obgyn drugs

Question 1

magnesium sulfate

Answer 1

Class: mineral/electrolyte, anticonvulsant

MOA: plays important role in neurotransmission and muscular activity

Pharmacokinetics: Onset- Immediate, Duration- 30-60 min

Indications: anticonvulsant associated with severe eclampsia and preeclampsia

AR/SE: diarrhea, flushing, sweating, bradycardia, drowsiness, hypotension, hypothermia, itching, rash

Contraindications: known allergy, hypermagnesemia, hypocalcemia, heart block

Dosage: pre-eclampsia/eclampsia: 4-6 grams by infusion over 30 minutes. (often followed by 1-2g/hr infusion)

Question 2

oxytocin ; pitocin

Answer 2

Class: Uterine stimulant, hormone

MOA: stimulates uterine smooth muscle, producing contractions similar to those in spontaneous labor

Pharmacokinetics: Onset immediate IV Duration 1 hr

Indications: postpartum control of bleeding after delivery of the placenta

AR/SE: Coma, Seizures, hypotension, N/V, tachycardia

Contraindications: known allergy

Dosage: 10 Units by slow IV solution (mix in a 500 or 1000 mL bag)

Special Considerations: (P class X)

Question 3

terbutaline

Answer 3

Class: bronchodilator, adrenergic, tocolytic

MOA: selective for beta 2 adrenergic receptor sites, with less effect on beta 1. Stimulation of beta 2 receptors in the uterus causes uterine relaxation and can suppress labor.

Indications: can be used in the management of preterm labor (unlabeled use)

AR/SE: nervousness, restlessness, tremor, headache.

Contraindications: known allergy

Dosage: 0.25 mg SC initially, then 5 mcg/min IV infusion; increase by 5 mcg/min every 10 min until contractions stop or max dose of 80 mcg/min

Special Considerations: (P class X)

Question 4

diazepam ; valium

Answer 4

Classification: Benzodiazepine, anticonvulsant

MOA: depresses the CNS by potentiating GABA, an inhibitory neurotransmitter; produces skeletal muscle relaxation.

Pharmacokinetics: Onset: IV 1-5 minutes, duration IV 15-60 min

Indications: treat seizure activity including status epilepticus; can be used as skeletal muscle relaxant

AR/SE: dizziness, drowsiness, hypotension

Contraindications: known allergy; pts with severe pulmonary impairment, liver dysfunction, uncontrolled severe pain, angle-closure glaucoma, preexisting CNS depression

Dosage: 5-10 mg IV may repeat q 5-10 min up to 30 mg total

Special Considerations: (P class D) may cause respiratory arrest if given too quickly or in excess. Do not mix with other drugs, may cause precipitate.

Question 5

hydralazine ; apresoline

Answer 5

Class: vasodilator, antihypertensive

MOA: direct-acting peripheral arteriolar vasodilator

Pharmacokinetics: Onset 5-20 min IV, Duration 2-6 hrs IV

Indications: moderate to severe hypertension, pre-eclampsia

AR/SE: tachycardia, sodium retention, edema, orthostatic hypotension, N/V/D

Contraindications: known allergy, intolerance to tartazine

Dosage: 10 mg IV may repeat as needed

Special Considerations: (P class c)