Effectiveness of octreotide in a case of refractory sulfonylurea-induced hypoglycemia

Current insights into the microbial degradation of nicosulfuron: Strains, metabolic pathways, and molecular mechanisms

Nicosulfuron is among the sulfonylurea herbicides that are widely used to control annual and perennial grass weeds in cornfields. However, nicosulfuron residues in the environment are likely to cause long-lasting harmful environmental and biological effects. Nicosulfuron degrades via photo-degradation, chemical hydrolysis, and microbial degradation. The latter is crucial for pesticide degradation and has become an essential strategy to remove nicosulfuron residues from the environment. Most previous studies have focused on the screening, degradation characteristics, and degradation pathways of biodegrader microorganisms. The isolated nicosulfuron-degrading strains include Bacillus, Pseudomonas, Klebsiella, Alcaligenes, Rhodopseudomonas, Ochrobactrum, Micrococcus, Serratia, Penicillium, Aspergillus, among others, all of which have good degradation efficiency. Two main intermediates, 2-amino-4,6-dimethoxypyrimidine (ADMP) and 2-aminosulfonyl-N,N-dimethylnicotinamide (ASDM), are produced during microbial degradation and are derived from the C-N, C-S, and S-N bond breaks on the sulfonylurea bridge, covering almost every bacterial degradation pathway. In addition, enzymes related to the degradation of nicosulfuron have been identified successively, including the manganese ABC transporter (hydrolase), Flavin-containing monooxygenase (oxidase), and E3 (esterase). Further in-depth studies based on molecular biology and genetics are needed to elaborate on their role in the evolution of novel catabolic pathways and the microbial degradation of nicosulfuron. To date, few reviews have focused on the microbial degradation and degradation mechanisms of nicosulfuron. This review summarizes recent advances in nicosulfuron degradation and comprehensively discusses the potential of nicosulfuron-degrading microorganisms for bioremediating contaminated environments, providing a reference for further research development on nicosulfuron biodegradation in the future.

Somatostatin analogues for the treatment of hyperinsulinaemic hypoglycaemia

Hyperinsulinaemic hypoglycaemia (HH) is a biochemical finding of low blood glucose levels due to the dysregulation of insulin secretion from pancreatic β-cells. Under normal physiological conditions, glucose metabolism is coupled to β-cell insulin secretion so that blood glucose levels are maintained within the physiological range of 3.5-5.5 mmol/L. However, in HH this coupling of glucose metabolism to insulin secretion is perturbed so that insulin secretion becomes unregulated. HH typically occurs in the neonatal, infancy and childhood periods and can be due to many different causes. Adults can also present with HH but the causes in adults tend to be different. Somatostatin (SST) is a peptide hormone that is released by the delta cells (δ-cells) in the pancreas. It binds to G protein-coupled SST receptors to regulate a variety of location-specific and selective functions such as hormone inhibition, neurotransmission and cell proliferation. SST plays a potent role in the regulation of both insulin and glucagon secretion in response to changes in glucose levels by negative feedback mechanism. The half-life of SST is only 1-3 min due to quick degradation by peptidases in plasma and tissues. Thus, a direct continuous intravenous or subcutaneous infusion is required to achieve the therapeutic effect. These limitations prompted the discovery of SST analogues such as octreotide and lanreotide, which have longer half-lives and therefore can be administered as injections. SST analogues are used to treat different forms of HH in children and adults and therapeutic effect is achieved by suppressing insulin secretion from pancreatic β-cells by complex mechanisms. These treatments are associated with several side effects, especially in the newborn period, with necrotizing enterocolitis being the most serious side effect and hence SS analogues should be used with extreme caution in this age group.

Octreotide for hypoglycemia caused by sulfonylurea and DPP-4 inhibitor

We describe a type 2 diabetes patient with persistent hypoglycemia caused by sulfonylurea misuse on top of a DPP-4 inhibitor. Hyperinsulinemia was exaggerated by dextrose administration, but was successfully treated with octreotide. Since many patients are currently treated with DPP-4 inhibitors, the importance of octreotide has been increasing. For refractory sulfonylurea-induced hypoglycemia, especially when the patient is also being given an incretin-based therapy, octreotide should be considered.

Antidotes for toxicological emergencies: a practical review

PURPOSE

Appropriate therapies for commonly encountered poisonings, medication overdoses, and other toxicological emergencies are reviewed, with discussion of pharmacists' role in ensuring their ready availability and proper use.

SUMMARY

Poisoning is the second leading cause of injury-related morbidity and mortality in the United States, with more than 2.4 million toxic exposures reported each year. Recently published national consensus guidelines recommend that hospitals providing emergency care routinely stock 24 antidotes for a wide range of toxicities, including toxic-alcohol poisoning, exposure to cyanide and other industrial agents, and intentional or unintentional overdoses of prescription medications (e.g., calcium-channel blockers, β-blockers, digoxin, isoniazid). Pharmacists can help reduce morbidity and mortality due to poisonings and overdoses by (1) recognizing the signs and symptoms of various types of toxic exposure, (2) guiding emergency room staff on the appropriate use of antidotes and supportive therapies, (3) helping to ensure appropriate monitoring of patients for antidote response and adverse effects, and (4) managing the procurement and stocking of antidotes to ensure their timely availability.

CONCLUSION

Pharmacists can play a key role in reducing poisoning and overdose injuries and deaths by assisting in the early recognition of toxic exposures and guiding emergency personnel on the proper storage, selection, and use of antidotal therapies.

Octreotide's role in the management of sulfonylurea-induced hypoglycemia

The objective is to evaluate the evidence regarding octreotide's efficacy as a treatment for sulfonylurea-induced hypoglycemia. A search of PubMed for articles published from 1965 to 2008 using combinations of the terms octreotide, antidote, sulfonylurea, overdose, poisoning, and toxicity was performed. References from identified articles were reviewed for additional sources. Animal studies, case reports, case series, and randomized controlled trials were evaluated. An animal model of sulfonylurea overdose demonstrates that octreotide reduces the number of refractory sulfonylurea-induced hypoglycemic episodes. Published case reports describe the use of octreotide to prevent recurrent hypoglycemia after sulfonylurea overdose. A retrospective case series demonstrates that administration of octreotide decreases the need for supplemental dextrose boluses as well as hypoglycemic events. Two prospective, controlled trials determined that octreotide and supplemental dextrose increase blood glucose concentrations with fewer hypoglycemic events. Based on animal and human data, there is sufficient evidence to recommend the use of octreotide with supplemental dextrose for the treatment of sulfonylurea-induced hypoglycemia.

Drugs and pharmaceuticals: management of intoxication and antidotes

The treatment of patients poisoned with drugs and pharmaceuticals can be quite challenging. Diverse exposure circumstances, varied clinical presentations, unique patient-specific factors, and inconsistent diagnostic and therapeutic infrastructure support, coupled with relatively few definitive antidotes, may complicate evaluation and management. The historical approach to poisoned patients (patient arousal, toxin elimination, and toxin identification) has given way to rigorous attention to the fundamental aspects of basic life support--airway management, oxygenation and ventilation, circulatory competence, thermoregulation, and substrate availability. Selected patients may benefit from methods to alter toxin pharmacokinetics to minimize systemic, target organ, or tissue compartment exposure (either by decreasing absorption or increasing elimination). These may include syrup of ipecac, orogastric lavage, activated single- or multi-dose charcoal, whole bowel irrigation, endoscopy and surgery, urinary alkalinization, saline diuresis, or extracorporeal methods (hemodialysis, charcoal hemoperfusion, continuous venovenous hemofiltration, and exchange transfusion). Pharmaceutical adjuncts and antidotes may be useful in toxicant-induced hyperthermias. In the context of analgesic, anti-inflammatory, anticholinergic, anticonvulsant, antihyperglycemic, antimicrobial, antineoplastic, cardiovascular, opioid, or sedative-hypnotic agents overdose, N-acetylcysteine, physostigmine, L-carnitine, dextrose, octreotide, pyridoxine, dexrazoxane, leucovorin, glucarpidase, atropine, calcium, digoxin-specific antibody fragments, glucagon, high-dose insulin euglycemia therapy, lipid emulsion, magnesium, sodium bicarbonate, naloxone, and flumazenil are specifically reviewed. In summary, patients generally benefit from aggressive support of vital functions, careful history and physical examination, specific laboratory analyses, a thoughtful consideration of the risks and benefits of decontamination and enhanced elimination, and the use of specific antidotes where warranted. Data supporting antidotes effectiveness vary considerably. Clinicians are encouraged to utilize consultation with regional poison centers or those with toxicology training to assist with diagnosis, management, and administration of antidotes, particularly in unfamiliar cases.

Comparison of Octreotide and Standard Therapy Versus Standard Therapy Alone for the Treatment of Sulfonylurea-Induced Hypoglycemia

STUDY OBJECTIVE

This study is designed to test the hypothesis that the administration of octreotide acetate (Sandostatin; Novartis Pharmaceuticals) in addition to standard therapy will increase serum glucose level measured at serial intervals in patients presenting to the emergency department (ED) with sulfonylurea-induced hypoglycemia compared with standard therapy alone.

METHODS

This study was a prospective, double-blind, placebo-controlled trial. All adult patients who presented to the ED with hypoglycemia (serum glucose level < or = 60 mg/dL) and were found to be taking a sulfonylurea or a combination of insulin and sulfonylurea were screened for participation in the study. Study participants were randomized to receive standard treatment (1 ampule of 50% dextrose intravenously and carbohydrates orally) and placebo (1 mL of 0.9% normal saline solution subcutaneously) or standard treatment plus 1 dose of octreotide 75 microg subcutaneously. Subsequent treatment interventions were at the discretion of the inpatient internal medicine service.

RESULTS

A total of 40 patients (18 placebo; 22 octreotide) were enrolled. The mean serum glucose measurement at presentation was placebo 35 mg/dL and octreotide 39 mg/dL. The mean glucose values for octreotide patients compared with placebo were consistently higher during the first 8 hours but showed no difference in subsequent hours. Mean glucose differences approached statistical significance from 1 to 3 hours and were significant from 4 to 8 hours after octreotide or placebo administration.

CONCLUSION

The addition of octreotide to standard therapy in hypoglycemic patients receiving treatment with a sulfonylurea increased serum glucose values for the first 8 hours after administration in our patients. Recurrent hypoglycemic episodes occurred less frequently in patients who received octreotide compared with those who received placebo.

Octreotide Therapy for Recurrent Refractory Hypoglycemia Due to Sulfonylurea In Diabetes-Related Kidney Failure

OBJECTIVE

To describe a patient with kidney insufficiency from diabetes treated with glyburide, who presented with prolonged and recurrent hypoglycemia unresponsive to large intravenous doses of glucose, which was treated successfully with intravenously administered octreotide, and to review the therapeutic options for hypoglycemia.

METHODS

We present a case report of a 66-year-old man with diabetes causing chronic kidney disease, who was treated with orally administered glyburide, 7.5 mg twice a day. He initially presented to another hospital because of hypoglycemia and was treated with intravenously administered glucose and discharged. The next day, his family brought him to our emergency department because of recurring low blood glucose levels and symptoms of sweating, fever, and nightmares. Laboratory tests revealed a blood glucose level of 33 mg/dL and a creatinine concentration of 6.2 mg/dL.

RESULTS

The patient was treated with a 5% dextrose and, subsequently, a 10% dextrose infusion without any sustained improvement. The blood glucose level remained low despite the additional administration of 3 ampules of 50% dextrose in water. The patient was given a bolus of octreotide (50 mug subcutaneously) 14 hours after his second presentation. He received another 50-mug dose of octreotide 6 hours later. After this bolus, the hypoglycemia resolved, and he no longer required intravenous administration of glucose to maintain euglycemia.

CONCLUSION

Patients with diabetes and kidney disease frequently have persistent and difficult-to-treat hypoglycemia, unresponsive to conventional therapy. Octreotide is an effective and safe treatment for patients with refractory hypoglycemia attributable to sulfonylureas.

Emergency Management of Oral Hypoglycemic Drug Toxicity

There are several classes of oral diabetes medications available in the United States, including sulfonylureas, meglitinides, biguanides, glitazones, and alpha-glucosidase inhibitors. These different classes have various mechanisms of action, giving each class a unique potential for toxicity that necessitates a distinct approach to evaluation, treatment, and disposition of each class of drug. The practicing emergency physician must have an understanding of these differences to safely care for patients exposed to these medications.

Successful treatment of sulfonylurea-induced prolonged hypoglycemia with use of octreotide

OBJECTIVE

To report the successful use of octreotide in the management of prolonged hypoglycemia attributable to therapeutic doses of sulfonylureas.

METHODS

We present a case series of 6 patients with sulfonylurea-induced hypoglycemia, along with pertinent serial laboratory data and review of the course of management.

RESULTS

Most of our 6 study patients had diabetes mellitus, which had been managed with sulfonylurea therapy. In the context of renal failure or heart failure (or both), severe, prolonged hypoglycemia developed. Intermittent intravenous administration of 50% dextrose did not result in a sustained and adequate response. Continuous intravenous administration of dextrose-containing solutions was contraindicated because of fluid overload as a result of congestive heart failure or renal failure. Administration of octreotide, 50 microg subcutaneously every 8 hours, resulted in a prompt and sustained resolution of the hypoglycemia. In 3 of the 6 study subjects, measurements of insulin and C-peptide levels both before and after treatment confirmed the efficacy of the octreotide therapy.

CONCLUSION

Our cases demonstrate that octreotide proves to be an effective treatment intervention for prolonged hypoglycemia caused by therapeutic doses of sulfonylureas. This is the first major report of the safe and effective use of octreotide in the management of sulfonylurea-induced hypoglycemia outside the emergency department setting.

Bench-to-bedside review: Antidotal treatment of sulfonylurea-induced hypoglycaemia with octreotide

The major potential adverse effect of use of sulfonylurea agents (SUAs) is a hyperinsulinaemic state that causes hypoglycaemia. It may be observed during chronic therapeutic dosing, even with very low doses of a SUA, and especially in older patients. It may also result from accidental or intentional poisoning in both diabetic and nondiabetic patients. The traditional approach to SUA-induced hypoglycaemia includes administration of glucose, and glucagon or diazoxide in those who remain hypoglycaemic despite repeated or continuous glucose supplementation. However, these antidotal approaches are associated with several shortcomings, including further exacerbation of insulin release by glucose and glucagon, leading only to a temporary beneficial effect and later relapse into hypoglycaemia, as well as the adverse effects of both glucagon and diazoxide. Octreotide inhibits the secretion of several neuropeptides, including insulin, and has successfully been used to control life-threatening hypoglycaemia caused by insulinoma or persistent hyperinsulinaemic hypoglycaemia of infancy. Therefore, this agent should in theory also be useful to decrease glucose requirements and the number of hypoglycaemic episodes in patients with SUA-induced hypoglycaemia. This has apparently been confirmed by experimental data, one retrospective study based on chart review, and several anecdotal case reports. There is thus a need for further prospective studies, which should be adequately powered, randomized and controlled, to confirm the probable beneficial effect of octreotide in this setting.