Extremely prolonged elimination of cibenzoline at toxic plasma concentrations in patients with renal impairments

Combined sepsis- and renal dysfunction-induced hypoglycaemia in an older patient taking cibenzoline

Key Clinical Message

An 86-year-old geriatric patient with sepsis presented cibenzoline-induced hypoglycaemia, although within the boundary range of cibenzoline blood concentration.

Abstract

An 86-year-old geriatric patient taking cibenzoline for ametropic hypertrophic cardiac tendinopathy was admitted to our hospital for the treatment of sepsis. Upon admission, blood cibenzoline levels of 400.1 ng/mL were observed. Antibiotic therapy was initiated and cibenzoline was discontinued. On Day 16, cibenzoline was administered orally at a reduced dose of 50 mg/day. Several days after restarting cibenzoline, the patient developed hypoglycaemia (64 mg/dL), prompting the administration of 20% glucose. The present case demonstrates a rational timeline for cibenzoline administration, considering the patient's renal dysfunction and sepsis. Clinicians should exercise caution when managing older patients with severe infections who are receiving cibenzoline, and should consider the possibility of blood glucose fluctuations regardless of cibenzoline blood levels. Further research is warranted to better understand and address the potential side effects of cibenzoline administration in geriatric populations.

Hypoglycemic Coma Induced by the Use of Succinic Acid Cibenzoline in Frail Late-stage Elderly Subjects

Succinic acid cibenzoline (CZ) is an antiarrhythmic agent often used for the treatment of tachyarrhythmia. However, hypoglycemia should be avoided in the treatment of diabetes. We herein report two late-stage elderly subjects who experienced a severe and prolonged hypoglycemic coma after the usage of CZ. These cases suggest that, when CZ is administered to elderly subjects with renal dysfunction and/or frailty, we should be aware of the possibility that this medicine may induce hypoglycemia and should adjust the dose as appropriate and monitor the concentration of CZ to avoid severe hypoglycemia.

Drug-induced hypoglycaemia: an update

Drugs are the most frequent cause of hypoglycaemia in adults. Although hypoglycaemia is a well known adverse effect of antidiabetic agents, it may occasionally develop in the course of treatment with drugs used in everyday clinical practice, including NSAIDs, analgesics, antibacterials, antimalarials, antiarrhythmics, antidepressants and other miscellaneous agents. They induce hypoglycaemia by stimulating insulin release, reducing insulin clearance or interfering with glucose metabolism. Several drugs may also potentiate the hypoglycaemic effect of antidiabetic agents. Administration of these agents to individuals with diabetes mellitus is of most concern. Many of these drugs, and depending on clinical setting, may also induce hyperglycaemia. Drug-induced hepatotoxicity and nephrotoxicity may lead in certain circumstances to hypoglycaemia. Some drugs may also induce hypoglycaemia by causing pancreatitis. Drug-induced hypoglycaemia is usually mild but may be severe. Effective clinical management can be handled through awareness of this drug-induced adverse effect on blood glucose levels. Herein, we review pertinent clinical information on the incidence of drug-induced hypoglycaemia and discuss the underlying pathophysiological mechanisms, and prevention and management.

Pharmacodynamics of cibenzoline-induced hypoglycemia in rats

Hypoglycemia is one of the serious adverse effects induced by cibenzoline (CBZ), an antiarrhythmic agent. In order to clarify the pharmacodynamics of CBZ-induced hypoglycemia, CBZ was administered intravenously to conscious rats at a dose of 5, 10 or 20 mg/kg and serum samples were collected periodically to determine the concentrations of CBZ, insulin and glucose. The pharmacokinetics of CBZ showed nonlinear characteristics and could be described by a two-compartment model with Michaelis-Menten elimination kinetics. CBZ induced a rapid increase in the serum concentration of insulin. As the CBZ dose was increased, a greater hypoglycemic effect occurred. The indirect response model was applied to account for the CBZ-induced increase in insulin secretion and the subsequent decrease in serum glucose. A linear relationship was assumed between the serum concentration of CBZ and its stimulating effect on insulin secretion. A nonlinear relationship was assumed between the serum concentration of insulin and its stimulating effect on the elimination of serum glucose. The time courses of serum concentrations of CBZ, insulin and glucose after intravenous injection of CBZ could be described by the pharmacokinetic and pharmacodynamic model developed. This approach will be useful for the identification of variable factors related to CBZ-induced hypoglycemia.

Gatifloxacin Induces Augmented Insulin Release and Intracellular Insulin Depletion of Pancreatic Islet Cells

Many hypoglycemic and hyperglycemic episodes associated with clinical use of gatifloxacin (GFLX), a novel fluoroquinolone antimicrobial agent, have been reported in recent years. Some have reported hypoglycemia induced by fluoroquinolones, indicating that these agents may stimulate insulin secretion from pancreatic islet cells. In this study, we investigated the effect of GFLX on insulin homeostasis in islet cells using the insulin secreting cell line, HIT-T15. After 1 h incubation with over 100 microM of GFLX, insulin secretion from the cells was significantly augmented. However, the augmentation of insulin release induced by GFLX subsequently reached a plateau. Coincidentally, cellular insulin was decreased by 120 h incubation, and reactivity to re-stimulation by sulfonylurea was suppressed. The GFLX insulin depletion effect was stronger than the effects produced by such other fluoroquinolones as levofloxacin and ciprofloxacin. This study suggests that GFLX should induce insulin oversecretion from pancreatic islet cells in the short-term, and decrease insulin productivity or increase insulin disintegration in the long-term. These results are consistent with the clinical results of GFLX finding that hypoglycemic episodes were seen after a first single administration, and most hyperglycemic episodes were seen more than 2 d after the start of administration.

Symptomatic hypoglycemia in a patient with chronic hemodialysis

We describe the case of a 71-years-old man in chronic hospital hemodialysis who was admitted to the hospital because of symptomatic hypoglycemia. We discovered that this was due to a documented intoxication with cibenzoline, an antiarrhythmic drug, used to treat (supra-)ventricular tachyarrhythmia. In addition we made a short review of the literature concerning cibenzoline intoxication.

Heart Failure Elevates Serum Levels of Cibenzoline in Arrhythmic Patients

BACKGROUND

Cibenzoline dosing is generally based on renal function, but serum concentrations might be greater than the expected therapeutic levels when standard oral dosing is used. Because heart failure might modify cibenzoline pharmacokinetics, the difference in cibenzoline pharmacokinetics between patients with and without heart failure was evaluated.

METHODS AND RESULTS

The study enrolled 368 patients (233 men, 135 women) that had been hospitalized and received cibenzoline therapy at the National Cardiovascular Center from January 2001 to May 2005. There were 89 patients with heart failure (51 men, 38 women) and 279 patients without heart failure (182 men, 97 women). They had therapeutic drug monitoring > or = 3 days after the beginning of treatment with cibenzoline. Brain natriuretic peptide (BNP) was measured in 81 patients (50 men, 31 women) concurrently with therapeutic drug monitoring of cibenzoline. The difference in serum cibenzoline concentration/(dose/weight) (C/D) values between patients with and without heart failure was analyzed using analysis of covariance (ANCOVA) with creatinine clearance (Ccr) serving as the covariate. The effects of dose/weight and the log-transformed BNP (log-BNP) values on serum cibenzoline concentrations were also assessed using ANCOVA. There were 135 and 361 measurements of serum cibenzoline concentration in patients with and without heart failure, respectively. Pearson's correlation coefficient analyses in the patients with and without heart failure revealed that the C/D values were significantly correlated with Ccr (with heart failure, y = -0.837x + 169, r = -0.211, p = 0.014; without heart failure, y = -0.789x + 132, r = -0.393, p < 0.001), and the ANCOVA model indicated that C/D values were significantly higher in patients with heart failure than without heart failure. The ANCOVA model also showed that dose/weight, Ccr and the log-BNP value were significant factors.

CONCLUSIONS

The selection of a cibenzoline dose based only on renal function may increase the risk of toxicity in patients with heart failure. Cardiac function should be taken into account in cibenzoline dosing. The log-BNP may be a useful index for predicting serum cibenzoline concentrations.