Oral erythromycin and the risk of sudden death from cardiac causes

BACKGROUND

Oral erythromycin prolongs cardiac repolarization and is associated with case reports of torsades de pointes. Because erythromycin is extensively metabolized by cytochrome P-450 3A (CYP3A) isozymes, commonly used medications that inhibit the effects of CYP3A may increase plasma erythromycin concentrations, thereby increasing the risk of ventricular arrhythmias and sudden death. We studied the association between the use of erythromycin and the risk of sudden death from cardiac causes and whether this risk was increased with the concurrent use of strong inhibitors of CYP3A.

METHODS

We studied a previously identified Tennessee Medicaid cohort that included 1,249,943 person-years of follow-up and 1476 cases of confirmed sudden death from cardiac causes. The CYP3A inhibitors used in the study were nitroimidazole antifungal agents, diltiazem, verapamil, and troleandomycin; each doubles, at least, the area under the time-concentration curve for a CYP3A substrate. Amoxicillin, an antimicrobial agent with similar indications but which does not prolong cardiac repolarization, and former use of erythromycin also were studied, to assess possible confounding by indication.

RESULTS

The multivariate adjusted rate of sudden death from cardiac causes among patients currently using erythromycin was twice as high (incidence-rate ratio, 2.01; 95 percent confidence interval, 1.08 to 3.75; P=0.03) as that among those who had not used any of the study antibiotic medications. There was no significant increase in the risk of sudden death among former users of erythromycin (incidence-rate ratio, 0.89; 95 percent confidence interval, 0.72 to 1.09; P=0.26) or among those who were currently using amoxicillin (incidence-rate ratio, 1.18; 95 percent confidence interval, 0.59 to 2.36; P=0.65). The adjusted rate of sudden death from cardiac causes was five times as high (incidence-rate ratio, 5.35; 95 percent confidence interval, 1.72 to 16.64; P=0.004) among those who concurrently used CYP3A inhibitors and erythromycin as that among those who had used neither CYP3A inhibitors nor any of the study antibiotic medications. In contrast, there was no increase in the risk of sudden death among those who concurrently used amoxicillin and CYP3A inhibitors or those currently using any of the study antibiotic medications who had formerly used CYP3A inhibitors.

CONCLUSIONS

The concurrent use of erythromycin and strong inhibitors of CYP3A should be avoided.

Serum sickness like illness and antimicrobials in children

AIM

To determine which antimicrobials are associated with the development of serum sickness like reactions in children admitted to hospital in Christchurch.

METHOD

A retrospective case note review of children admitted with serum sickness like reactions over a 10 year period was carried out. 59 children were identified and 30 of these were eligible for inclusion in the study.

RESULTS

Of the 30 children with serum sickness like reaction, 19 had received cefaclor alone, six penicillin V, two amoxycillin, and one each flucloxacillin cotrimoxazole and triacetylolendomycin (TAO). Children received these antimicrobials for 3-10 days.

CONCLUSION

In this study cefaclor was commonest antimicrobial agent associated with the development of serum sickness like reaction. This association should receive consideration prior to prescribing cefaclor to children.

[A new cause of torsades de pointes: combination of terfenadine and troleandomycin]

The authors report a case of wave-burst arrhythmia which occurred during combined treatment with terfenadine and troleandomycin. After the treatment had been stopped and the QT interval returned to normal, terfenadine treatment was reintroduced with no major change in repolarization. However, as soon as troleandomycin was associated, there was a significant and progressive prolongation of QT. Normal repolarization was restored again with troleandomycin alone. These findings suggest drug interaction between terfenadine and troleandomycin. Although it is not possible to carry out serum assays of terfenadine, one possible physiopathological hypothesis would be an overdose of terfenadine. Terfenadine undergoes hepatic oxidative metabolism involving the cytochrome P450 pathway and troleandomycin inhibits cytochrome P450. In the literature, a case has already been described of wave-burst arrhythmia related to terfenadine overdose when associated with a cytochrome P450 inhibitor.

Efficacy and safety of low-dose troleandomycin therapy in children with severe, steroid-requiring asthma

BACKGROUND

Troleandomycin (TAO), a macrolide antibiotic, was studied as an alternative treatment in 18 children with severe, steroid-requiring asthma.

METHODS

In this investigation three treatment arms were used in randomized, double-blind, parallel fashion: combination TAO and methylprednisolone (MPn), combination TAO and prednisone, and MPn alone.

RESULTS

All groups tolerated a considerable reduction in glucocorticoid dose over the 12 weeks of the study: 80% +/- 6% for TAO-MPn, 55% +/- 8% for TAO-prednisone, and 44% +/- 14% for MPn alone. These reductions are all statistically significant (p < 0.05) within groups, and the differences between groups were statistically significant between the TAO-MPn and MPn alone groups. The concentration of methacholine required to induce a 20% decrease in forced expiratory volume in 1 second and pulmonary function were not significantly improved in any treatment group. Safety parameters including blood chemistry and hematology, adrenal function assessment; bone densitometry, and muscle strength testing, were not altered significantly. Two patients who received TAO had elevated liver enzyme levels; one required discontinuation of TAO and one experienced spontaneous resolution without intervention. Lack of statistically significant changes in the efficacy parameters were likely a result of small sample size and effects of the glucocorticoid dose taper.

CONCLUSIONS

TAO is safe and may be a reasonable treatment alternative in a limited trial for patients who are unable to tolerate tapering of their glucocorticoid dosage. Therapy should be guided by the goal of treatment, that is, glucocorticoid dose reduction or improvement of pulmonary function with appropriate monitoring of pulmonary function and adverse effects.

A double-blind study of troleandomycin and methylprednisolone in asthmatic subjects who require daily corticosteroids

A group of 75 subjects with asthma requiring daily corticosteroids for control were enrolled in a 2-yr, double-blind, placebo-controlled study of the use of troleandomycin combined with methylprednisolone, compared with methylprednisolone alone, for the management of their asthma. The primary outcome variables were determination of the lowest stable methylprednisolone dose and assessment of corticosteroid side effects. Methylprednisolone dose was adjusted to maintain optimal control of asthma symptoms. A total of 30 patients receiving TAO and 27 patients receiving placebo completed 1 yr; 17 on TAO and 8 on placebo completed 2 yr of double-blind participation. Control of asthma was equivalent in both groups. The vast majority of patients in both groups achieved alternate-day dosing (29 of 30 on TAO and 23 of 27 on placebo in the first year). The lowest stable doses of methylprednisolone achieved were 10.4 mg/day (placebo) versus 6.3 mg/day (TAO) in the 1-yr group (p = 0.03). However, the baseline dose was also significantly higher in the placebo group (22.8 versus 17.6 mg/day in the TAO group). Therefore, the reductions in methylprednisolone dose were not significantly different between treatment groups. Differences were observed between the two treatment groups in serum IgG, fasting blood sugar, serum cholesterol, and progression of osteoporosis. In each instance the more unfavorable response occurred in those subjects receiving TAO. We conclude that the addition of TAO to methylprednisolone was not accompanied by a reduction in corticosteroid side effects compared with treatment with methylprednisolone alone. Furthermore, no evidence was found for a subset of "TAO responders."(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-inflammatory drugs in the treatment of allergic disease

The treatment of asthma is undergoing significant change with an emphasis on anti-inflammatory therapy. While glucocorticoids are the most potent anti-inflammatory agent, certain patients fail to respond. These patients may be candidates for alternative anti-inflammatory therapy, such as troleandomycin, methotrexate, gold, hydroxychloroquine, or dapsone. In addition, the application of immunomodulator therapy, such as intravenous gamma globulin or cyclosporine, may be useful.

Benefits and complications of troleandomycin (TAO) in young children with steroid-dependent asthma

In nine children with steroid-dependent asthma, ranging in age from 2 and 11/12 to 14 and 4/12 years, troleandomycin (TAO) was administered at a dose of 250 mg po QD or BID, along with oral methylprednisolone. Both medications were then rapidly changed to a QOD schedule. Baseline daily steroid dosage requirements decreased from 15.3 +/- 9.1 mg methylprednisolone to 1.4 +/- 0.7 mg (P less than 0.01, paired t-test), and the number of steroid bursts (1-2 mg/kg/day) per year decreased from 12.2 +/- 4.8 to 4.1 +/- 2.0 (P less than 0.01, paired t-test). There was also a significant decrease in the number of hospitalizations per year from 3.4 +/- 4.6 to 0.6 +/- 0.7 (P less than 0.05, paired t-test). The incidence of steroid side effects increased, despite the decrease in the amount of steroid required. Specifically, the prevalence of cataracts increased from 11% to 33% (chi 2 = 4.5, P = 0.15) and the prevalence of hypercholesterolemia increased from 22% to 78% (chi 2 = 16.67, P less than 0.001). There was no elevation of serum transaminases in any of our patients on TAO. Although TAO appears to be efficacious, caution is warranted when TAO is considered for use in younger children with steroid-dependent asthma.

Effect of low-dose troleandomycin on glucocorticoid pharmacokinetics and airway hyperresponsiveness in severely asthmatic children

Fifteen hospitalized asthmatic children (8 to 18 years old) completed a 2-week randomized, parallel, double-blind placebo-controlled comparison of combination methylprednisolone and placebo troleandomycin, prednisone and troleandomycin (P-TAO) or methylprednisolone-TAO (MPn-TAO). Troleandomycin (250 mg once daily or every other day) and glucocorticoid doses were reduced by a standard protocol. Symptom scores, blood chemistries, pulmonary function tests, airway response to methacholine, and glucocorticoid pharmacokinetics were compared. In each group, a steroid dose reduction of 50% was achieved without a deterioration in symptom scores. Methacholine response was unchanged in all five on methylprednisolone alone, but decreased 3-fold to 30-fold in two of five on combination P-TAO, and four of five on combination MPn-TAO. Troleandomycin decreased MPn clearance by an average of 62% but did not alter prednisolone clearance. Low-dose TAO combined with MPn has a significant effect on methylprednisolone clearance in children, an effect equivalent to that reported with higher dose TAO (1000 mg/d) therapy. In addition, this preliminary study suggests that TAO may decrease bronchial hyperresponsiveness to methacholine in severely asthmatic children.

Fatal varicella in a corticosteroid-dependent asthmatic receiving troleandomycin

Long-term use of corticosteroids (CSs) may result in an increased risk of disseminated varicella. Concurrent administration of troleandomycin (Tao) to treat CS-dependent asthmatics can potentiate steroid effects. We present the first case of fatal varicella in a patient concurrently receiving methylprednisolone and Tao therapy. At the time of her death she had been receiving CSs for 2 years and Tao for 1 year. She had a 2-day history of fever, lower back and abdominal pain, dysuria, and constipation. Later, when pox lesions were evident, it was learned she had been exposed to varicella 2 weeks previously. While hospitalized she developed hepatitis, gastrointestinal hemorrhage, disseminated intravascular coagulopathy, and pneumonitis, resulting in respiratory failure. She succumbed despite treatment with stress doses of steroids, intravenous acyclovir, fresh frozen plasma, and ventilatory support. Autopsy findings revealed evidence consistent with disseminated varicella. This case suggests that concurrent therapy with CSs and Tao may increase the risk for disseminated varicella, possibly by enhancing CS-induced immunosuppressive effects. We suggest that other immunologic parameters in addition to serum varicella titers might be helpful in identifying those CS-dependent patients at risk. Any CS-dependent asthmatic, whether or not receiving Tao, should receive varicella-zoster immune globulin within 96 hours of exposure and acyclovir once varicella is clinically apparent. Varicella vaccine should be considered for those not yet exposed.

[Psychotic disorders linked to the inhibition of benzodiazepine catabolism]

Five clinical cases of interaction between benzodiazepines on one hand and erythromycin, troleandomycin, josamycin and cimetidine on the other hand have been analyzed. These interactions resulted in severe disorders of behaviour, amnesia (including amnesia-automatism syndrome in one case), disturbances of consciousness and withdrawal syndrome. These disorders were consecutive to inhibition of the hepatic cytochrome P-450 system. Practical means of avoiding this risk consists in limiting such drug combinations, reducing benzodiazepine dosage and, if a combined treatment is necessary, using by preference either benzodiazepines degraded by conjugation instead of oxidation, or macrolides, or anti-H2 compounds with reduced inhibitory effect on microsomes.

Prolonged cholestasis after troleandomycin-induced acute hepatitis

We report the case of a patient in whom troleandomycin-induced hepatitis was followed by prolonged anicteric cholestasis. Jaundice occurred after administration of troleandomycin for 7 days and was associated with hypereosinophilia. Jaundice disappeared within 3 months but was followed by prolonged anicteric cholestasis marked by pruritus and high levels of alkaline phosphatase and gammaglutamyltransferase activities. Finally, pruritus disappeared within 19 months, and liver tests returned to normal 27 months after the onset of hepatitis. This observation demonstrates that prolonged cholestasis can follow troleandomycin-induced acute hepatitis.

An improved protocol for the use of troleandomycin (TAO) in the treatment of steroid-requiring asthma

An improved protocol was developed for the use of troleandomycin (TAO) in severe, steroid-requiring subjects with asthma. Compared to previous reports, this protocol uses a lower starting dose of TAO and a rapid steroid taper. Fifteen patients were treated with TAO following the new guidelines. Steroid requirements in the 15 patients dropped by 68% within 2 weeks, and 13 of the 15 patients were able to be maintained on alternate day steroids. In spite of rapid steroid taper, both FEV1 and mean FVC increased significantly (p less than 0.001). There was a low incidence of side effects and, in contrast to previous reports on TAO, no patient had even a transient increase in cushingoid appearance. Glucose intolerance was observed initially in three patients but resolved with continued steroid taper. Transient liver-enzyme elevation was noted in four patients and in each case reversed with a reduction in TAO dosage. The revised protocol is associated with an improved risk-benefit ratio. New guidelines are presented for the use of TAO in severe steroid-requiring subjects with asthma.

Drug interactions and hepatitis produced by some macrolide antibiotics

Drug interactions involving macrolides have been mainly reported in subjects receiving troleandomycin and in a few receiving erythromycin derivatives. In rats and in humans, troleandomycin, erythromycin and erythromycin derivatives induce microsomal enzymes; the induced isozymes of cytochrome P-450 have a high activity for these macrolides but a poor activity with several other substrates. These isozymes actively demethylate and oxidize these macrolides into nitrosoalkanes which form stable, inactive complexes with the iron of cytochrome P-450. Eventually, the oxidative metabolism of other drugs may be decreased. These effects are marked after administration of troleandomycin, moderate after administration of erythromycin derivatives and absent (or negligible) after administration of spiramycin, josamycin or midecamycin. A second adverse effect of the administration of troleandomycin or erythromycin derivatives is the possible occurrence of hepatitis. Mild hepatic dysfunction is fairly frequent and may be toxic in type. In contrast, jaundice is common, is frequently associated with hypersensitivity, and promptly recurs when the drug is readministered. Troleandomycin and erythromycin derivatives, which form nitrosoalkanes, produce hepatitis, whereas josamycin, midecamycin and spiramycin, which do not form cytochrome P-450-nitrosoalkane complexes, rarely, if ever, produce hepatitis. Nitrosoalkanes are unstable intermediates which react with glutathione but also with cysteine and might covalently bind to the SH-groups of proteins. The following mechanism might be proposed as a hypothetical attempt to link up these various observations. The macrolide (or its reactive metabolite) may have discrete toxicity; in several subjects, this may produce minor liver lesions and a mildly raised aminotransferase activity. Necrosis of a few hepatocytes may release into the circulation plasma membrane proteins altered by the covalent binding of metabolites. Such modified liver antigens may be recognized as foreign and may trigger, in an exceptional subject, an immunoallergic type of clinical hepatitis.

Methylprednisolone and troleandomycin in treatment of steroid-dependent asthmatic children

Oral methylprednisolone combined with troleandomycin has been reported to be successful in treating poorly controlled, severe asthma in adults. We found this drug combination to be effective in treating 11 steroid-dependent children with poorly controlled asthma who were aged 7 to 13 years, for 12 to 28 months. Improvement of clinical and pulmonary functions was achieved within seven days, with the forced expiratory volume in 1 s increasing by 38% and the maximal midexpiratory flow rate increasing by 55% over the baseline value. By one year, the former improved to 98% of predicted value and the latter, to 79% of predicted value. Compared with the prior 12 months, patients at this time required fewer emergency visits, missed fewer days of school, and had fewer hospitalizations. Side effects included transient-increased cushingoid features, abdominal pain, and liver enzyme level elevation. Patients showed less evidence of adrenal suppression.

[A case of icterus during treatment with triacetyloleoandomycin as sole therapy]

A case of jaundice is reported, which was eventually ascribed to TAO alone, once infectious, viral, neoplastic . . . causes were outruled. For specific reasons, high doses of this antibiotic had been required. The physiopathology is discussed; allergy is dismissed. The product's hepatotoxicity in high doses is considered. Although pathological evidence is lacking, this hypothesis is supported by the occurrence of rapid and complete resolution once therapy was discontinued. Specific characteristics of the jaundice are also pointed out: mildness and occurrence after a long interval. This brief paper is by no means designed to disparage TAO, but is meant to monitor, as far as possible, its dosage.

Efficacy of troleandomycin in outpatients with severe, corticosteroid-dependent asthma

Sixteen severe, corticosteroid-dependent yet resistant outpatient asthmatics were treated with troleandomycin (TAO), a macrolide antibiotic, in an attempt to both induce a clinical remission and reduce methylprednisolone requirements. Within the first 2 wk of initiating TAO therapy, 50% of the patients experienced a greater than 20% increase in forced expiratory volume in 1 sec (FEV1) and 80% noted a greater than 20% increase in forced vital capacity between 25% and 75% (FVC 25%-75%). Maximal increases in FEV1 and FVC 25%-75% were noted in all patients within the first 6 wk on TAO and methylprednisolone. There was a concomitant clinical improvement in all patients. Corticosteroid-induced side effects, gastrointestinal tract discomfort, and elevated serum glutamic pyruvic transaminase (SGPT) were common yet generally transient during TAO and methylprednisolone therapy. After a 4- to 18-mo follow-up 15/16 patients were well-controlled on TAO and methylprednisolone. Methylprednisolone requirements were reduced at least four- to fivefold in most patients during TAO therapy. Normal morning serum cortisol levels were documented after varying intervals in most patients when both TAO (250 mg) and methylprednisolone (4 to 16 mg) could be reduced to alternate-day administration. Only one patient was forced to discontinue therapy due to side effects. The present study extends the effectiveness of TAO therapy to ambulatory asthmatics, establishes a clinical strategy that maximizes benefit/risk factors, and provides practical guidelines for the long-term use of TAO and methylprednisolone.

Carbamazepine intoxication due to triacetyloleandomycin administration in epileptic patients

In 17 epileptics receiving carbamazepine (CBZ) alone or in combination with other anticonvulsant drugs, administration of triacetyloleandomycin (Tri A) led to an acute and unexpected intoxication (drowsiness, nausea, vomiting, and dizziness). Similar symptoms occurred again in 3 patients after Tri A was administered a second time. The same toxic manifestations were observed in two patients receiving CBZ and erythromycin. A rapid increase in plasma levels of CBZ occurred after institution of Tri A therapy in 6 patients, the CBZ levels quickly returning to normal after withdrawal of Tri A. Thus, it is suggested that the observed intoxication is due to the simultaneous administration of CBZ and Tri A (or erythromycin). The possible role of hepatic dysfunction in this syndrome of intoxication is discussed. Furthermore, the intoxication may be at least partially related to serum electrolyte disturbances, as suggested by one case in which obvious signs of water intoxication were detected. The severity and frequency of intoxication should lead to proscribing Tri A or other macrolide antibiotics in patients receiving CBZ.

Ergotism with therapeutic doses of ergotamine tartrate

Two cases of acute ergotism are described in patients taking therapeutic oral doses of ergotamine tartrate and concomitant triacetyloleandomycin. Both showed satisfactory response to infusion of sodium nitroprusside with normal perfusion being obtained in the affected limbs. The treatment of ergotism with sodium nitroprusside is reviewed and the apparent interaction of ergotamine and triacetyloleandomycin is discussed.

The use of triacetyloleandomycin in skin and soft tissue infections: results of a New Zealand general-practitioner multi-centre trial

Fifty-one New Zealand general practitioners observed the treatment of 137 cases of skin and soft tissue infections with triacetyloleandomycin (TAO, Pfizer) over a five-month period. Nearly a third of these lesions occurred in children aged 10 years or less. "Excellent" or "good" results in 129 cases (94.2 percent) confirmed triacetyloleandomycin to be generally effective in these conditions. Twice-daily (12-hourly) oral administration proved as effective as more frequent dosage regimens and no major side-effects were encountered. Twenty cases with associated minor surgery are discussed separately.

[Is triacetyl oleandomycin-ergotamine tartrate combination dangerous?]

The authors report a case of ischaemia of all four limbs in an adolescent following the simultaneous ingestion of triacetyl oleandomycin and ergotamine tartrate in low dosage. Two cases involving this same association of medications have appeared in the literature and attention is therefore drawn to the possible danger of use of these two drugs together.