Severe Hypoglycemia Associated with Use of Trimethoprim/Sulfamethoxazole in a Patient with Chronic Renal Insufficiency

Dose Dependent Effect of Sulfamethoxazole on Inhibiting KATP Channel of Mouse Pancreatic β Cell

Sulfamethoxazole (SMX) is widely used as an antibiotic in the clinical application with side effects of hypoglycemia. This is because SMX contains the sulfonamide structure, which closes ATP-sensitive potassium (KATP) channels and induces insulin secretion. However, there are no detail reports that measure the effective dose that can close KATP channels and induce insulin secretion. In this study, whole-cell patch clamp recording was utilized to measure the effect of SMX on KATP channel activity on pancreatic β cells. Also, the static incubation assay with mice islets was assessed to measure the insulin secretion capacity of SMX. SMX was shown to inhibit the KATP channel in pancreatic β cell membrane and induce insulin secretion in relatively high concentration. The half maximal inhibitory concentration (IC50) for KATP channel activity of SMX was .46 ± .08 mM. It was also shown that a near IC50 concentration of SMX (.5 mM) was able to nearly fully block the KATP channel when simultaneously applied with low concentration sulfonylurea, tolbutamide (.01 mM). Our present data provide important information for the clinical use of SMX to treat infection in diabetic patients using sulfonylureas.

Trimethoprim-sulfamethoxazole-induced refractory hypoglycaemia successfully treated with octreotide

Trimethoprim-sulfamethoxazole (TMP-SMX) is a commonly prescribed antimicrobial agent for a wide variety of infections. It is generally well tolerated in a majority of patients; however, serious adverse effects have been described with its usage. Hypoglycaemia is an exceedingly rare but potentially life-threatening side effect of this antimicrobial agent due to its sulfonylurea-like effect. We describe a case of symptomatic, refractory hypoglycaemia secondary to TMP-SMX in a patient being treated for Stenotrophomonas maltophilia bacteraemia, which required treatment with 10 hours of intravenous dextrose (including several 50% dextrose boluses), as well as intramuscular glucagon and octreotide. We reviewed previous case reports described in the literature of TMP-SMX-induced hypoglycaemia, in which renal insufficiency was noted to be a common predisposing risk factor in an overwhelming majority of cases. In refractory cases of TMP-SMX-induced hypoglycaemia, intravenous octeotride may be considered for treatment.

Impact of drugs on hypoglycaemia in hospitalised patients

Objectives

Hospital admission rates for hypoglycaemia now exceed those for hyperglycaemias among older adults. A growing number of reports associating hypoglycaemia with non-antidiabetic drugs have been published. Clinical pharmacists are often faced with hypoglycaemia in patients taking multiple medications. This study assessed the potential relationship between prescribed drugs and episodes of hypoglycaemia during hospitalisation.

Methods

Point-of-care blood glucose values and prescribed drugs were analysed in patients admitted to a regional hospital. Hypoglycaemia cases were defined as patients with at least one hypoglycaemic event (random glucose value ≤3.9 mmol/L), and normoglycaemic cases as those with random glucose concentrations within the range of 4.5-5.8 mmol/L. Analyses were carried out using multivariate logistic regressions and Cox proportional hazard models.

Results

373 patients (53% males; median age=74 years) were included in the analysis and of these, 64 (17%) had at least one hypoglycaemic event. Patients who experienced a hypoglycaemic event had a longer length of stay (median=10 vs 7 days, p<0.01) and a higher rate of antidiabetic drugs prescription (83% vs 37%, p<0.01). The number of non-antidiabetic drugs was associated with an increased risk of hypoglycaemia during hospitalisation (HR 2.3, 95% CI 1.4 to 4, p<0.01). After adjusting by confounders, heparin and pantoprazole were found to be associated with hypoglycaemia.

Conclusions

The relationship between hypoglycaemia and polypharmacy reinforces the advice to limit polymedication as much as possible, especially in elderly patients. This result underlines the potential involvement of clinical pharmacists with the aim to reduce the risk of hypoglycaemia during hospitalisation.

Symptomatic Hypoglycemia Associated with Trimethoprim/Sulfamethoxazole and Repaglinide in a Diabetic Patient

Objective

To report a case of clinically significant hypoglycemia attributed to the concomitant use of trimethoprim/sulfamethoxazole (TMP/SMX) and repaglinide by a diabetic patient.

Case summary

A 76-year-old diabetic patient with impaired renal function and no history of hypoglycemia was receiving treatment with repaglinide 1 mg 3 times daily. Five days after TMP/SMX therapy was started for a urinary tract infection, the man developed symptomatic hypoglycemia. Repaglinide and TMP/SMX were stopped and intravenous d-glucose was administered to normalize glucose levels. Repaglinide, but not TMP/SMX, was reintroduced 5 days later and no other hypoglycemic episode occurred. Objective causality assessments revealed that the interaction was probable (World Health Organization-Uppsala Monitoring Centre) or possible (Horn Drug Interaction Probability Scale).

Discussion

This interaction between TMP/SMX and repaglinide was predictable according to available pharmacokinetic data in healthy subjects. Trimethoprim induced CYP2C8 inhibition, thus increasing the plasma concentration of repaglinide. This interaction is mentioned in the repaglinide product information. To our knowledge, however, no case of symptomatic hypoglycemia associated with a combination of repaglinide and trimethoprim has been described before. This discrepancy may be explained by the subtherapeutic dosage used in the pharmacokinetic study. Moreover, our patient had impaired renal function, which may have led to trimethoprim accumulation and potentiated its interaction with repaglinide. A direct lowering of blood glucose levels due to sulfamethoxazole, also potentiated by renal failure, could also be involved in triggering hypoglycemia.

Conclusions

This interaction between TMP/SMX and repaglinide may have involved inhibition of CYP2C8 by trimethoprim. Clinicians should be aware that this association may lead to symptomatic hypoglycemia, particularly in patients with renal dysfunction.

Severe co-trimoxazole-induced hypoglycaemia in a patient with microscopic polyangiitis

A 69-year-old man presented to the emergency department with lower respiratory tract infection and febrile neutropaenia. He was recently discharged following a 50-day hospital stay with newly diagnosed microscopic polyangiitis, complicated by pulmonary haemorrhage and severe renal dysfunction requiring renal replacement therapy, plasma exchange and immunosuppression (cyclophosphamide and methylprednisolone). High risk of pneumocystis pneumonia (PCP) led to an escalation in treatment from prophylactic to therapeutic oral co-trimoxazole, alongside broad-spectrum antibiotics. The patient suffered from severe and protracted hypoglycaemia, complicated by a tonic-clonic seizure 7 days after escalation to therapeutic co-trimoxazole. Endogenous hyperinsulinaemia was confirmed and was attributed to co-trimoxazole use. Hypoglycaemia resolved 48 hours after discontinuation of co-trimoxazole. PCP testing on bronchoalveolar lavage was negative. Owing to the prescription of heavy immunosuppression in patients with vasculitis and the subsequent risk of PCP warranting co-trimoxazole prophylaxis, we believe that the risk of hypoglycaemia should be highlighted.

Cotrimoxazole-induced hypoglycaemia in a patient with churg-strauss syndrome

Cotrimoxazole is a commonly used antimicrobial agent which is traditionally indicated in the management of pneumocystis infection of which HIV and immunosuppressed individuals are at high risk. Furthermore, it can be used on the long term for prophylactic indications. Hypoglycaemia following commencement of cotrimaoxazole is a rare adverse effect which was first described in 1988. We describe a case of hypoglycaemia shortly following initiation of cotrimoxazole indicated as long-term prophylaxis on a background of Churg-Strauss syndrome. The patient was symptomatic for hypoglycaemia despite simultaneous use of high-dose prednisolone; however, the hypoglycaemia did not require a hospital admission. We will explore the risk factors, monitoring requirements, and the mechanism by which co-trimoxazole induces hypoglycaemia.