Lecture Classes for BNS 1st Year Maharajgunj Nursing Campus

1. Uterine Relaxants (Tocolytics)
For BNS Ist Year
Dr. Pravin Prasad
Ist Year Resident, MD Clinical Pharmacology
Maharajgunj Medical Campus
2nd October, 2015(Asoj 15, 2072); Friday

2. Drugs used as Tocolytics
• Adrenergic agonist: Ritoridine
• Calcium channel blockers: Nifedipine
• Oxytocin Antagonist: Atosiban
• Magnesium sulfate
• Miscellaneous: Ethyl alcohol, nitrates, progesterone, general
anaesthetics, indomethacin, Halothane

3. Ritoridine
• Mechanism of action:
– β2 selective agonist
• Use:
— Supress premature labour
— Delay delivery
— Treatment beyond 48 hrs not
recommended
• Side Effects:
‒ CVS – hypotension, tachycardia,
arrhythmia, pulmonary edema
‒ Metabolic – hyperglycaemia,
hyperinsulinemia, hypokalemia
‒ Anexity, restlessness, headache
‒ Neonate – foetal pulmonary
edema, hypoglycaemia, ileus
• Contraindication:
– Mother having diabetes or heart
disease, or receiving β blockers or
steroids

4. Nifedipine
• Mechanism of Action:
• Reduces the tone of myometrium and opposes contraction
• Prominent smooth muscle relaxant action
• Side Effects:
• Maternal - Tachycardia, Hypotension
• Foetal – Foetal Hypoxia due to placental perfusion

5. Other Tocolytics
• Atosiban
• Mechanism of Action: Antagonist at the oxytocin receptors
• Availability in Nepal (??)
• Magnesium sulfate
• Mechanism of Action: Acts as tocolytics by competiting with Ca++ ions for
entry into myocardium through both voltage gated and ligand gated Ca++
channels
• Higher risk to be used as tocolytics – increases perinatal mortality
• Not recommended
• Halothane
• Used as relaxant when external or internal version is attempted

6. Thank You!!