, MR). RESULTS: Almost half of the patients (46.02%) possessed wild-type haplotype, with 17.05% of individuals having two fully functional alleles, 57.95% one fully functional allele and 25% with no fully functional allele. According to phenotype, most children (96.59%) were classified as fast acetylators, whereas 1.14% of the cases were intermediate and 2.27% slow acetylators. There was a positive association between age and MR (R = 0.52985, p < 0.000001) with a significant MR difference between age categories (p < 0.001). CONCLUSIONS: We found a high proportion of rapid acetylators compared with other populations. Acetylator phenotype showed a positive correlation with age, with a significant change around the 4th year of life.

Development and Implementation of the Hdc.DrApp.la and SIMDA Programs to Reduce Polypharmacy and Drug-drug Interactions in Patients Hospitalized in Internal Medicine.

OBJECTIVES: We evaluated polypharmacy and possible drug-drug interactions (p-DDIs) in hospitalized patients before and after using the SIMDA Computerized Medical Decision Support System (CMDSS). MATERIALS AND METHODS: We included the prescriptions of ≥ 18 years hospitalized patients in the internal medicine department. We developed and implemented the Hdc.DrApp Physician Order Entry System and the CMDSS SIMDA, which detects p-DDIs and signals dosage adjustment based on renal function. To evaluate the impact of the CMDSS, we made a comparison Before (Survey) / After (Intervention): Survey between Oct/22/2019, and Mar/21/2020, and Intervention between Apr/4/2020 and Sep/3/2020. We analyze prescriptions from the first day and after the first day. We compared the number of drugs, polypharmacy (≥ 5 drugs), excessive polypharmacy (≥ 10 drugs), and p-DDIs. We evaluated differences with the X2 test, Yates correction, Fisher's exact test, ANOVA, and post hoc tests according to their characteristics. RESULTS: We evaluated 2,834 admissions: Survey 1,211 and Intervention 1,623. The number of drugs per patient was 6.02 (± 3.20) in Survey and 5.17 (± 3.22) in Intervention (p < 0.001) on the first day and 9.68 (± 5.60) in Survey and 7.22 (± 4.93) in Intervention (p < 0.001) throughout the hospitalization. Polypharmacy was present in 64% of the Survey and 53% of Interventions (RR: 0.83 (0.78-0.88); and excessive polypharmacy in 14% of the Survey and 10% of Intervention (RR: 0.73, 0.60-0.90). The frequency of total p-DDIs was 1.91/patient (± 4.11) in Survey and 0.35 (± 0.81) in the Intervention (p < 0.001). CONCLUSIONS: We developed and implemented the Hdc.DrApp and SIMDA systems that were easy to use and allowed us to quantify and reduce polypharmacy and p-DDIs.

Precision Medicine in the Renin-Angiotensin System: Therapeutic Targets and Biological Variability.

Pathologies linked to the renin-angiotensin system are frequent, and the drugs used in them are numerous and show great variability in therapeutic effects and adverse reactions. Genetic variants have been detected in the angiotensinogen gene (6), angiotensin-converting enzyme (9), angiotensinconverting enzyme 2 (1), and angiotensin receptor Type 1 (4) among others. However, the large number of studies that have analyzed each of them makes it complex and almost impossible to consider all the existing information. This manuscript aims to review the effects of the different known variants on the expected response of different drugs as a basis for the future development of therapeutic guidelines that seek to implement therapeutic individualization strategies on the renin-angiotensin system.

Dextrophropoxyphene effects on QTc-interval prolongation: Frequency and characteristics in relation to plasma levels.

OBJECTIVE: To evaluate frequency and risk factors for dextropropoxypheneinduced QT-interval prolongation in the clinical setting. DESIGN: Prospective, noninterventional, observational, longitudinal cohort approach. Electrocardiograms were blindly evaluated by independent professionals. SETTING: General ward of a public hospital of metropolitan Buenos Aires. PATIENTS, PARTICIPANTS: Ninety-two patients with indication of receiving dextropropoxyphene for analgesic purposes were included consecutively. All patients finished the study. INTERVENTIONS: All patients were monitored with electrocardiographic controls (previous to drug administration and during steady state) to diagnose and quantify changes in the duration of the QTc interval. MAIN OUTCOME MEASURE: Frequency of drug-induced QTc interval prolongation, QTc interval correlation with plasma drug, and metabolite levels. RESULTS: Ninety-two patients were studied (50 percent males). All patients received a (mean ± SD [range]) dextropropoxyphene dose of 125 ± 25[100-150] mg/d. Dextropropoxyphene and norpropoxyphene concentrations were 112 ± 38[45-199] and 65 ± 33[13-129] ng/mL, respectively. The intra-treatment QTc interval was >450 ms in only one patient (only with the Hodge correction). There were no cases of QTc > 500 ms, and there were no significant differences in the results considering different correction formulas (Bazzet, Fridericia, Framingham, Hodges). Dextropropoxyphene concentrations correlated with QTc (R > 0.45) interval and ΔQTc (R 0.52-0.87), whereas norpropoxyphene correlation was even greater for QTc (R > 0.40-0.64) and ΔQTc (R > 0.47-0.92). Depending on the QTc correction formula, eight patients presented ΔQTc > 30 ms and one patient with ΔQTc > 60 ms. No patient presented arrhythmia during the study. CONCLUSIONS: The authors did not observe a relationship between dextropropoxyphene and QTc interval prolongation at the therapeutic doses used in Argentina.

In vivo Phenotyping Methods: Cytochrome P450 Probes with Emphasis on the Cocktail Approach.

BACKGROUND: Differences in drug response among patients are common. Most major drugs are effective in only 25 to 60 percent of the patients, in part due to the CYP enzymes, whose activity vary up to 50-fold between individuals for some index metabolic reactions. Several factors affect CYP activity, among which genetic polymorphisms have been studied as the major cause for long time. Age, gender, disease states, and environmental influences such as smoking, concomitant drug treatment or exposure to environmental chemicals are also important. METHODS: This article reviews the available literature on multiple phenotypes assessment as an important tool to predict possible therapeutic failures or toxic reactions to conventional drug doses during patient evaluation. RESULTS: Probe drugs can be used in various combinations allowing for the in vivo assessment of multiple pathways of drug metabolism in a single experiment, configuring a new tool known as phenotyping "cocktails". There are several drug cocktails with different advantages and disadvantages. Most of them have sufficient clinical evidence and data validation to support their use in clinical setting as a surrogate for the risk of adverse reaction in the course of therapy, leading to a better balance between efficacy and safety. CONCLUSION: Probes characteristics and metabolic ratio measurements are important in the evaluation of phenotyping cocktails as near-future applications.

Drug-induced QT Interval Prolongation in the Intensive Care Unit.

BACKGROUND: The most common acquired cause of Long QT syndrome (LQTS) is drug induced QT interval prolongation. It is an electrophysiological entity, which is characterized by an extended duration of the ventricular repolarization. Reflected as a prolonged QT interval in a surface ECG, this syndrome increases the risk for polymorphic ventricular tachycardia (Torsade de Pointes) and sudden death. METHOD: Bibliographic databases as MEDLINE and EMBASE, reports and drug alerts from several regulatory agencies (FDA, EMEA, ANMAT) and drug safety guides (ICH S7B, ICH E14) were consulted to prepare this article. The keywords used were: polymorphic ventricular tachycardia, adverse drug events, prolonged QT, arrhythmias, intensive care unit and Torsade de Pointes. Such research involved materials produced up to December 2017. RESULTS: Because of their mechanism of action, antiarrhythmic drugs such as amiodarone, sotalol, quinidine, procainamide, verapamil and diltiazem are associated to the prolongation of the QTc interval. For this reason, they require constant monitoring when administered. Other noncardiovascular drugs that are widely used in the Intensive Care Unit (ICU), such as ondansetron, macrolide and fluoroquinolone antibiotics, typical and atypical antipsychotics agents such as haloperidol, thioridazine, and sertindole are also frequently associated with the prolongation of the QTc interval. As a consequence, critical patients should be closely followed and evaluated. CONCLUSION: ICU patients are particularly prone to experience a QTc interval prolongation mainly for two reasons. In the first place, they are exposed to certain drugs that can prolong the repolarization phase, either by their mechanism of action or through the interaction with other drugs. In the second place, the risk factors for TdP are prevalent clinical conditions among critically ill patients. As a consequence, the attending physician is expected to perform preventive monitoring and ECG checks to control the QTc interval.

Severe neutropenia in a renal transplant patient suggesting an interaction between mycophenolate and fenofibrate.

OBJECTIVE: To describe a patient in whom initiation of micronized fenofibrate precipitated mycophenolate induced neutropenia. CASE SUMMARY: A 57-year-old man was admitted to the hospital because of febrile neutropenia. He had undergone kidney transplantation seventeen years ago. The patient's immunosuppressive maintenance regimen consisted of mycophenolate mofetil (MMF) 500 mg three times a day, and meprednisone 4 mg daily. His medical history included, hypertension treated with losartan 50mg daily, and dyslipidemia treated with ezetimibe 10mg /simvastatin 20mg for four years (until 2 weeks before admission when micronized fenofibrate 200 mg per day was started because of persistently elevated triglycerides levels. On presentation temperature was 37.8°C and initial laboratory tests showed 3130 White Blood Cell Count(WBC)/µL with neutropenia (absolute neutrophil count (ANC) 313/µL) Fenofibrate and mycophenolate mofetil were discontinued, piperacillin tazobactam 4.5gr three times a day and granulocyte stimulation factor 300 µg/day were started. Three days after admission WBC was 7280/µL, neutrophils: 22%, ANC: 1160/mm(3). Mycophenolate mofetil was restarted and granulocyte stimulation factor was discontinued. One month after discharge his WBC was 4480/µL and ANC 1926/µL. DISCUSSION: The initiation of fenofibrate in a patient on stable and therapeutic doses of mycophenolate may have precipitated mycophenolate induced neutropenia, a well described, dose dependent phenomenon. Mycophenolic acid (MPA) displays a complex pharmacokinetic profile susceptible to potential significant interactions with fenofibrate. Since approximately 99% of MPA and fenofibrate bind to albumin, displacement may occur, leading to increased free MPA. Second competition of fenofibric acid for UGT1A9 an enzyme implicated in conjugation of MPA may have decreased its metabolism. The combination of these two effects may increase the risk of dose dependent neutropenia. Using the Interaction Probability Scale (DIPS), the interaction was designated as probable. CONCLUSIONS: Until further evidence is available, when fenofibrate is started in a renal transplant patient on mycophenolate careful monitoring should be considered to avoid potentially fatal complications.

Pharmacovigilance and the cardiovascular system: two sides to every story.

PURPOSE: The objective of the present study was to quantify the reported cardiovascular adverse reactions and adverse reactions to cardiovascular drugs to help to design and implement monitoring and prevention strategies. METHODS: The pharmacovigilance unit (PU) is a peripheral effector of National Pharmacovigilance Center and receives adverse drug reactions notifications from 10 teaching hospitals. Data on adverse reactions beginning in 2004 and notified to the PU were extracted from the database. Cardiovascular adverse drug reactions and adverse reactions to cardiovascular drugs were identified using Medical Dictionary for Regulatory Activities (MedDRA), and the Anatomical Therapeutic Chemical (ATC) Classification System respectively. The reports of adverse reactions were classified according to their seriousness. RESULTS: From 2004 to 2010, 2516 notifications were received (2383 adverse reactions, 106 lack of efficacy, 26 quality failures). These notifications included 151 cardiovascular adverse reactions and 594 adverse reactions caused by cardiovascular drugs. In the first group, of the 151 cardiovascular adverse reactions through MedDRA SOC classification caused by all ATC group classes, 118 (78.2%) were caused by non cardiovascular drugs. Among them antimicrobials (27,2%) and neurologic drugs (21,2%) were the most frequent. 22 (14.6%) adverse reactions were serious. Long QT syndrome, peripheral edema, hypotension, tachycardia, and bradycardia, were the most frequent. In the second group, of the 594 reports identifying adverse reactions involving all MedDRA SOCs but caused only by cardiovascular drugs, 559 reports (94.1%) were non cardiovascular adverse reactions. Enalapril and furosemide accounted for 65.2% there were 33 (5.6%) serious adverse reactions. The most frequent adverse reactions were hyponatremia, impaired renal function, hypokalemia, metabolic alkalosis, asymptomatic elevation of liver enzymes, hyperkalemia, hyperglycemia, edema, and cough. CONCLUSION: Non-cardiovascular adverse reactions were the most frequent manifestation of adverse drug reactions caused by cardiovascular drugs and cardiovascular adverse reactions were most often caused by non cardiovascular drugs. This report highlights the importance of systematic evaluation of adverse drug reactions.

Antihistamines: past answers and present questions.

Antihistamines are drugs frequently used. Several drugs in this family had to be withdrawn from the market or limited in their marketing due to potentially fatal adverse events. These events were related to the ability of some antihistamines to affect cardiac potassium channels and prolong the QT interval with an excessive risk of serious arrhythmias such as Torsades de Pointes (TdP). The presence of arrhythmias in the course of a treatment with antihistamines is essentially dependent on the presence of two factors related to the drugs and other factors related to the patient individual risk. First, the drugs ability to affect potassium channels either at therapeutic or higher doses. Secondly the possibility of interactions with other drugs or natural products resulting in increased plasma concentrations obtained following usual dosage. The drugs mainly involved in interactions are the family of macrolide antibiotics and azole antifungal agents. Among patient-related factor, predisposing genes and co morbid conditions are paramount. This article reviews the characteristics and mechanisms of these interactions and the ability of antihistamines to block different potassium channels. Special consideration is prompted to the existence of genetic polymorphism that affects the kinetics of antihistamines as well as its arrhythmogenic potential. However, the tests for their detection are not widely available and the costs significantly limit their use.

Prokinetic agents and QT prolongation: a familiar scene with new actors.

Prokinetic agents are a very large family of drugs with different mechanisms of action. Only QT prolongation by cisapride has made notable impact and deserved its partial restriction and/or withdrawal from the market. Postmarketing surveillance initially showed that cisapride was generally safe and well tolerated, but in the past decade, more recent data have shown some risk in the patient populations. QT prolongation by prokinetic agents can raised from different mechanisms: some involve increased plasma concentrations of cisapride due to increased bioavailability by inhibiting P glycoprotein, and inhibition of metabolism or deficit in the elimination. On the other hand, pharmacodynamic interactions can also enhance the arrhythmogenic effect of cisapride. The present article presents the mechanisms and reviews the main interactions studied so far, and the role of pharmacovigilance in the detection of rare clinical events. We emphasize the need for physicians to look for conditions (either clinical or not) prone to increase the risk of QT interval prolongation.

Mechanisms of drug induced QT interval prolongation.

The long QT syndrome (LQTS) is characterized by a prolonged QT interval, as well as a propensity to develop syncope and sudden cardiac death caused by the malignant polymorphic ventricular arrhythmia called torsades de pointes (TdP). The QT interval is measured from the onset of the QRS complex to the end of the T wave and can be affected by both ventricular conduction velocities as well as by the velocity of repolarization. In most cases, QT prolongation is caused by factors that prolong the duration of the action potential, mainly by delaying the repolarization phase 3. The molecular mechanism is partially known. There are two well described mechanisms: blocking of the ion channel cavity of HERG; or causing an abnormal protein trafficking required for the location of HERG subunits in cell membrane. Both of them impair the I(Kr) current. However the blockade of ion channels is not the only condition to generate TdP. Other factors may play an important role, e.g. myocardium heterogeneity, drug-drug interaction, genetic polymorphism, and Electrolyte disturbances. Several drugs had been subject of withdrawal because QT-prolongation and arrhythmia. Understanding of processes involved in drug-induced QT prolongation is needed for the study and prevention of life-threatening arrhythmias.

Other drugs acting on nervous system associated with QT-interval prolongation.

Several drugs acting on the nervous system have been implicated in the prolongation of the QT interval. Leaving aside the antidepressant and antipsychotic drugs, some have shown to prolong the QT interval in vivo. These include opioids, particularly methadone, inhalational anesthetics, and some preparations used for treatment of cough. These drugs have a narrow therapeutic interval or possible drug interactions that lead to clinical toxicity manifested by arrhythmias. They share the ability to block potassium channels (HERG), prolong the action potential and QT interval, and generate arrhythmias and Torsades de Pointes like other typicality recognized like antiarrhythmics, antihistamines, prokinetics, psychotropics and anti-infectives agents. Muscle relaxants like alcuronium, pancuronium and atracurium associated with or without atropine prolong significantly the QT interval. Methadone is the opiod most tightly associated with QTc prolongation; with much lesser potency buprenorphine and oxycodone can block HERG channels and depress the IKr current in vitro.Antineoplastic chemotherapy like anthracyclines, alkylating drugs, alkilants and cisplatin are associated with electrocardiographic alterations including prolongation of QT and emesis of different grades. It's very important take in account the synergic effects over the QT prolongation when effective antiemetics like 5-HT3 receptor antagonist (granisetron, ondansetron, and dolasetron) are administered. The Knowledge of their pharmacological properties is of vital importance to avoid exposing particularly vulnerable individuals as those with congenital long QT syndrome, and even the general public to unnecessary risk of potentially fatal arrhythmias.