Sulfonylureas or sulphonylureas are a class of organic compounds used in medicine and agriculture. The functional group consists of a sulfonyl group (-S(=O)2) with its sulphur atom bonded to a nitrogen atom of a ureylene group (N,N-dehydrourea, a dehydrogenated derivative of urea). The side chains R1 and R2 distinguish various sulfonylureas. Sulfonylureas are the most widely used herbicide.
Many sulfonylureas are also used as herbicides, because they can interfere with plant biosynthesis of certain amino acids. [1]
As herbicides sulfonylureas function by interfering with biosynthesis of the amino acids valine, isoleucine, and leucine, specifically via acetolactate synthase inhibition. Compounds in this class include amidosulfuron, azimsulfuron, bensulfuron-methyl, chlorimuron-ethyl, chlorsulfuron, ethametsulfuron-methyl, cinosulfuron, ethoxysulfuron, flazasulfuron, flupyrsulfuron-methyl-sodium, imazosulfuron, metsulfuron-methyl, nicosulfuron, [2] oxasulfuron, primisulfuron-methyl, prosulfuron, pyrazosulfuron-ethyl, rimsulfuron, sulfometuron-methyl, sulfosulfuron, thifensulfuron-methyl, triasulfuron, tribenuron-methyl, and triflusulfuron-methyl. [3] These are broad-spectrum herbicides that kill plants weeds or pests by inhibiting the enzyme acetolactate synthase. In the 1960s, more than 1 kg/ha (0.89 lb/acre) crop protection chemical was typically applied, while sulfonylureates allow as little as 1% as much material to achieve the same effect. [4]
They are widely used as antidiabetic drugs in the management of diabetes mellitus type 2. They act by increasing secretion of insulin from the beta cells in the pancreas. [5]
Sulfonylureas are ineffective where there is absolute deficiency of insulin production such as in type 1 diabetes or post-pancreatectomy.[ citation needed ]
Sulfonylureas can be used to treat some types of neonatal diabetes. Historically, people with hyperglycemia and low blood insulin levels were diagnosed with type 1 diabetes by default, but it has been found that patients who receive this diagnosis before 6 months of age are often candidates for receiving sulfonylureas rather than insulin throughout life. [6]
A 2011 Cochrane systematic review evaluated the effects on treatment of Latent Autoimmune Diabetes in Adults (LADA) and found that Sulfonylureas did not improve metabolic control of glucose at 3 and 12 months, even worsening HbA1c levels in some cases, when compared to insulin. [7] The same review did not find improvement of fasting C-peptide following treatment with sulfonylurea. [7] Still, it is important to highlight that the studies available to be included in this review presented considerable flaws in quality and design. [7]
While prior sulfonylureas were associated with worse outcomes, newer agents do not appear to increase the risk of death, heart attacks, or strokes. [8] This is further reinforced by a 2020 Cochrane systematic review which did not find enough evidence of reduction of all-cause mortality, serious adverse events, cardiovascular mortality, non-fatal myocardial infarction, non-fatal stroke or end-stage renal disease when comparing metformin monotherapy to sulfonylureas. [9] This same review also did not find improvement in health-related quality of life. [9]
In individuals with impaired-glucose tolerance, a 2019 systematic review only found one suitable trial comparing the effects of Sulphonylurea with Metformin in reduction or delay of risk of developing type 2 diabetes, however this trial did not report patient-relevant outcomes. [10] Another systematic review completed in the same year suggested that there is limited evidence if the combined used of Metformin with Sulphonylurea compared to the combination of Metformin plus another glucose-lowering intervention, provides benefit or harm in mortality, severe adverse events, macrovascular and microvascular complications. [11] Combined Metformin and Sulphonylurea therapy did appear to lead to higher risk of Hypoglycemia. [11]
Sulfonylureas are also used experimentally to inhibit release of interleukin 1 beta from the NALP3 (or NLRP3) inflammasome. [12]
Sulfonylureas – as opposed to metformin, the thiazolidinediones, pramlintide and other newer treatments – may induce hypoglycemia as a result of excesses in insulin production and release. Hypoglycemia appears to happen more often with sulfonylureas than compared to other treatments. [13] This typically occurs if the dose is too high, and the patient is fasting. Some people attempt to change eating habits to prevent this, however it can be counterproductive.
Like insulin, sulfonylureas can induce weight gain, mainly as a result of their effect to increase insulin levels and thus use of glucose and other metabolic fuels. Other side-effects are: gastrointestinal upset, headache and hypersensitivity reactions.
The safety of sulfonylurea therapy in pregnancy is unestablished. Prolonged hypoglycemia (4 to 10 days) has been reported in children borne to mothers taking sulfonylureas at the time of delivery. [14] Impairment of liver or kidney function increase the risk of hypoglycemia, and are contraindications. Since other antidiabetic drugs cannot be used either under these circumstances, insulin therapy is typically recommended during pregnancy and in liver and kidney failure, although some of the newer agents offer potentially better options.
A 2011 Cochrane review found evidence that treatment of LADA using sulfonylureas lead to earlier insulin dependence in approximately 30% of cases. [7]
A 2014 Cochrane review found tentative evidence that people treated with sulfonylureas have fewer non-fatal cardiovascular events than those treated with metformin (RR 0.7) but a higher risk of severe hypoglycemia (RR 5.6). There was not enough data available to determine the risk of mortality or of cardiovascular mortality. [15] An earlier review by the same group found a statistically significant increase in the risk of cardiovascular death for first generation sulfonylureas relative to placebo (RR 2.6) but there was not enough data to determine the relative risk of first generation sulfonylureas relative to insulin (RR 1.4). Likewise it was not possible to determine the relative mortality risk of second generation sulfonylureas relative to metformin (RR 1.0), insulin (RR 1.0), or placebo. [16] The FDA requires sulfonylureas to carry a label warning regarding increased risk of cardiovascular death. [14]
A 2020 Cochrane systematic review comparing metformin monotherapy to sulfonylureas did not find enough evidence of reduction of all-cause mortality, serious adverse events, cardiovascular mortality, non-fatal myocardial infarction, non-fatal stroke or end-stage renal disease. [9]
Second-generation sulfonylureas have increased potency by weight, compared to first-generation sulfonylureas. Similarly, ACCORD (Action to Control Cardiovascular Risk in Diabetes) [17] and the VADT (Veterans Affairs Diabetes Trial) [18] studies showed no reduction in heart attack or death in patients assigned to tight glucose control with various drugs.
Drugs that potentiate or prolong the effects of sulfonylureas and therefore increase the risk of hypoglycemia include acetylsalicylic acid and derivatives, allopurinol, sulfonamides, and fibrates. Drugs that worsen glucose tolerance, contravening the effects of antidiabetics, include corticosteroids, isoniazid, oral contraceptives and other estrogens, sympathomimetics, and thyroid hormones. Sulfonylureas tend to interact with a wide variety of other drugs, but these interactions, as well as their clinical significance, vary from substance to substance. [19] [20]
Sulfonylureas contain a central S-arylsulfonylurea structure with a p-substituent on the phenyl ring (R1) and various groups terminating the urea N′ end group (R2). Chemically, this functionality can be easily installed by reacting aryl sulfonamides (R1—C6H4—SO2NH2) with isocyanates (R2—NCO).
Sulfonylureas are divided into 3 classes on basis of therapeutic efficiency of their antidiabetic action:
They include acetohexamide, carbutamide, chlorpropamide, glycyclamide (tolcyclamide), metahexamide, tolazamide and tolbutamide.
They include glibenclamide (glyburide), glibornuride, gliclazide, [21] glipizide, gliquidone, glisoxepide and glyclopyramide.
They include glimepiride, although it is sometimes considered a second-generation drug. [22] [23]
Sulfonylureas bind to and close ATP-sensitive K+ (KATP) channels on the cell membrane of pancreatic beta cells, which depolarizes the cell by preventing potassium from exiting. This depolarization opens voltage-gated Ca 2+ channels. The rise in intracellular calcium leads to increased fusion of insulin granules with the cell membrane, and therefore increased secretion of mature insulin. [24]
There is some evidence that sulfonylureas also sensitize β-cells to glucose, that they limit glucose production in the liver, that they decrease lipolysis (breakdown and release of fatty acids by adipose tissue) and decrease clearance of insulin by the liver.[ citation needed ]
The KATP channel is an octameric complex of the inward-rectifier potassium ion channel Kir6.x and sulfonylurea receptor SUR which associate with a stoichiometry of 4:4. [24]
Furthermore, it has been shown that sulfonylureas interact with the nucleotide exchange factor Epac2. [25] [26] Mice lacking this factor exhibited a decreased glucose-lowering effect upon sulfonylurea treatment.
Sulfonylureas were discovered in 1942, by the chemist Marcel Janbon and co-workers in France, [27] who were studying sulfonamide antibiotics and discovered that the compound sulfonylurea induced hypoglycemia in animals. [28]
Research and development (translational research and commercial application development) for sulfonylureas as pharmaceuticals (as diagnostic and therapeutic agents in prediabetes and diabetes) happened in the 1950s and 1960s, as explored at Tolbutamide § History .
Research and development (translational research and commercial application development) for sulfonylureas as herbicides happened in the 1970s and 1980s, as explored for example in a volume of the Sloan Technology Series focusing on the sociotechnological aspects of agriculture (Canine 1995); [29] the DuPont Experimental Station led this development. [29]
Intensive insulin therapy or flexible insulin therapy is a therapeutic regimen for diabetes mellitus treatment. This newer approach contrasts with conventional insulin therapy. Rather than minimize the number of insulin injections per day, the intensive approach favors flexible meal times with variable carbohydrate as well as flexible physical activities. The trade-off is the increase from 2 or 3 injections per day to 4 or more injections per day, which was considered "intensive" relative to the older approach. In North America in 2004, many endocrinologists prefer the term "flexible insulin therapy" (FIT) to "intensive therapy" and use it to refer to any method of replacing insulin that attempts to mimic the pattern of small continuous basal insulin secretion of a working pancreas combined with larger insulin secretions at mealtimes. The semantic distinction reflects changing treatment.
Type 2 diabetes (T2D), formerly known as adult-onset diabetes, is a form of diabetes mellitus that is characterized by high blood sugar, insulin resistance, and relative lack of insulin. Common symptoms include increased thirst, frequent urination, fatigue and unexplained weight loss. Symptoms may also include increased hunger, having a sensation of pins and needles, and sores (wounds) that do not heal. Often symptoms come on slowly. Long-term complications from high blood sugar include heart disease, strokes, diabetic retinopathy which can result in blindness, kidney failure, and poor blood flow in the limbs which may lead to amputations. The sudden onset of hyperosmolar hyperglycemic state may occur; however, ketoacidosis is uncommon.
Metformin, sold under the brand name Glucophage, among others, is the main first-line medication for the treatment of type 2 diabetes, particularly in people who are overweight. It is also used in the treatment of polycystic ovary syndrome. It is sometimes used as an off-label adjunct to lessen the risk of metabolic syndrome in people who take antipsychotics. Metformin is not associated with weight gain and is taken by mouth.
Drugs used in diabetes treat diabetes mellitus by decreasing glucose levels in the blood. With the exception of insulin, most GLP-1 receptor agonists, and pramlintide, all diabetes medications are administered orally and are thus called oral hypoglycemic agents or oral antihyperglycemic agents. There are different classes of hypoglycemic drugs, and selection of the appropriate agent depends on the nature of diabetes, age, and situation of the person, as well as other patient factors.
The thiazolidinediones, abbreviated as TZD, also known as glitazones after the prototypical drug ciglitazone, are a class of heterocyclic compounds consisting of a five-membered C3NS ring. The term usually refers to a family of drugs used in the treatment of diabetes mellitus type 2 that were introduced in the late 1990s.
Rosiglitazone is an antidiabetic drug in the thiazolidinedione class. It works as an insulin sensitizer, by binding to the PPAR in fat cells and making the cells more responsive to insulin. It is marketed by the pharmaceutical company GlaxoSmithKline (GSK) as a stand-alone drug or for use in combination with metformin or with glimepiride. First released in 1999, annual sales peaked at approximately $2.5-billion in 2006; however, following a meta-analysis in 2007 that linked the drug's use to an increased risk of heart attack, sales plummeted to just $9.5-million in 2012. The drug's patent expired in 2012.
Pioglitazone, sold under the brand name Actos among others, is an anti-diabetic medication used to treat type 2 diabetes. It may be used with metformin, a sulfonylurea, or insulin. Use is recommended together with exercise and diet. It is not recommended in type 1 diabetes. It is taken by mouth.
Gestational diabetes is a condition in which a person without diabetes develops high blood sugar levels during pregnancy. Gestational diabetes generally results in few symptoms; however, it increases the risk of pre-eclampsia, depression, and of needing a Caesarean section. Babies born to individuals with poorly treated gestational diabetes are at increased risk of macrosomia, of having hypoglycemia after birth, and of jaundice. If untreated, diabetes can also result in stillbirth. Long term, children are at higher risk of being overweight and of developing type 2 diabetes.
Acarbose (INN) is an anti-diabetic drug used to treat diabetes mellitus type 2 and, in some countries, prediabetes. It is a generic sold in Europe and China as Glucobay, in North America as Precose, and in Canada as Prandase.
Glibenclamide, also known as glyburide, is an antidiabetic medication used to treat type 2 diabetes. It is recommended that it be taken together with diet and exercise. It may be used with other antidiabetic medication. It is not recommended for use by itself in type 1 diabetes. It is taken by mouth.
Exenatide, sold under the brand name Byetta among others, is a medication used to treat type 2 diabetes. It is used together with diet, exercise, and potentially other antidiabetic medication. It is a treatment option after metformin and sulfonylureas. It is given by injection under the skin.
Meglitinides or glinides are a class of drugs used to treat type 2 diabetes.
Inhibitors of dipeptidyl peptidase 4 are a class of oral hypoglycemics that block the enzyme dipeptidyl peptidase-4 (DPP-4). They can be used to treat diabetes mellitus type 2.
Sitagliptin, sold under the brand name Januvia among others, is an anti-diabetic medication used to treat type 2 diabetes. In the United Kingdom it is listed as less preferred than metformin or a sulfonylurea. It is taken by mouth. It is also available in the fixed-dose combination medication sitagliptin/metformin.
Alpha-glucosidase inhibitors (AGIs) are oral anti-diabetic drugs used for diabetes mellitus type 2 that work by preventing the digestion of carbohydrates. Carbohydrates are normally converted into simple sugars (monosaccharides) by alpha-glucosidase enzymes present on cells lining the intestine, enabling monosaccharides to be absorbed through the intestine. Hence, alpha-glucosidase inhibitors reduce the impact of dietary carbohydrates on blood sugar.
Saxagliptin, sold under the brand name Onglyza, is an oral hypoglycemic of the dipeptidyl peptidase-4 (DPP-4) inhibitor class. Early development was solely by Bristol-Myers Squibb; in 2007 AstraZeneca joined with Bristol-Myers Squibb to co-develop the final compound and collaborate on the marketing of the drug.
Voglibose is an alpha-glucosidase inhibitor used for lowering postprandial blood glucose levels in people with diabetes mellitus. Voglibose is a research product of Takeda Pharmaceutical Company, Japan's largest pharmaceutical company. Vogilbose was discovered in 1981, and was first launched in Japan in 1994, under the trade name BASEN, to improve postprandial hyperglycemia in diabetes mellitus.
Dulaglutide, sold under the brand name Trulicity among others, is a medication used for the treatment of type 2 diabetes in combination with diet and exercise. It is also approved in the United States for the reduction of major adverse cardiovascular events in adults with type 2 diabetes who have established cardiovascular disease or multiple cardiovascular risk factors. It is a once-weekly injection.
SGLT2 inhibitors, also called gliflozins or flozins, are a class of medications that inhibit sodium-glucose transport proteins in the nephron, unlike SGLT1 inhibitors that perform a similar function in the intestinal mucosa. The foremost metabolic effect of this is to inhibit reabsorption of glucose in the kidney and therefore lower blood sugar. They act by inhibiting sodium-glucose transport protein 2 (SGLT2). SGLT2 inhibitors are used in the treatment of type 2 diabetes. Apart from blood sugar control, gliflozins have been shown to provide significant cardiovascular benefit in people with type 2 diabetes. As of 2014, several medications of this class had been approved or were under development. In studies on canagliflozin, a member of this class, the medication was found to enhance blood sugar control as well as reduce body weight and systolic and diastolic blood pressure.
Dapagliflozin/Saxagliptin is a combination medication designed to help manage diabetes mellitus, a chronic condition that affects how the body handles glucose (sugar). This medication combines two active ingredients, dapagliflozin/Saxagliptin, to address different aspects of diabetes control. Dapagliflozin/Saxagliptin sold under the brand name Qtern. It is a combination of dapagliflozin and saxagliptin. It is taken by mouth.