Which one is the main action of prostaglandins?

UPPSC-2021

Pharmacology

Easy

Appeared in: UPPSC-2021

Explanation

Prostaglandins, specifically Prostaglandin E₂ (PGE₂) and Prostaglandin F₂α (PGF₂α), are potent stimulators of the myometrium (uterine muscle).
They increase the tone, frequency, and strength of uterine contractions throughout pregnancy, an effect known as an oxytocic action.
This powerful contractile effect is harnessed clinically for inducing labor, terminating pregnancy (medical abortion), and controlling postpartum hemorrhage.
In addition to contraction, prostaglandins also promote cervical ripening by softening and dilating the cervix, which is crucial for the initiation of labor.

Option B: This is the opposite of the primary effect of PGE₂ and PGF₂α on the uterus. These prostaglandins cause uterine contraction, not relaxation.
Option C: While prostaglandins play a physiological role in the inflammatory process that leads to follicular rupture during ovulation, this is not considered their main pharmacological action compared to their potent and widely used effects on the uterus.
Option D: Prostaglandins do not increase the production of sperm (spermatogenesis).

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pharmacological actions of prostaglandins as background academic context rather than a clinical decision trigger.
Nurses administering prostaglandins (e.g., Dinoprostone gel/insert, Misoprostol tablets) for labor induction must continuously monitor uterine activity for hyperstimulation or tachysystole (more than 5 contractions in 10 minutes) and assess the fetal heart rate for signs of distress, as excessive contractions can reduce blood flow to the placenta.
Understanding this primary action is critical for anticipating and managing potential adverse effects, such as uterine rupture (a rare but serious complication), fever, and gastrointestinal distress (nausea, vomiting, diarrhea).
What if? If a patient receiving a prostaglandin infusion for labor induction develops uterine tachysystole with evidence of fetal distress (e.g., late decelerations), the nurse's priority actions are to stop the prostaglandin, place the patient in a left lateral position to improve uteroplacental perfusion, administer supplemental oxygen, and immediately notify the healthcare provider. A tocolytic agent like terbutaline may be ordered to relax the uterus.

How to Approach the Question

This is a factual recall question from pharmacology.
First, identify the keyword in the question stem: 'prostaglandins' and the qualifier 'main action'.
Recall the major physiological and pharmacological roles of prostaglandins. They are lipid autacoids with diverse functions, including roles in inflammation, pain, fever, blood flow, and smooth muscle contraction.
Consider the context of nursing and medicine, where the most prominent and clinically utilized actions are often emphasized. In obstetrics, the effect of prostaglandins on the uterus is paramount.
Evaluate each option: 'Acceleration of uterine contraction' is a well-known, potent effect used for labor induction, abortion, and PPH management, making it a strong candidate for the 'main action'.
Eliminate the other options by recalling that uterine relaxation is the opposite effect, the role in ovulation is less significant pharmacologically, and the effect on spermatogenesis is incorrect.

Concept Tested & Keywords

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E6 Pharmacology KD Tripathi Essentials 9e Part 1 p. 224-226