P8 Flashcards
Glizazide
Class = Sulphonylurea
An oral hypoglycemic agent which is rapidly absorbed and completely metabolized.
MoA: Sulfonylureas likely bind to ATP-sensitive potassium-channel receptors on the pancreatic cell surface, reducing potassium conductance and causing depolarization of the membrane. Depolarization stimulates calcium ion influx through voltage-sensitive calcium channels, raising intracellular concentrations of calcium ions, which induces the secretion, or exocytosis, of insulin.
Repaglinide
It belongs to the meglitinide class of short-acting insulin secretagogues, which act by binding to β cells of the pancreas to stimulate insulin release.
Use: Oral antihyperglycemic agent. Used to treat non-insulin dependent diabetes mellitus,
Glucagon
MoA: Endogenous substance normally released from pancreatic alpha cells when INSULIN levels are low.
The main effect is as an agonist at glucagon receptors (GR) in the liver. Activation of these receptors sets up a second messenger cascade involving cAMP – PKA – PPK and finally activation of glycogen phosphorylase. This promotes the metabolism of glycogen into glucose which is then released into the bloodstream.
Insulin
The body’s main, endogenous hypoglycemic agent.
Released from pancreatic alpha cells in response to elevated blood sugar.
MoA: Acts via the insulin receptor (IR) to control a vast range of processes in almost all metabolically active cells in the body. The second messenger pathways activated are extremely numerous and complex.
Effects: The main effects are the absorption of glucose into metabolising tissues and the subsequent promotion of glycolysis (converting glucose into useable energy (ATP) and storing of glucose for future use as glycogen (glycogenesis).
Metformin
Biguanide antihyperglycemic agent
MoA: Differ from other classes of oral antihyperglycemic agents. Metformin decreases blood glucose levels by decreasing hepatic glucose production, decreasing intestinal absorption of glucose, and improving insulin sensitivity by increasing peripheral glucose uptake and utilisation
Use: Used for treating non-insulin-dependent diabetes mellitus (NIDDM). It improves glycemic control by decreasing hepatic glucose production, decreasing glucose absorption and increasing insulin-mediated glucose uptake.
Octreotide
Octreotide is the acetate salt of a cyclic octapeptide. It is a long-acting octapeptide with pharmacologic properties mimicking those of the natural hormone somatostatin.
Use: Octreotide exerts pharmacologic actions similar to the natural hormone, somatostatin. It is an even more potent inhibitor of growth hormone, glucagon, and insulin than somatostatin
MoA: Octreotide binds to somatostatin receptors. These receptors are coupled via pertussis toxin sensitive G proteins which lead to inhibition of adenylyl cyclase.
Pancreatin
Pancrelipase is an enzyme mixture isolated from porcine or bovine pancreas, sometimes called pancreatin. It contains 3 enzymes: amylase, lipase, and a protease (chymotrypsin).
Pioglitazone
Thiazolidinedione
MoA: An agonist at peroxisome proliferator-activated receptor gamma nuclear receptor (PPAR-γ).
Reduces insulin resistance in metabolically active tissues (i.e. increases glucose absorption, storage and conversion into ATP) and prevents glucose release from the liver
Acarbose
An alpha-glucosidase inhibitor
MoA: Alpha glucosidase is present in the gut and is essential for breaking down complex carbohydrates (i.e. starch) into glucose. Thus less glucose is released into the hepatic portal vein following a meal
Exenatide
Glucagon-like peptide-1 receptor (GLP1R) agonists.
Exenatide is a functional analog of the human incretin.
MoA: Incretins enhance glucose-dependent insulin secretion and exhibit other antihyperglycemic actions following their release into the circulation from the gut.
Liraglutide
Glucagon-like peptide-1 receptor (GLP1R) agonists
Victoza contains liraglutide, an analog of human GLP-1 and acts as a GLP-1 receptor agonist
Sitagliptin
Sitagliptin is a new oral hypoglycemic (anti-diabetic drug) of the new dipeptidyl peptidase-4 (DPP-4) inhibitor class of drugs.
MoA: This enzyme-inhibiting drug is to be used either alone or in combination with metformin or a thiazolidinedione for control of type 2 diabetes mellitus.
The drug works to competitively inhibit a protein/enzyme, dipeptidyl peptidase 4 (DPP-4), that results in an increased amount of active incretins (GLP-1 and GIP), reduced amount of release of glucagon (diminishes its release) and increased release of insulin.
Use: Hypoglycemic (anti-diabetic drug)
Ipragliflozin
Ipragliflozin is under investigation in Type 2 Diabetes and Diabetes Mellitus, Type 2.
MoA: Sodium-glucose transport protein 2 (SGLT2) antagonist
Cabergoline + Bromocriptine
Dopamine receptor agonist
MoA: Some effect on serotonin receptors. Dopamine released from hypothalamus acts on D2 receptors in pituitary to decrease endocrine secretion.
All areas of pituitary affected: Anterior pituitary (Thyroid stimulating hormone (TSH), growth hormone (GH), Adrenocorticotropic hormone (ACTH), prolactin, lutenising hormone (LH), follicle stimulating hormone (FSH)); Intermediate pituitary (Melanocyte stimulating hormone (MSH)); Posterior pituitary (antidiuretic hormone (ADH) also called vasopressin, oxytocin).
Metoclopramide
Dopamine antagonist
MoA: Dopamine D2R antagonist. Some effect on serotonin receptors, particularly 5HT3R.
Inhibits the effect of hypothalamic dopamine release on the pituitary gland thus increasing endocrine secretion
Carbimazole
An imidazole antithyroid agent.
A pro-drug taken orally and metabolised in the liver to the active metabolite methimazole.
MoA: Metabolized to Methimazole by liver. Methimazole inhibits thyroid peroxidase, thus reducing iodination of the hormone precursor thyroglobulin and reducing levels of thyroid hormones triiodothyronine (T3) and thyroxine (T4).
Levothyroxine
A synthetic hormone
The major hormone derived from the thyroid gland.
Use: Full agonist at thyroxine (T4) receptors. Thus mimics the effects of thyroxine release at the thyroid hormone receptor increasing cardiac output, ventilation rate, basal metabolic rate, bone growth, neuronal maturation and endometrial thickening.
Protirelin
Protirelin is the pharmaceutically available synthetic analogue of the endogenous peptide thyrotropin-releasing hormone (TRH).
It is a tri-peptide tropic hormone, released by the hypothalamus, that stimulates the release of Thyroid Stimulating Hormone (TSH) and prolactin from the anterior pituitary.
Use: Mimics the effect of TRH released from hypothalamus on TRHR in anterior pituitary, thus increasing the amount of TSH release and therefore promoting release of thyroid hormones.