User:M. Tam, Future UCSF Pharm.D/sandbox

Plan for Uterotonic page

 * This page requires more citations and more background on the agents listed. It would be helpful to include more information as to why uterotonic agents are used to induce contractions and how they are also used to treat postpartum hemorrhage. It might also be helpful to add how oxytocin is important in uterine contraction. Each of the agent could be better grouped in to therapeutic classes or classes related to their structure/function, with descriptions about how each of those classes function to stimulate contractions. Additionally, it maybe help to include more guidelines or describe when which drugs are used and for what reason. Other things to considers could be more facts about the drugs (ie indications, MOA, brand, formulations, doses).
 * I don't expect these changes to affect the work of people currently editing the article. There doesn't seem to be much work actively occurring. The last edit (minor) was made in April 2020. This work could considerably add to the page.

Proposed Edits
Labor and delivery is a sequential process that results in the birth of a fetus and placenta. It is dependent on maternal and fetal chemical signals to stimulate muscles in the uterus to contract and relax. Of such signals include prostaglandins and oxytocin. Uterotonics can be utilized these chemical pathways in order to medically stimulate contractions in labor induction or to treat postpartum hemorrhage.

Oxytocin
Oxytocin is a peptide hormone produced in the hypothalamus that plays an important role in many physiological functions. These functions include, enhancing mood social relationships, promotion of maternal behaviors and stimulations of uterine contractions among others roles. Uterine muscle contractions are induced via a G-protein pathway stemming from an oxytocin receptor. When oxytocin binds to its associated receptors in the uterus, a cascade is initiated that results in increase in calcium and muscle contractions. Thus the release of oxytocin helps to facilitate stronger contractions during labor to aid in delivery of the fetus. Additionally, during pregnancy, the uterine muscles have an increased concentration of oxytocin receptors, leading to the increased response to oxytocin as well. Oxytocin's Role in Labor Induction

Oxytocin is the most commonly used agent for labor induction. It is given intravenously since it is easily degraded by the body if given orally. While a patient is on oxytocin, it is important to monitor the mother and the fetus, specifically the mother's uterine activity and the fetal heart rate. The more common side effects of oxytocin include tachysystole, hyponatremia, and hypotension. Tachysystole is an increased rate of uterine contractions. If this occurs, it can be managed by lowering the dosage of oxytocin. Hyponatremia is a decreased concentration of sodium in the body as a result of increased fluids. This occurs due to oxytocin's similar structure to vasopressin (antidiuretic hormone). Hypotension, or low blood pressure, is also a common side effect due to oxytocin's ability to relax smooth muscle of vessels. In comparison to women in spontaneous labor, women in induced labor on oxytocin experience a longer latent phase, however the duration of labor after reaching active labor (when the cervix has reaches 6cm), the duration of labor is considered equal.

Oxytocin's Role in Postpartum Hemorrhage

The most common cause of postpartum hemorrhage is a loss of muscle tone in the uterus. Normally, the uterus will contract to constrict blood vessels and decrease the flow of blood to prevent bleeding out. However, if there is a loss of muscle tone, see uterine atony, there is an increased risk of bleeding. Oxytocin is the first-line pharmacological step to help prevent PPH and treat PPH.