MAGNESIUM SULFATE- magnesium sulfate injection, answer
Hospira, Inc.
Magnesium Sulfate Injection, USP 50% is a sterile, nonpyrogenic, concentrated answer of magnesium sulfate heptahydrate in Water for Injection, USP administered by the intravenous (IV) or intramuscular (IM) routes as an electrolyte replenisher or anticonvulsant. Should be diluted earlier than IV use.
Every mL accommodates: Magnesium sulfate heptahydrate 500 mg; Water for Injection q.s. Sulfuric acid and/or sodium hydroxide might have been added for pH adjustment. The pH of a 5% answer is 6.0 (5.5 to 7.0). The 50% focus has an osmolarity of 4.06 mOsmol/mL (calc.); 2.03 mM/mL magnesium sulfate anhydrous and 4.06 mEq/mL magnesium sulfate anhydrous.
The answer accommodates no bacteriostat, antimicrobial agent or added buffer (apart from pH adjustment) and is meant just for use as a single dose injection. When smaller doses are required the unused portion must be discarded with your entire unit.
Magnesium sulfate heptahydrate is chemically designated MgSO4 • 7H2O with a molecular weight of 246.47 and happens as colorless crystals or white powder freely soluble in water.
Magnesium is a crucial cofactor for enzymatic reactions and performs an vital position in neurochemical transmission and muscular excitability.
As a dietary adjunct in hyperalimentation, the exact mechanism of motion for magnesium is unsure. Early signs of hypomagnesemia (lower than 1.5 mEq/L) might develop as early as three to 4 days or inside weeks.
Predominant deficiency results are neurological, e.g., muscle irritability, clonic twitching and tremors. Hypocalcemia and hypokalemia usually comply with low serum ranges of magnesium. Whereas there are massive shops of magnesium current intracellularly and within the bones of adults, these shops usually usually are not mobilized sufficiently to keep up plasma ranges. Parenteral magnesium remedy repairs the plasma deficit and causes deficiency signs and indicators to stop.
Magnesium prevents or controls convulsions by blocking neuromuscular transmission and reducing the quantity of acetylcholine liberated on the end-plate by the motor nerve impulse. Magnesium is alleged to have a depressant impact on the central nervous system (CNS), but it surely doesn’t adversely have an effect on the lady, fetus or neonate when used as directed in eclampsia or pre-eclampsia. Regular plasma magnesium ranges vary from 1.5 to 2.5 mEq/L.
As plasma magnesium rises above 4 mEq/L, the deep tendon reflexes are first decreased after which disappear because the plasma degree approaches 10 mEq/L. At this degree respiratory paralysis might happen. Coronary heart block additionally might happen at this or decrease plasma ranges of magnesium. Serum magnesium concentrations in extra of 12 mEq/L could also be deadly.
Magnesium acts peripherally to supply vasodilation. With low doses solely flushing and sweating happen, however bigger doses trigger reducing of blood stress. The central and peripheral results of magnesium poisoning are antagonized to some extent by IV administration of calcium.
Pharmacokinetics
With IV administration the onset of anticonvulsant motion is quick and lasts about 30 minutes. Following IM administration the onset of motion happens in about one hour and persists for 3 to 4 hours. Efficient anticonvulsant serum ranges vary from 2.5 to 7.5 mEq/L. Magnesium is excreted solely by the kidneys at a price proportional to the plasma focus and glomerular filtration.
Normal
Administer with warning if flushing and sweating happens. When barbiturates, narcotics or different hypnotics (or systemic anesthetics) are to be given at the side of magnesium, their dosage must be adjusted with warning due to additive CNS depressant results of magnesium.
As a result of magnesium is faraway from the physique solely by the kidneys, the drug must be used with warning in sufferers with renal impairment. Urine output must be maintained at a degree of 100 mL or extra throughout the 4 hours previous every dose. Monitoring serum magnesium ranges and the affected person’s medical standing is important to keep away from the implications of overdosage in toxemia. Scientific indications of a protected dosage routine embrace the presence of the patellar reflex (knee jerk) and absence of respiratory despair (roughly 16 breaths or extra/minute). When repeated doses of the drug are given parenterally, knee jerk reflexes must be examined earlier than every dose and if they’re absent, no extra magnesium must be given till they return. Serum magnesium ranges normally enough to regulate convulsions vary from 3 to six mg/100 mL (2.5 to five mEq/L). The energy of the deep tendon reflexes begins to decrease when magnesium ranges exceed 4 mEq/L. Reflexes could also be absent at 10 mEq magnesium/L, the place respiratory paralysis is a possible hazard. An injectable calcium salt must be instantly out there to counteract the potential hazards of magnesium intoxication in eclampsia.
Magnesium sulfate injection (50%) should be diluted to a focus of 20% or much less previous to IV infusion. Charge of administration must be sluggish and cautious, to keep away from producing hypermagnesemia. The 50% answer additionally must be diluted to twenty% or much less for IM injection in infants and kids.
Laboratory Exams
Magnesium sulfate injection shouldn’t be given until hypomagnesemia has been confirmed and the serum focus of magnesium is monitored. The traditional serum degree is 1.5 to 2.5 mEq/L.
Drug Interactions
CNS Depressants — When barbiturates, narcotics or different hypnotics (or systemic anesthetics), or different CNS depressants are to be given at the side of magnesium, their dosage must be adjusted with warning due to additive CNS depressant results of magnesium. CNS despair and peripheral transmission defects produced by magnesium could also be antagonized by calcium.
Neuromuscular Blocking Brokers — Extreme neuromuscular block has occurred in sufferers receiving parenteral magnesium sulfate and a neuromuscular blocking agent; these medication must be administered concomitantly with warning.
Cardiac Glycosides — Magnesium sulfate must be administered with excessive warning in digitalized sufferers, as a result of severe adjustments in cardiac conduction which may end up in coronary heart block might happen if administration of calcium is required to deal with magnesium toxicity.
Being pregnant – “magnesium vial”
Teratogenic Results
(See WARNINGS and PRECAUTIONS)
Magnesium sulfate may cause fetal abnormalities when administered past 5-7 days to pregnant girls. There are retrospective epidemiological research and case stories documenting fetal abnormalities resembling hypocalcemia, skeletal demineralization, osteopenia and different skeletal abnormalities with steady maternal administration of magnesium sulfate for greater than 5 to 7 days.1-10 Magnesium sulfate injection must be used throughout being pregnant provided that clearly wanted. If this drug is used throughout being pregnant, the lady must be apprised of the potential hurt to the fetus.
Nonteratogenic Results
When administered by steady IV infusion (particularly for greater than 24 hours previous supply) to regulate convulsions in a toxemic girl, the new child might present indicators of magnesium toxicity, together with neuromuscular or respiratory despair. (See OVERDOSAGE).