Octreotide reverses hyperinsulinemia and prevents hypoglycemia induced by sulfonylurea overdoses

A review on the pharmacokinetic properties and toxicity considerations for chloroquine and hydroxychloroquine to potentially treat coronavirus patients

The SARS-CoV-2 virus, caused a novel emerged coronavirus disease, is growing rapidly worldwide. Few studies have evaluated the efficacy and safety of Chloroquine (CQ), an old antimalarial drug, and Hydroxychloroquine (HCQ) in the treatment of COVID-19 infection. HCQ is derived from CQ by adding a hydroxyl group into it and is a less toxic derivative of CQ for the treatment of COVID-19 infection because it is more soluble. This article summarizes pharmacokinetic properties and toxicity considerations for CQ and HCQ, drug interactions, and their potential efficacy against COVID-19. The authors also look at the biochemistry changes and clinical uses of CQ and HCQ, and supportive treatments following toxicity occurs. It was believed that CQ and HCQ may provide few benefits to COVID-19 patients. A number of factors should be considered to keep the drug safe, such as dose, in vivo animal toxicological findings, and gathering of metabolites in plasma and/or tissues. The main conclusion of this review is that CQ and HCQ with considered to their ADMET properties has major shortcomings and fully irresponsible.

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.

Treatment of sulfonylurea and insulin overdose

The most common toxicity associated with sulfonylureas and insulin is hypoglycaemia. The article reviews existing evidence to better guide hypoglycaemia management. Sulfonylureas and insulin have narrow therapeutic indices. Small doses can cause hypoglycaemia, which may be delayed and persistent. All children and adults with intentional overdoses need to be referred for medical assessment and treatment. Unintentional supratherapeutic ingestions can be initially managed at home but if symptomatic or if there is persistent hypoglycaemia require medical referral. Patients often require intensive care and prolonged observation periods. Blood glucose concentrations should be assessed frequently. Asymptomatic children with unintentional sulfonylurea ingestions should be observed for 12 h, except if this would lead to discharge at night when they should be kept until the morning. Prophylactic intravenous dextrose is not recommended. The goal of therapy is to restore and maintain euglycaemia for the duration of the drug's toxic effect. Enteral feeding is recommended in patients who are alert and able to tolerate oral intake. Once insulin or sulfonylurea-induced hypoglycaemia has developed, it should be initially treated with an intravenous dextrose bolus. Following this the mainstay of therapy for insulin-induced hypoglycaemia is intravenous dextrose infusion to maintain the blood glucose concentration between 5.5 and 11 mmol l(-1) . After sulfonylurea-induced hypoglycaemia is initially corrected with intravenous dextrose, the main treatment is octreotide which is administered to prevent insulin secretion and maintain euglycaemia. The observation period varies depending on drug, product formulation and dose. A general guideline is to observe for 12 h after discontinuation of intravenous dextrose and, if applicable, octreotide.

Paradoxical and bidirectional drug effects

A paradoxical drug reaction constitutes an outcome that is opposite from the outcome that would be expected from the drug's known actions. There are three types: 1. A paradoxical response in a condition for which the drug is being explicitly prescribed. 2. Paradoxical precipitation of a condition for which the drug is indicated, when the drug is being used for an alternative indication. 3. Effects that are paradoxical in relation to an aspect of the pharmacology of the drug but unrelated to the usual indication. In bidirectional drug reactions, a drug may produce opposite effects, either in the same or different individuals, the effects usually being different from the expected beneficial effect. Paradoxical and bidirectional drug effects can sometimes be harnessed for benefit; some may be adverse. Such reactions arise in a wide variety of drug classes. Some are common; others are reported in single case reports. Paradoxical effects are often adverse, since they are opposite the direction of the expected effect. They may complicate the assessment of adverse drug reactions, pharmacovigilance, and clinical management. Bidirectional effects may be clinically useful or adverse. From a clinical toxicological perspective, altered pharmacokinetics or pharmacodynamics in overdose may exacerbate paradoxical and bidirectional effects. Certain antidotes have paradoxical attributes, complicating management. Apparent clinical paradoxical or bidirectional effects and reactions ensue when conflicts arise at different levels in self-regulating biological systems, as complexity increases from subcellular components, such as receptors, to cells, tissues, organs, and the whole individual. These may be incompletely understood. Mechanisms of such effects include different actions at the same receptor, owing to changes with time and downstream effects; stereochemical effects; multiple receptor targets with or without associated temporal effects; antibody-mediated reactions; three-dimensional architectural constraints; pharmacokinetic competing compartment effects; disruption and non-linear effects in oscillating systems, systemic overcompensation, and other higher-level feedback mechanisms and feedback response loops at multiple levels. Here we review and provide a compendium of multiple class effects and individual reactions, relevant mechanisms, and specific clinical toxicological considerations of antibiotics, immune modulators, antineoplastic drugs, and cardiovascular, CNS, dermal, endocrine, musculoskeletal, gastrointestinal, haematological, respiratory, and psychotropic agents.

Hypoglycemia revisited in the acute care setting

Hypoglycemia is a common finding in both daily clinical practice and acute care settings. The causes of severe hypoglycemia (SH) are multi-factorial and the major etiologies are iatrogenic, infectious diseases with sepsis and tumor or autoimmune diseases. With the advent of aggressive lowering of HbA1c values to achieve optimal glycemic control, patients are at increased risk of hypoglycemic episodes. Iatrogenic hypoglycemia can cause recurrent morbidity, sometime irreversible neurologic complications and even death, and further preclude maintenance of euglycemia over a lifetime of diabetes. Recent studies have shown that hypoglycemia is associated with adverse outcomes in many acute illnesses. In addition, hypoglycemia is associated with increased mortality among elderly and non-diabetic hospitalized patients. Clinicians should have high clinical suspicion of subtle symptoms of hypoglycemia and provide prompt treatment. Clinicians should know that hypoglycemia is associated with considerable adverse outcomes in many acute critical illnesses. In order to reduce hypoglycemia-associated morbidity and mortality, timely health education programs and close monitoring should be applied to those diabetic patients presenting to the Emergency Department with SH. ED disposition strategies should be further validated and justified to achieve balance between the benefits of euglycemia and the risks of SH. We discuss relevant issues regarding hypoglycemia in emergency and critical care settings.

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.

Use of octreotide acetate to prevent rebound hypoglycaemia in sulfonylurea overdose

A short cut review was carried out to establish whether octreotide can prevent rebound hypoglycaemia after sulfonylurea overdose. Fourteen papers were found using the reported searches, of which two presented the best evidence to answer the clinical question. The author, date and country of publication, patient group studied, study type, relevant outcomes, results and study weaknesses of these best papers are summarised in table 2. It is concluded that octreotide may be safe and effective in this situation.

Toxicology case of the month: oral hypoglycaemic overdose

A teenager ingests 375 mg of glipizide and 14.5 g of melformin intentionally in a small country town. She presents to the local medical facility with symptoms and signs of hypoglycaemia. Using a risk assessment based approach, the management of suiphonylurea and metformin overdose is discussed. Sulphonylurea overdose invariably results in profound hypoglycaemia that requires resuscitation with IV dextrose and the use of octreotide as an antidote. Metfonnin overdose rarely causes problems.

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.

Management of antidiabetic medications in overdose

The drugs used to treat diabetes mellitus are diverse and involve several classes. However, these drugs can be roughly separated into hypoglycaemic agents, such as insulin and the sulphonylureas, and antihyperglycaemic agents, such as the biguanides, the alpha-glucosidase inhibitors and troglitazone. Reports of insulin overdose are rare. The major effects of insulin overdose are secondary to the insult to the CNS produced by hypoglycaemia. The mainstay of insulin overdose management is glucose replacement therapy. Sulphonylureas are the most commonly used oral antihyperglycaemic agents in the management of type 2 (non-insulin-dependent; NIDDM) diabetes mellitus. Sulphonylureas primarily cause serum glucose reduction by stimulating the release of preformed insulin from the pancreatic islets. The mainstay of sulphonylurea overdose management is glucose replacement therapy, and in severe cases, reduction of insulin release. In the large majority of patients intravenous glucose supplementation will be sufficient to maintain euglycaemia. Repaglinide, a meglitinide analogue, is a new nonsulphonylurea oral hypoglycaemic agent. In overdose, this drug may produce prolonged hypoglycaemia similar to the sulphonylureas. The primary problem with biguanide overdose is the potential for lactic acidosis. The management of biguanide overdose is largely supportive and directed at correcting the metabolic acidosis along with associated complications. The alpha-glucosidase inhibitors, acarbose, voglibose and miglitol competitively and reversibly inhibit the alpha-glucosidase enzymes (glucoamylase, sucrase, maltase and isomaltase) in the brush border in the small intestine, which delays the hydrolysis of complex carbohydrates. They appear unlikely to produce hypoglycaemia in overdose, but abdominal discomfort and diarrhoea may occur. Troglitazone is the first thiazolidinedione antidiabetic drug available. There are no data on overdose, probably because of its very recent introduction. Overdoses with antidiabetic drugs produce major morbidity, with many cases requiring intensive care medicine and prolonged hospital stays. However, fatalities are rare when treatment is initiated early. The management of the hypoglycaemic drugs (insulin and sulphonylureas) is based primarily on restoring and maintaining euglycaemia via intravenous dextrose supplementation. In the case of the sulphonylureas, reduction of insulin secretion via pharmacological intervention may also be necessary. With biguanides the main risk appears to be cardiovascular collapse secondary to profound acidosis. The management focus is on restoring acid-base balance with hyperventilation and the use of insulin to shift the utilisation of glucose from the nonoxidative pathway to the oxidative pathway. Use of haemodialysis has shown equivocal results but may be valuable in metformin overdose.

Comparative tolerability profiles of oral antidiabetic agents

The sulphonylureas and the biguanides are widely used as adjuncts to dietary measures in the treatment of non-insulin-dependent (type 2) diabetes mellitus (NIDDM). Adverse effect profiles differ markedly between the sulphonylureas and biguanides, reflecting differences in chemical structure and mode of action. Sulphonylureas are generally well tolerated, although pharmacokinetic differences between these agents have important clinical implications. The main adverse effect associated with sulphonylureas is hypoglycaemia. This effect is a predictable consequence of the principal pharmacological effect of these drugs, i.e. sensitisation of the islet beta-cell to glucose, resulting in enhanced endogenous insulin secretion. Sulphonylurea-induced suppression of hepatic glucose production may cause profound and protracted hypoglycaemia, especially in elderly patients, in individuals with intercurrent illnesses and reduced caloric intake, or when taken in combination with other compounds with hypoglycaemic potential, e.g. alcohol (ethanol). Sulphonylureas with a longer duration of action, notably chlorpropamide and glibenclamide (glyburide), are more liable to induce serious hypoglycaemia, particularly when drug elimination is reduced by renal impairment. Other drugs such as salicylates may potentiate the actions of sulphonylureas, thereby increasing the risk of hypoglycaemia. Biguanide therapy is associated with alterations in lactate homeostasis which under certain clinical circumstances may result in fatal lactic acidosis. Phenformin is associated with a markedly greater risk of lactic acidosis than metformin. Phenformin has been withdrawn in many countries for this reason. All biguanides must be avoided in patients with renal impairment, hepatic dysfunction and cardiac failure--conditions where drug accumulation or disordered lactate metabolism may predispose to lactic acidosis. Phenformin should not be given to individuals who exhibit a severe, genetically conferred hepatic defect of hydroxylation which impedes metabolism of this drug. Less seriously, the biguanides are associated with a relatively high incidence of gastrointestinal adverse effects which limit compliance. Acarbose, a competitive inhibitor of intestinal alpha-glucosidases, has recently been introduced. In contrast to the sulphonylureas and biguanides, acarbose has not been associated with life-threatening adverse effects. This reflects the low systemic absorption of the drug and, predictably, its principal unwanted effects are gastrointestinal disturbances resulting from iatrogenic carbohydrate malabsorption.