Magnesium Sulfate Flashcards Preview

AZ DHS DRUG PROFILES > Magnesium Sulfate > Flashcards

Flashcards in Magnesium Sulfate Deck (21)
Loading flashcards...
1
Q

Generic Name:

A

Magnesium Sulfate

2
Q

Supplied:

A

1g/2mL vial

3
Q

Class:

A

Electrolyte, tocolytic

4
Q

Mechanism of Action: Pharmacology:

A

Second most plentiful intracellular cation; essential to enhance intracellular potassium replenishment and activity of many enzymes; important role in neurochemical transmission and muscular excitability (may decrease acetylcholine released by nerve impulses); decreases myocardial irritability and neuromuscular irritability.

5
Q

Mechanism of Action: Clinical:

A

Cardiac-reduces ventricular irritability, especially when associated with hypomagnesemia; inhibition of muscular excitability.

6
Q

Indications and Field Use:

A
- Torsade de pointes, drug of choice
- Hypomagnesemia
- Pre-term labor (PTL)
- Pregnancy-induced hypertension (PIH, toxemia of pregnancy, pre-eclampsia and/or eclampsia).
- Hyperreactive Airway - Severe Asthma
7
Q

Contraindications:

A

- Hypermagnesemia
- Use cautiously in patients with impaired renal function and pre-existing heart blocks (relative).
- Precautions: Caution when used with barbituates, narcotics, or other hypnotics (or system anesthetics) in conjunction with Magnesium Sulfate due to the additive central depressive effects of magnesium.

8
Q

Adverse Reactions:

A

CV: Hypotension (may be transient), flushing, circulatory collapse, depressed cardiac function, heart block, asystole, smooth muscle relaxant (antihypertensive effects).

Resp: Respiratory depression and/or paralysis. This adverse reaction may occur in both mother and/or infant during or up to 24 hours after the administration of Magnesium Sulfate.

CNS: Sweating, drowsiness, hypothermia, depressed reflexes progressing to flaccidity and paralysis. This adverse reaction may occur in both mother and/or infant during the administration of or up to 24 hours after the administration of Magnesium Sulfate.

GI: Nausea

GU: Mild diuretic

Meta: Hypocalcemia, hypermagnesemia

9
Q

Incompatibilities/Drug Interactions:

A

Concurrent digitalization increases danger of dysrhythmias

10
Q

Adult Dosage: Torsades de Pointes:

A

1 - 2g IV diluted in 50 - 100 mL NS or D5W administered over 1 to 2 minutes, followed by the same amount infused over 1 hour.

11
Q

Adult Dosage: Hypomagnesemia:

A

Dilute 1 - 2g in 50 - 100 mL NS or D5W administered IV push over 5 to 60 minutes.

12
Q

Adult Dosage: Respiratory/Severe Asthma:

A
Initial Infusion (field) 2g Magnesium Sulfate mixed in
50 mL NS or D5W to be infused IV using microdrip tubing over 5 to 10 minutes. Stop infusion if hypotension, respiratory depression or bradycardia develop.
13
Q

Adult Dosage: Pre-term labor (PTL):

A
  • Initial bolus (Field and Interfacility): 4 - 6g over 15 to 20 minutes (Suggested method is the addition of 4g to 100 mL D5W, LR or NS. Resultant concentration is 40 mg/mL.)
  • Maintenance Infusion (Interfacility only): 1-4g/hour infusion rate. (Suggested method for treatment of premature labor is to follow initial bolus with infusion of 2g/hr which may be continued until uterine contractions are reduced to < 1 every 10 minutes. Then, infusion is decreased to 1g/hr and continued for 24 to 72 hrs. One method for mixing infusion is the addition of 40g to 1000 mL LR. Resultant concentration equals 40 mg/ml. If this concentration is run at 50 mL/hr, Magnesium Sulfate delivered equals 2g/hr).
14
Q

Adult Dosage: Pregnancy induced hypertension, pre-eclampsia/eclampsia, (PIH):

A
  • Initial bolus (Field and Interfacility): 3 - 6g over 10 to 15 minutes (Suggested method is the addition of 4g to 100 mL D5W, LR or NS. Resultant concentration is 40 mg/mL).
  • Maintenance Infusion (Interfacility only): Follow bolus with 1 - 3g/hour infusion rate. (Same mixture as for PTL). Rebolus: In an eclamptic emergency may rebolus with Magnesium Sulfate, 2 - 4g depending on patient size (mixed as an initial bolus) over 10-15 minutes if respirations >12/minute and urine output >30 ml/hr.
15
Q

Routes of Administration:

A
  • IV infusion

- IO

16
Q

Onset of Action:

A
  • Seconds

- 20 minutes for IV infusion (respiratory)

17
Q

Peak Effects:

A

Not known

18
Q

Duration of Action:

A

24 hours or greater

19
Q

Arizona Drug Box Minimum Supply:

A

5g

20
Q

Special Notes:

A

- O2 should be administered to patients receiving Magnesium Sulfate.

- For specific emergencies:
o OB emergencies maintenance infusions of Magnesium Sulfate should be administered by infusion pump to prevent toxicity. Therefore, loading bolus therapy only, using a minimum of microdrip tubing is recommended for field to hospital intervention for OB indications.

o Interfacility transfers may include a loading dose followed by a maintenance infusion of Magnesium Sulfate which requires an infusion pump.

o Respiratory (Asthma) emergencies: Magnesium Sulfate follows Albuterol & Atrovent SVN and administration of 0.3 IM Epi (1:1000).

21
Q

Special Notes Continued:

A

- For IV/IO infusions (respiratory) start and stop times should be closely monitored and documented per administration guidelines of 20 minutes or greater.
- Transport gravid patients lying or tilted to left side to prevent restricting venous return to heart.
- Use cautiously in patients with impaired renal function, pre-existing heart blocks and women in labor.
- Evaluate cardiac status and ECG assessing for prolonged PR and widened QRS intervals.
- Do not delay intubation or ventilation for Magnesium Sulfate administration in patients suffering severe asthma episode.
- Keep Calcium Chloride (10%) 10 ml available to reverse magnesium toxicity. See: Calcium Chloride profile. Use extreme caution if the patient is on digoxin.
- Monitor vital signs every 15 minutes in patients receiving Magnesium Sulfate infusion. If respirations less than 12/min, discontinue Magnesium Sulfate infusion, notify medical direction.
- Hourly intake and output should be monitored on long transport; urine output should be greater than 30 mL/hr.
- When given to toxemic mothers within 24 hours before delivery observe newborn for signs/symptoms of Magnesium Sulfate toxicity (neuromuscular and/or respiratory depression).
- Interfacility maternal transport teams are recommended and available for the transport of patients requiring continuous IV infusions of Magnesium Sulfate.
- In treatment of seizures associated with PIH it may be necessary to use an
anticonvulsant such as diazepam.
- Eclampsia may occur up to six weeks after delivery