Singapore Drugs Database

Indication

Glucose pharmaceutical formulations (oral tablets, injections) are indicated for caloric supply and carbohydrate supplementation in case of nutrient deprivation. It is also used for metabolic disorders such as hypoglycemia.[L787]

Mechanism of Action

Glucose supplies most of the energy to all tissues by generating energy molecules ATP and NADH during a series of metabolism reactions called glycolysis. Glycolysis can be divided into two main phases where the preparatory phase is initiated by the phosphorylation of glucose by hexokinase to form glucose 6-phosphate.[A19402] The addition of the high-energy phosphate group activates glucose for the subsequent breakdown in later steps of glycolysis and is the rate-limiting step. Products end up as substrates for following reactions, to ultimately convert C6 glucose molecule into two C3 sugar molecules. These products enter the energy-releasing phase where the total of 4ATP and 2NADH molecules are generated per one glucose molecule. The total aerobic metabolism of glucose can produce up to 36 ATP molecules. These energy-producing reactions of glucose are limited to D-glucose as L-glucose cannot be phosphorylated by hexokinase.[T35] Glucose can act as precursors to generate other biomolecules such as vitamin C. It plays a role as a signaling molecule to control glucose and energy homeostasis. Glucose can regulate gene transcription, enzyme activity, hormone secretion, and the activity of glucoregulatory neurons. The types, number, and kinetics of glucose transporters expressed depends on the tissues and fine-tunes glucose uptake, metabolism, and signal generation to preserve cellular and whole body metabolic integrity.[A19401]

Pharmacokinetics

Absorption

Polysaccharides can be broken down into smaller units by pancreatic and intestinal glycosidases or intestinal flora. Sodium-dependent glucose transporter SGLT1 and GLUT2 (SLC2A2) play predominant roles in intestinal transport of glucose into the circulation.[A19395] SGLT1 is located in the apical membrane of the intestinal wall while GLUT2 is located in the basolateral membrane, but it was proposed that GLUT2 can be recruited into the apical membrane after a high luminal glucose bolus allowing bulk absorption of glucose by facilitated diffusion.[A19400] Oral preparation of glucose reaches the peak concentration within 40 minutes and the intravenous infusions display 100% bioavailability.[A19406]

Distribution

The mean volume of distribution after intravenous infusion is 10.6L.[A19407]

Metabolism

Glucose can undergo aerobic oxidation in conjunction with the synthesis of energy molecules. Glycolysis is the initial stage of glucose metabolism where one glucose molecule is degraded into two molecules of pyruvate via substrate-level phosphorylation. These products are transported to the mitochondria where they are further oxidized into oxygen and carbon dioxide.[A19402]

Elimination

Clearance

The mean metabolic clearance rate of glucose (MCR) for the 10 subjects studied at the higher insulin level was 2.27 ± 0.37 ml/kg/min at euglycemia and fell to 1.51±0.21 ml/kg/ at hyperglycemia. The mean MCR for the six subjects studied at the lower insulin level was 1.91 ± 0.31 ml/kg/min at euglycemia.[A19408]

Toxicity

Oral LD50 value in rats is 25800mg/kg. The administration of glucose infusions can cause fluid and solute overloading resulting in dilution of the serum electrolyte concentrations, overhydration, congested states, or pulmonary edema. Hypersensitivity reactions may also occur including anaphylactic/anaphylactoid reactions from oral tablets and intravenous infusions.[L786]

Active Ingredient/Synonyms

aldehydo-D-glucose | Anhydrous dextrose | D-Glucose in linear form | D-glucose, anhydrous | D(+)-Glucose | Dextrose anhydrous | Dextrose, anhydrous | Glucose | Glucose anhydrous | Glucose, anhydrous | D-glucose |

Indication

Magnesium chloride is used in several medical and topical (skin related) applications. Magnesium chloride usp, anhydrous uses as electrolyte replenisher, pharmaceutic necessity for hemodialysis and peritoneal dialysis fluids.

Mechanism of Action

Mechanism of action of magnesium chloride studied in 10 adult volunteers. Results suggested magnesium ion in duodenum is relatively weak stimulus to pancreas and gall bladder. It is weak stimulant to cholecystokinin release and inhibits net jejunal water absorption. The oral administration of a single 800 mg dose of magnesium chloride in healthy volunteers resulted in a diminished rate of intraluminal lipid and protein digestion. The most pronounced effect of magnesium chloride, however, was a decreased gastric emptying rate of both test meals. After correction for gastric emptying, no differences were noted in intraluminal lipid or protein digestion. Therefore, the lower lipid levels noted after magnesium supplementation are unlikely to be the result of altered lipid assimilation. Magnesium chloride slows gastric emptying but does not influence lipid digestion.

Pharmacokinetics

Absorption

Oral: Inversely proportional to amount ingested; 40% to 60% under controlled dietary conditions; 15% to 36% at higher doses

Distribution

Bone (50% to 60%); extracellular fluid (1% to 2%)

Metabolism

Magnesium levels are efficiently regulated by the kidneys. Magnesium also undergoes efficient enterohepatic circulation

Elimination

Clearance

Maximum magnesium clearance is directly proportional to creatinine clearance.

Toxicity

Mouse LD50 775mg/kg (intraperitoneal) Mouse LD50 : 7600mg/kg (oral) Rat LD 50 : 8100mg/kg (oral) Rat LD50 176mg/kg (intravenous) Severe toxicity occurs most often after intravenous infusions. It can also occur after chronic excessive oral doses, often in patients with renal insufficiency. Early manifestations are lethargy, hyporeflexia, followed by weakness, paralysis, hypotension, ECG changes (prolonged PR and QRS intervals), CNS depression, seizures, and respiratory depression. In overdose, magnesium impairs neuromuscular transmission, manifested as weakness and hyporeflexia.

Active Ingredient/Synonyms

Anhydrous magnesium chloride | Magnesium chloride anhydrous | Magnesium chloride |

Indication

This intravenous solution is indicated for use in adults and pediatric patients as a source of electrolytes and water for hydration. Also, designed for use as a diluent and delivery system for intermittent intravenous administration of compatible drug additives.

Mechanism of Action

Sodium and chloride — major electrolytes of the fluid compartment outside of cells (i.e., extracellular) — work together to control extracellular volume and blood pressure. Disturbances in sodium concentrations in the extracellular fluid are associated with disorders of water balance.

Pharmacokinetics

Absorption

Absorption of sodium in the small intestine plays an important role in the absorption of chloride, amino acids, glucose, and water. Chloride, in the form of hydrochloric acid (HCl), is also an important component of gastric juice, which aids the digestion and absorption of many nutrients.

Distribution

The volume of distribution is 0.64 L/kg.

Metabolism

The salt that is taken in to gastro intestinal tract remains for the most part unabsorbed as the liquid contents pass through the stomach and small bowel. On reaching the colon this salt, together with the water is taken in to the blood. As excesses are absorbed the kidney is constantly excreting sodium chloride, so that the chloride level in the blood and tissues remains fairly constant.Further more, if the chloride intake ceases, the kidney ceases to excrete chlorides. Body maintains an equilibrium retaining the 300gm of salt dissolved in the blood and fluid elements of the tissue dissociated into sodium ions and chloride ions.

Elimination

Toxicity

The rare inadvertent intravascular administration or rapid intravascular absorption of hypertonic sodium chloride can cause a shift of tissue fluids into the vascular bed, resulting in hypervolemia, electrolyte disturbances, circulatory failure, pulmonary embolism, or augmented hypertension. ( toxnet)

Active Ingredient/Synonyms

Sodium Chloride | Sodium Chloride |