Magnesium sulfate

dr.joan

Magnesium sulfate :
Trade names: Magnesium sulfate

Class: Anticonvulsant, electrolyte, saline laxative

Pregnancy: (Category

Action:
It is an important cation present in the extracelular fluid.
It is an essential electrolyte for muscle contraction, certain enzyme system & never transmissions.
Magnesium depresses CNS & control convulsion by blocking the release of acetylcholine at the myoneural junction.
Uses:
Seizures associated with toxemia of pregnancy.
Epilepsy
laxative
Hypomagnesaemia
In total parenteral nutrition

Dose:

Hypomagnesaemia :neonate IV 25-50mg/kg every 8-12 hours for 2-3 days, Children IM,IV 25-50 mg/kg/dose every 4-6 hours for 3-4 days, maintenance 30-60mg/kg/day, Adult IM,IV 1 g every 6 hours for 4 doses
Maintenance electrolyte requirement 25-50 mg/kg/day
Prevention of seizure recurrence in eclampsia, initially 4 g by intravenous injection over 5–15 minutes, , followed by intravenous infusion, 1 g/hour for at least 24 hours after last seizure
Contraindications:
· In the presence of heart block.
· In the presence of myocardial damage.


Side effects:
· Magnesium intoxication depression , flushing, hypotension , respiratory paralysis, muscle paralysis, respiratory failure .

N.B.
· Suppression of knee-Jerk reflex can be used to determine toxicity
· Respiratory failure may result if drug is given after disappearance of this reflex.
Treatment of Magnesium intoxication:
· Use artificial ventilation immediately.
· Have calcium glutinate readily available for I.V. use.

Nursing considerations:
· For I.V. administer. only 1.5 ml of 10% solution\minute.
· For I.M., inject the drug deep into the muscle using 50% solution.
· As a laxative, dissolve in a glass of ice water or other fluid to lessen disagreeable taste.
· Obtain baseline Mg level.
· Obtain history of kidney disease.
· Check with the physician before administering magnesium if any of the following conditions exist:
Absent patellar or knee jerk reflex.
R.R. less than 16\m
Urinary out put less than 100 ml\4 hrs .
Patient has a history of heart block or myocardial damage.
· Have available I.V. Calcium gluconate .
· Don’t administer drug 2 hrs preceding delivery of the baby.
· If mother has received I.V. therapy of this drug 24 hours prior to delivery, assess the newborn for neurologic & respiratory depression.