MAGNESIUM SULFATE IN DEXTROSE- magnesium sulfate heptahydrate injection, solution
Hospira, Inc.
Flexible Plastic Container
For Intravenous Use Only
Rx only
DESCRIPTION
Magnesium Sulfate in 5% Dextrose Injection, USP is a sterile, nonpyrogenic solution of magnesium sulfate heptahydrate and dextrose in water for injection. Each 100 mL contains 1 or 2 g magnesium sulfate heptahydrate and dextrose, hydrous 5 g in water for injection. May contain sulfuric acid and/or sodium hydroxide for pH adjustment. The pH is 4.5 (3.5 to 6.5). It is available in 1% and 2% concentrations. See HOW SUPPLIED section for the content and characteristics of available dosage forms and sizes.
Magnesium Sulfate, USP heptahydrate is chemically designated MgSO4 � 7H2 O, colorless crystals or white powder freely soluble in water.
Dextrose, USP is chemically designated D-glucose, monohydrate (C6 H12 O6 � H2 O), a hexose sugar freely soluble in water. It has the following structural formula:
structural formula Dextrose, USP
Molecular weight 198.17.
Water for Injection, USP is chemically designated H2 O.
The flexible plastic container is fabricated from a specially formulated polyvinylchloride. Water can permeate from inside the container into the overwrap but not in amounts sufficient to affect the solution significantly. Solutions in contact with the plastic container may leach out certain chemical components from the plastic in very small amounts; however, biological testing was supportive of the safety of the plastic container materials. Exposure to temperatures above 25�C/77�F during transport and storage will lead to minor losses in moisture content. Higher temperatures lead to greater losses. It is unlikely that these minor losses will lead to clinically significant changes within the expiration period.
CLINICAL PHARMACOLOGY
Magnesium (Mg++) is an important cofactor for enzymatic reactions and plays an important role in neurochemical transmission and muscular excitability.
Magnesium prevents or controls convulsions by blocking neuromuscular transmission and decreasing the amount of acetylcholine liberated at the end plate by the motor nerve impulse. Magnesium is said to have a depressant effect on the central nervous system, but it does not adversely affect the mother, fetus or neonate when used as directed in eclampsia or pre-eclampsia. Normal serum magnesium levels range from 1.3 to 2.1 mEq/liter.
As serum magnesium rises above 4 mEq/liter, the deep tendon reflexes are first decreased and then disappear as the serum level approaches 10 mEq/liter. At this level respiratory paralysis may occur. Heart block also may occur at this or lower serum levels of magnesium.
Magnesium acts peripherally to produce vasodilation. With low doses only flushing and sweating occur, but larger doses cause lowering of blood pressure. The central and peripheral effects of magnesium poisoning are antagonized to some extent by intravenous administration of calcium.
With intravenous administration the onset of anticonvulsant action is immediate and lasts about 30 minutes. Following intramuscular administration the onset of action occurs in about one hour and persists for three to four hours. Effective anticonvulsant serum levels range from 2.5 to 7.5 mEq/liter.
Pharmacokinetics:
Absorption: Intravenously administered magnesium is immediately absorbed.
Distribution: Approximately 1-2% of total body magnesium is located in the extracellular fluid space. Magnesium is 30% bound to albumin.
Metabolism: Magnesium is not metabolized.
Excretion: Magnesium is excreted solely by the kidney at a rate proportional to the serum concentration and glomerular filtration.
Special Populations:
Renal Insufficiency: Magnesium is excreted solely by the kidney. In patients with severe renal insufficiency, the dose should be lower and frequent serum magnesium levels must be obtained (see DOSAGE AND ADMINISTRATION).
Hepatic Insufficiency: Magnesium is excreted solely by the kidney. No dosing adjustments are necessary in hepatic insufficiency.
Drug-Drug Interactions: Drug induced renal losses of magnesium occur with the following drugs or drug classes:
Aminoglycosides Amphotericin B
Cyclosporine Diuretics
Digitalis Cisplatin
Alcohol
INDICATIONS AND USAGE
Magnesium Sulfate in 5% Dextrose Injection, USP is indicated for the prevention and control of seizures in preeclampsia and eclampsia, respectively. When used judiciously it effectively prevents and controls the convulsions of eclampsia without producing deleterious depression of the central nervous system of the mother or infant. However, other effective drugs are available for this purpose.
