Possible risk for cardiac arrhythmia related to intravenous erythromycin

Erythromycin prior to endoscopy for acute upper gastrointestinal haemorrhage

BACKGROUND

Upper endoscopy is the definitive treatment for upper gastrointestinal haemorrhage (UGIH). However, up to 13% of people who undergo upper endoscopy will have incomplete visualisation of the gastric mucosa at presentation. Erythromycin acts as a motilin receptor agonist in the upper gastrointestinal (GI) tract and increases gastric emptying, which may lead to better quality of visualisation and improved treatment effectiveness. However, there is uncertainty about the benefits and harms of erythromycin in UGIH.

OBJECTIVES

To evaluate the benefits and harms of erythromycin before endoscopy in adults with acute upper gastrointestinal haemorrhage, compared with any other treatment or no treatment/placebo.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was 15 October 2021.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that investigated erythromycin before endoscopy compared to any other treatment or no treatment/placebo before endoscopy in adults with acute UGIH.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were 1. UGIH-related mortality and 2. serious adverse events. Our secondary outcomes were 1. all-cause mortality, 2. visualisation of gastric mucosa, 3. non-serious adverse events, 4. rebleeding, 5. blood transfusion, and 5. rescue invasive intervention. We used GRADE criteria to assess the certainty of the evidence for each outcome.  MAIN RESULTS: We included 11 RCTs with 878 participants. The mean age ranged from 53.13 years to 64.5 years, and most participants were men (72.3%). One RCT included only non-variceal haemorrhage, one included only variceal haemorrhage, and eight included both aetiologies. We defined short-term outcomes as those occurring within one week of initial endoscopy. Erythromycin versus placebo Three RCTs (255 participants) compared erythromycin with placebo. There were no UGIH-related deaths. The evidence is very uncertain about the short-term effects of erythromycin compared with placebo on serious adverse events (risk difference (RD) -0.01, 95% confidence interval (CI) -0.04 to 0.02; 3 studies, 255 participants; very low certainty), all-cause mortality (RD 0.00, 95% CI -0.03 to 0.03; 3 studies, 255 participants; very low certainty), non-serious adverse events (RD 0.01, 95% CI -0.03 to 0.05; 3 studies, 255 participants; very low certainty), and rebleeding (risk ratio (RR) 0.63, 95% CI 0.13 to 2.90; 2 studies, 195 participants; very low certainty). Erythromycin may improve gastric mucosa visualisation (mean difference (MD) 3.63 points on 16-point ordinal scale, 95% CI 2.20 to 5.05; higher MD means better visualisation; 2 studies, 195 participants; low certainty). Erythromycin may also result in a slight reduction in blood transfusion (MD -0.44 standard units of blood, 95% CI -0.86 to -0.01; 3 studies, 255 participants; low certainty). Erythromycin plus nasogastric tube lavage versus no intervention/placebo plus nasogastric tube lavage Six RCTs (408 participants) compared erythromycin plus nasogastric tube lavage with no intervention/placebo plus nasogastric tube lavage. There were no UGIH-related deaths and no serious adverse events. The evidence is very uncertain about the short-term effects of erythromycin plus nasogastric tube lavage compared with no intervention/placebo plus nasogastric tube lavage on all-cause mortality (RD -0.02, 95% CI -0.08 to 0.03; 3 studies, 238 participants; very low certainty), visualisation of the gastric mucosa (standardised mean difference (SMD) 0.48 points on 10-point ordinal scale, 95% CI 0.10 to 0.85; higher SMD means better visualisation; 3 studies, 170 participants; very low certainty), non-serious adverse events (RD 0.00, 95% CI -0.05 to 0.05; 6 studies, 408 participants; very low certainty), rebleeding (RR 1.13, 95% CI 0.63 to 2.02; 1 study, 169 participants; very low certainty), and blood transfusion (MD -1.85 standard units of blood, 95% CI -4.34 to 0.64; 3 studies, 180 participants; very low certainty). Erythromycin versus nasogastric tube lavage Four RCTs (287 participants) compared erythromycin with nasogastric tube lavage. There were no UGIH-related deaths and no serious adverse events. The evidence is very uncertain about the short-term effects of erythromycin compared with nasogastric tube lavage on all-cause mortality (RD 0.02, 95% CI -0.05 to 0.08; 3 studies, 213 participants; very low certainty), visualisation of the gastric mucosa (RR 1.19, 95% CI 0.79 to 1.79; 2 studies, 198 participants; very low certainty), non-serious adverse events (RD -0.10, 95% CI -0.34 to 0.13; 3 studies, 213 participants; very low certainty), rebleeding (RR 0.77, 95% CI 0.40 to 1.49; 1 study, 169 participants; very low certainty), and blood transfusion (median 2 standard units of blood, interquartile range 0 to 4 in both groups; 1 study, 169 participants; very low certainty). Erythromycin plus nasogastric tube lavage versus metoclopramide plus nasogastric tube lavage One RCT (30 participants) compared erythromycin plus nasogastric tube lavage with metoclopramide plus nasogastric tube lavage. The evidence is very uncertain about the effects of erythromycin plus nasogastric tube lavage on all the reported outcomes (serious adverse events, visualisation of gastric mucosa, non-serious adverse events, and blood transfusion).

AUTHORS' CONCLUSIONS

We are unsure if erythromycin before endoscopy in people with UGIH has any clinical benefits or harms. However, erythromycin compared with placebo may improve gastric mucosa visualisation and result in a slight reduction in blood transfusion.

Amiodarone and acupuncture for cardiac arrhythmia: Study protocol for a systematic review

BACKGROUND

Amiodarone and acupuncture (AA) are commonly used to treat cardiac arrhythmia (CA). The objective of this systematic review is to assess the efficacy and safety of AA for patients with CA.

METHODS

Randomized controlled trials (RCTs) of AA for CC will be searched from 9 databases including PubMed, EMBASE, Cochrane Library, Web of Science, Scopus, Chinese Biomedical Literature Database, China National Knowledge Infrastructure, VIP Information, and Wanfang Data from inception to February 1, 2019 without any limitations. Two reviewers will independently screen the relevant papers, extract data, and evaluate the risk of bias for each included study. RevMan 5.3 software will be used for meta-analysis. The primary outcome includes arrhythmic episodes (including time and frequency domain parameters). The secondary outcomes consist of health-related quality of life, oxygen saturation, and safety.

RESULTS

The protocol of this proposed study will provide evidence to judge whether AA is an effective treatment for patients with CA.

CONCLUSION

The findings of this proposed study will summarize the up-to-date evidence of AA for CA.

PROSPERO REGISTRATION NUMBER

PROSPERO CRD42019120962.

Pathophysiology and Treatment of Gastrointestinal Motility Disorders in the Acutely Ill

Gastrointestinal dysmotility causes delayed gastric emptying, enteral feed intolerance, and functional obstruction of the small and large intestine, the latter functional obstructions being frequently termed ileus and Ogilvie syndrome, respectively. In addition to meticulous supportive care, drug therapy may be appropriate in certain situations. There is, however, considerable variation among individuals regarding what gastric residual volume identifies gastric dysmotility and would encourage use of a promotility drug. While the administration of either metoclopramide or erythromycin is supported by evidence it appears that, dual-drug therapy (erythromycin and metoclopramide) reduces the rate of treatment failure. There is a lack of evidence to guide drug therapy of ileus, but neither erythromycin nor metoclopramide appear to have a role. Several drugs, including ghrelin agonists, highly selective 5-hydroxytryptamine receptor agonists, and opiate antagonists are being studied in clinical trials. Neostigmine, when infused at a relatively slow rate in patients receiving continuous hemodynamic monitoring, may alleviate the need for endoscopic decompression in some patients.

Ventricular Standstill Following Intravenous Erythromycin and Borderline Hypokalemia

Ventricular standstill (VS) is a potentially fatal arrhythmia that is usually associated with syncope, if prolonged and is rarely asymptomatic^[1]. Its mechanism involves either a lack of supraventricular impulse or an interruption in the transmission of these signals from the atria to the ventricles, resulting in a sudden loss of cardiac output^[2]. Although rare, ventricular arrhythmias have been associated with intravenous (IV) erythromycin. However, to our knowledge, VS has not been reported following the administration of IV erythromycin. The Authors describe a rare case of asymptomatic VS and subsequent third-degree atrioventricular block, following the administration of IV erythromycin in a 49-year-old woman with borderline hypokalemia. Through this case, the Authors highlight the importance of cardiac monitoring and electrolyte replacement when administering IV erythromycin, as well as discuss several other mechanisms that contribute to ventricular arrhythmias.

Erythromycin, QTc interval prolongation, and torsade de pointes: Case reports, major risk factors and illness severity

OBJECTIVES

Erythromycin is a macrolide antibiotic that is widely used for various infections of the upper respiratory tract, skin, and soft tissue. Similar to other macrolides (clarithromycin, azithromycin), erythromycin has been linked to QTc interval prolongation and torsade de pointes (TdP) arrhythmia. We sought to identify factors that link to erythromycin-induced/associated QTc interval prolongation and TdP.

METHODS AND RESULTS

In a critical evaluation of case reports, we found 29 cases: 22 women and 7 men (age range 18-95 years). With both oral and intravenous erythromycin administration, there was no significant relationship between dose and QTc interval duration in these cases. Notably, all patients had severe illness. Other risk factors included female sex, older age, presence of heart disease, concomitant administration of either other QTc prolonging drugs or agents that were substrates for or inhibitors of CYP3A4. Most patients had at least two risk factors.

CONCLUSIONS

On the basis of case report evaluation, we believe that major risk factors for erythromycin-associated TdP are female sex, heart disease and old age, particularly against a background of severe illness. Coadministration of erythromycin with other drugs that inhibit or are metabolized by CYP3A4 or with QTc prolonging drugs should be avoided in this setting.

Prokinetics in acute upper GI bleeding: a meta-analysis

BACKGROUND

Recent data suggest that administration of prokinetics before gastroscopy may be useful in patients with acute upper GI bleeding (UGIB). Published studies are limited in the number of subjects evaluated, and the conclusions are disparate.

OBJECTIVE

To assess the evidence of administering prokinetic agents before EGD in acute UGIB.

DESIGN AND SETTING

Comprehensive literature searches from 1990 to January 2010 were performed. We selected for meta-analysis randomized trials assessing prokinetic agents in acute UGIB. The primary outcome was the need for a repeat EGD. Secondary outcomes included endoscopic visualization, blood transfusions, duration of hospitalization, and surgery. Results were reported as odds ratios (ORs) or weighted mean differences (WMDs).

RESULTS

From 487 citations identified, we selected 3 fully published articles and 2 abstracts assessing a total of 316 patients. Erythromycin (3 studies) and metoclopramide (2 studies) were compared with either placebo (2 studies) or no treatment (3 studies). A prokinetic agent significantly reduced the need for repeat EGD (OR 0.55; 95% CI, 0.32-0.94). The number of units of blood was not significantly altered (WMD, -0.40; 95% CI, -0.86 to 0.06) nor was hospital stay (WMD, -1.04; 95% CI, -2.83 to 0.76) or the need for surgery (OR 1.11; 95% CI, 0.27-4.67). Endoscopic visualization was not analyzed because the disparate definitions across studies did not allow for meaningful clinical inferences.

LIMITATIONS

The results are limited by the small number of subjects.

CONCLUSIONS

Intravenous erythromycin or metoclopramide immediately before EGD in acute UGIB patients decreases the need for a repeat EGD, but does not improve other clinically relevant measurable outcomes.

Drug-Induced QTc-Interval Prolongation in the Intensive Care Unit: Incidence and Predictors

There is a paucity of information regarding QTc prolongation in critically ill patients. A prospective observational study was conducted to assess the incidence and predictors of QTc prolongation associated with medications in intensive care unit (ICU) patients. Consecutive adult patients prescribed prespecified QTc-prolonging medications were assessed for development of the combined incidence of QTc >500 ms at anytime and QTc increase >60 ms above baseline. Over 3 months, 200 consecutive patients (63 ± 18 years; 52% female; 73% Caucasian; baseline QTc 447.3 ± 51.5 ms) were evaluated. The primary end point occurred in 48% of the patients (QTc >500 ms 40%, QTc increase >60 ms 29%). The majority of patients experienced a QTc >470 or 450 ms (60.5%). Mean increase in QTc at 48 hours was 20 ± 35 ms. Upon multivariate analysis, length of stay [odds ratio 1.30, 95% confidence interval (1.15, 1.47)] and baseline QTc [1.01 (1.01, 1.02)] were associated with an increased risk for the primary end point, while beta-blockers [0.41 (0.20, 0.81)] were associated with a risk reduction. In conclusion, increased risk of proarrhythmia, as assessed by QTc prolongation, occurs in the majority of ICU patients when prescribed medications with electrophysiologic properties. Increased vigilance is warranted. The possible protective effect of beta-blockers requires confirmation.

Practicalities of nutrition support in the intensive care unit

PURPOSE OF REVIEW

Nutrition support improves clinical outcomes in the critically ill and our understanding of its effects has advanced significantly over the last few years. Three recently published evidence-based guidelines have made generally consistent and thorough recommendations to assist clinicians in providing nutrition support. This review will focus on various aspects of these recommendations, concentrating on the practicalities of nutrition support in the intensive care unit, such as its optimal mode and composition.

RECENT FINDINGS

Enteral nutrition is preferred to parenteral nutrition unless there is a major gut condition which will delay commencement of enteral nutrition. Nasogastric feeding should begin within 24 h, but if intolerance develops, small bowel feeding or pro-motility drugs (erythromycin or metoclopramide) should be attempted before resorting to supplementary parenteral nutrition. Enteral nutrition should not routinely be supplemented with arginine or glutamine, but it should contain a package of eicosapentaenoic acid, gamma-linolenic acid and antioxidants if the patient has acute lung injury or sepsis. Parenteral nutrition should be glutamine supplemented and the prescription should be limited in energy to avoid hyperglycemia. Whether using enteral nutrition or parenteral nutrition, most patients should receive intravenous selenium, and may also need zinc and copper supplementation.

SUMMARY

Intensive care unit patients should have nutrition support based on recent evidence-based guidelines with a preference for nasogastric feeding. If intolerance occurs, pro-motility drugs and small bowel feeding should be attempted. Clinicians should also consider carefully the composition of the nutrition support regimen with regard to lipid content (especially eicosapentaenoic acid and gamma-linolenic acid), antioxidants, glutamine and other micronutrients.

Life-threatening bradyarrhythmia after massive azithromycin overdose

9-month-old infant was inadvertently administered azithromycin 50 mg/kg, taken from floor stock, instead of the prescribed ceftriaxone. Shortly thereafter, she became unresponsive and pulseless. The initial heart rhythm observed when cardiopulmonary resuscitation was started was a widecomplex bradycardia, with a prolonged rate-corrected QT interval and complete heart block. The baby was resuscitated with epinephrine and atropine, but she suffered severe anoxic encephalopathy. Torsade de pointes and QT-interval prolongation have been reported after administration of macrolide antibiotics, including azithromycin, both intravenously and orally. This has occurred especially in the context of coadministered drugs that inhibit the cytochrome P450 (CYP) 3A4 isoenzyme, such as ketoconazole and astemizole. However, bradycardia with complete heart block has not, to our knowledge, been reported specifically with intravenous administration of azithromycin alone, either with therapeutic doses or overdose. Clinicians should be alerted about the potential of azithromycin to cause life-threatening bradycardia, and pharmacy systems should be implemented to ensure special care in the safe administration of this drug, especially when dispensed from a point-of-care source.

Erythromycin infusion prior to endoscopy for acute upper gastrointestinal bleeding: a randomized, controlled, double-blind trial

BACKGROUND/AIM

Presence of clots in the stomach makes emergency endoscopy difficult in patients with upper gastrointestinal bleeding. We investigated whether the association of erythromycin infusion to gastric lavage could improve stomach cleansing before endoscopy.

PATIENTS AND METHODS

One hundred patients admitted for upper gastrointestinal bleeding were randomly assigned to receive either gastric lavage plus intravenous erythromycin (250 mg) or gastric lavage plus placebo before endoscopy in a double-blind study. The primary end point was the efficacy of intravenous erythromycin to improve stomach cleansing before endoscopy, assessed by both subjective and objective criteria.

RESULTS

Characteristics of patients at admission were similar in both groups. Sixty-six patients had portal hypertension. The gastric mucosa was entirely visualized by the endoscopist in 65% of patients in the erythromycin group, versus 44% in the placebo group (p<0.05). The quality of examination of the upper gastrointestinal tract, assessed by using a 10-cm visual analog scale, was better in the erythromycin group (4.2+/-2 vs. 3.3+/-2.2, p<0.05). Clots were found in the stomach in 30% of patients in the erythromycin group, versus 52% in the placebo group (p<0.05). However, ability to identify the source of bleeding, mean duration of endoscopy, and need for a second-look endoscopy, did not differ between the two groups. Similar results were observed in the subgroup of cirrhotic patients. Erythromycin was well tolerated by all patients.

CONCLUSION

Intravenous erythromycin before endoscopy improves stomach cleansing and quality of endoscopic examination in patients with upper gastrointestinal bleeding, but the clinical benefit is limited.

Establishment of enteral nutrition: prokinetic agents and small bowel feeding tubes

PURPOSE OF REVIEW

Nutritional support is vital to improving the clinical outcomes in patients in the intensive care unit. Enteral nutrition should be administered early and aggressively, thereby reducing the need for parenteral nutrition. Because nasogastric feeding is often associated with gastrointestinal intolerance, recent research has focused on the use of prokinetic agents or small bowel feeding tubes to enhance the successful establishment and maintenance of enteral nutrition.

RECENT FINDINGS

Prokinetic agents (such as metoclopramide and erythromycin) improve markers of gastric emptying and appear to improve tolerance of enteral nutrition, although their effects on clinical outcomes are not as well established. In comparison with nasogastric feeding, small bowel feeding allows the dysfunctional stomach of the critically ill to be bypassed, thereby reducing the rate of gastrointestinal complications and probably the risk of pneumonia. Small bowel tubes are more difficult to place than nasogastric tubes, although the new Tiger tube appears very promising.

SUMMARY

Nasogastric feeding is preferred for almost all patients in the intensive care unit. Metoclopramide is the preferred prokinetic agent, although whether it or erythromycin should be administered to all patients in the intensive care unit or only those with gastrointestinal intolerance remains unknown. Small bowel feeding is not currently recommended for all patients in the intensive care unit because the benefits do not appear to outweigh the logistic and cost considerations. Nevertheless, when gastrointestinal intolerance develops in a nasogastrically fed patient, a small bowel feeding tube should be inserted at the earliest opportunity.

Clinical relevance and management of drug-related QT interval prolongation

Much attention recently has focused on drugs that prolong the QT interval, potentially leading to fatal cardiac dysrhythmias (e.g., torsade de pointes). We provide a detailed review of the published evidence that supports or does not support an association between drugs and their risk of QT prolongation. The mechanism of drug-induced QT prolongation is reviewed briefly, followed by an extensive evaluation of drugs associated with QT prolongation, torsade de pointes, or both. Drugs associated with QT prolongation are identified as having definite, probable, or proposed associations. The role of the clinician in the prevention and management of QT prolongation, drug-drug interactions that may occur with agents known to affect the QT interval, and the impact of this adverse effect on the regulatory process are addressed.

Bradycardia associated with intravenous methadone administered for sedation in a patient with acute respiratory distress syndrome

The use of low tidal volumes with permissive hypercapnia in patients with acute respiratory distress syndrome may require heavy sedation to allow them to tolerate mechanical ventilation. Administration of methadone for sedation is an alternative to using other opioids, given its longer elimination half-life and incomplete cross-tolerance with other mu-receptor-active opioids. Methadone appears to have a molecular structure similar to that of verapamil, a calcium channel blocker, and may exhibit similar cardiac properties as well. A 43-year-old man with acute respiratory distress syndrome experienced bradycardia while receiving a continuous infusion of methadone for sedation and mechanical ventilation management. This case report demonstrates that caution is warranted when high dosages of methadone are administered because of its potential cardiac effects.

[Ventricular tachycardia and long QT associated with clarithromycin administration in a patient with HIV infection]

Prolongation of the QT interval is associated with a high risk of serious ventricular tachyarrhythmias, usually torsade de pointes (TdP) polymorphic ventricular tachycardia, although monomorphic ventricular tachycardia may also develop. Both congenital and acquired forms have been reported, acquired forms being much more prevalent. An association between human immunodeficiency virus (HIV) infection and a higher rate of dilated cardiomyopathy has also been recognized. The severity of immunodeficiency seems to influence both the incidence and severity of cardiomyopathy. A higher prevalence of QT prolongation has been reported among hospitalized HIV-positive patients with HIV infection, possibly related to drugs prescribed for such patients or to an acquired form of long QT syndrome arising from HIV infection. We report a case of QT prolongation and development of ventricular arrhythmia in one HIV patient that started with intravenous clarithromycin and cotrimoxazole therapy.

Evaluation of drug-induced QT interval prolongation: implications for drug approval and labelling

Assessment of proarrhythmic toxicity of newly developed drugs attracts significant attention from drug developers and regulatory agencies. Although no guidelines exist for such assessment, the present experience allows several key suggestions to be made and an appropriate technology to be proposed. Several different in vitro and in vitro preclinical models exist that, in many instances, correctly predict the clinical outcome. However, the correspondence between different preclinical models is not absolute. None of the available models has been demonstrated to be more predictive and/or superior to others. Generally, compounds that do not generate any adverse preclinical signal are less likely to lead to cardiac toxicity in humans. Nevertheless, differences in likelihood offer no guarantee compared with entities with a preclinical signal. Thus, the preclinical investigations lead to probabilistic answers with the possibility of both false positive and false negative findings. Clinical assessment of drug-induced QT interval prolongation is crucially dependent on the quality of electrocardiographic data and the appropriateness of electrocardiographic analyses. An integral part of this is a precise heart rate correction of QT interval, which has been shown to require the assessment of QT/RR relationship in each study individual. The numbers of electrocardiograms required for such an assessment are larger than usually obtained in pharmacokinetic studies. Thus, cardiac safety considerations need to be an integral part of early phase I/II studies. Once proarrhythmic safety has been established in phase I/II studies, large phase III studies and postmarketing surveillance can be limited to less strict designs. The incidence of torsade de pointes tachycardia varies from 1 to 5% with clearly proarrhythmic drugs (e.g. quinidine) to 1 in hundreds of thousands with drugs that are still considered unsafe (e.g. terfenadine, cisapride). Thus, not recording any torsade de pointes tachycardia during large phase III studies offers no guarantee, and the clinical premarketing evaluation has to rely on the assessment of QT interval changes. However, since QT interval prolongation is only an indirect surrogate of predisposition to the induction of torsade de pointes tachycardia, any conclusion that a drug is safe should be reserved until postmarketing surveillance data are reviewed. The area of drug-related cardiac proarrhythmic toxicity is fast evolving. The academic perspective includes identification of markers more focused compared with simple QT interval measurement, as well as identification of individuals with an increased risk of torsade de pointes. The regulatory perspective includes careful adaptation of new research findings.

The effects of erythromycin on the electrocardiogram

BACKGROUND

Various cardiac electrophysiologic effects have been attributed to erythromycin. During the course of treating a pneumonia patient with IV erythromycin, the conversion of atrial fibrillation to a sinus rhythm, and its subsequent reversal, appeared to be causally related to the introduction and cessation of this antibiotic.

OBJECTIVE

This observation suggested the need for studying the changes in the ECG following the use of IV erythromycin in a typical clinical setting.

DESIGN

A prospective comparative drug study.

SETTING

A university-affiliated teaching hospital.

PATIENTS

Nineteen patients being treated for uncomplicated community-acquired pneumonia.

INTERVENTION

IV erythromycin, 500 mg, and/or IV cefuroxime, 750 mg, infused in 250 mL of saline over 20 min. In the 11 patients who were receiving both of the antibiotics, cefuroxime was administered immediately before erythromycin was infused.

MEASUREMENTS

The 12-lead ECG measurements were obtained before infusion, at 5-min intervals during each infusion, and at 5 and 10 min after the infusions had been completed. All of the ECG complexes and intervals were measured using a software program (Interpretive Cardiograph; Hewlett Packard; Palo Alto, CA).

RESULTS

The administration of IV erythromycin increased heart rate and prolonged the corrected QT (QTc) interval. These changes were significant at 15 min of the infusion, and were no longer evident 5 min after the infusion had been stopped. The administration of IV cefuroxime did not produce any ECG changes.

CONCLUSIONS

A single, standard dose of IV erythromycin prolongs the QTc interval; therefore, the drug should always be administered as a slow infusion. ECG monitoring should accompany erythromycin therapy in critically ill patients, in patients with electrolyte disorders, or in patients taking other drugs with similar cardiac effects.

Clarithromycin-induced ventricular tachycardia

Clarithromycin is a relatively new macrolide antibiotic that offers twice-daily dosing. It differs from erythromycin only in the methylation of the hydroxyl group at position 6. Although the side-effect profile of erythromycin is established, including gastroenteritis and interactions with other drugs subject to hepatic mixed-function oxidase metabolism, experience with the newer macrolides is still being recorded. Cardiotoxicity has been demonstrated after both intravenous and oral administration of erythromycin but has never been reported with the newer macrolides. We report a case of ventricular dysrhythmias that occurred after six therapeutic doses of clarithromycin. The dysrhythmias resolved after discontinuation of the drug.

Grand Rounds--City Hospital, Nottingham. A complicated case of community acquired pneumonia

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