Uterine contracting agents

Carboprost has been used successfully to control postpartum bleeding that was secondary to loss of uterine tone and where the myometrium was unresponsive to oxytocin, ergonovine, or methylergonovine. Given intramuscularly, carboprost causes an almost immediate and sustained uterine contraction. Clinical experience has shown that the use of this agent has saved many women from operative interventions (including hysterectomy) to control postpartum hemorrhage. 

This agent is used due to certain advantages i.e. it provides profound analgesia and good relaxation of skeletal muscles, uterine contractions are not inhibited and postoperative nausea and vomiting are not troublesome. But, due to its renal toxicity, its use as a general anaesthetic is limited. 

Q9 Outline the actions of pharmacological agents that can be used to diminish premature uterine contractions, which may occur before gestation is complete. 

Inhibition of natural or induced uterine contractions by halothane during parturition may prolong the process of delivery, as well as increase blood loss. Thus, other agents or techniques may be preferred for the relief of obstetrical pain. 

Structure and properties of the naturally occuring prostaglandins and their precursors have been reviewed by Ramwell et al. [85]. The PGE s are vasodepressor agents, inhibit uterine contraction but, on the other hand, increase cardiac output and induce contraction of intestinal smooth muscle. They exhibit marked antilipolytic activity. PGE is rapidly removed from the blood and it disappears already in one circulation, particularly through the lung [86]. 

Sparteine was withdrawn by the U.S. FDA as an injectable drug because of its ability to produce titanic uterine contractions and its unpredictability. Due to the tyramine content of the herb, use may cause blood pressure crisis with simultaneous administrations of MAO inhibitors (blumenthal 1) due to the ability of the herb to increase the tonus of the gravid uterus, use is contraindicated in pregnancy sparteine is a potent oxytocic agent broom tops is also contraindicated in patients with high blood pressure (newall wichtl). The oral LD50 of sparteine in mice is 220mg/kg. ... 

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