1	OB/GYN Emergency Pharmacology
2	Obstetrical and Gynecological Emergencies Prehospital care is usually supportive Three complications that require intervention: Hypertensive disorders of pregnancy Severe vaginal bleeding Preterm labor
3	Labor Induction & Severe Vaginal Bleeding
4	Oxytocin Pitocin
5	Class Hormone and uterine stimulant
6	Description Naturally occurring hormone that is secreted by the posterior pituitary
7	Mechanism of Action Causes contraction of uterine smooth muscle and lactation Induces labor in selected cases Induces uterine contractions following delivery Thereby controlling postpartum hemorrhage
8	Pharmacokinetics Onset Immediate (IV), 3-7 minutes (IM) Peak effects Variable Duration 1 hour (IV), 2-3 hours (IM) Half-life 3-5 minutes
9	Indications Postpartum hemorrhage
10	Contraindications Only administered to patients suffering severe postpartum bleeding Verify the baby and placenta have been delivered and that there is not an additional fetus in the uterus
11	Precautions Excess oxytocin can cause over-stimulation of the uterus and possible uterine rupture. Vital signs and uterine tone should be monitored.
12	Side Effects In the mother: Hypotension Dysrhythmias Tachycardia Seizures Coma Nausea and vomiting May have ADH effects at higher doses Water retention Vasoconstriction
13	Side Effects (cont.) If given prior to delivery, in the fetus: Fetal hypoxia Fetal asphyxia Fetal arrhythmias Fetal intracranial bleeding
14	Interactions Can cause hypertension when administered in conjunction with vasoconstrictors such as norepinephrine
15	Dosage Two different regimens in the management of postpartum hemorrhage Method 1: 3-10 units IM after delivery of the placenta Method 2: 10-20 units in 500 or 1000 mL of any solution Titrated to the severity of the bleeding and the uterine response
16	Hypertensive Disorders of Pregnancy
17	Hypertensive Disorders of Pregnancy Formerly called “toxemia of pregnancy” Characterized by: Hypertension Weight gain Edema Protein in the urine In late stages, seizure
18	Hypertensive Disorders of Pregnancy (cont.) Gestational hypertension (GH) Blood pressure of 140/90 level or greater Patient who was previously normotensive Preeclampsia Hypertension, abnormal weight gain, edema, headache, and visual disturbances If untreated, may progress to eclampsia
19	Hypertensive Disorders of Pregnancy (cont.) Eclampsia Most serious of the hypertensive disorders Characterized by grand mal seizure activity Often preceded by visual disturbances Can be distinguished from epilepsy by the history and physical exam
20	Magnesium Sulfate
21	Class Electrolyte
22	Description A salt that dissociates into the magnesium cation (Mg²⁺) and the sulfate anion when administered Magnesium is an essential element in numerous biochemical reactions that occur within the body.
23	Mechanism of Action Central nervous system depressant effective in the management of seizures associated with eclampsia After cessation of seizure activity, other anticonvulsant agents may be used
24	Pharmacokinetics Onset Immediate (IV), 1 hour (IM) Peak effects Variable Duration 1 hour Half-life N/A
25	Indications Eclampsia Preterm labor
26	Contraindications Patients who are in shock Persistent, severe hypertension Third-degree atrioventricular (AV) block Patients who routinely undergo dialysis Known decreased calcium levels
27	Precautions Administer slowly to minimize side effects Use continuous cardiac monitoring Calcium salts should be available as an antidote for magnesium sulfate in case serious side effects occur.
28	Side Effects Flushing Sweating Bradycardia Decreased deep tendon reflexes Drowsiness Respiratory depression Dysrhythmias Hypotension Hypothermia Itching and rash
29	Interactions Can cause cardiac conduction abnormalities if administered in conjunction with digitalis
30	Dosage 2-4 g slow IV over 25 minutes If an IV cannot be started, administer IM Dose should be divided in half Each half administered intramuscularly at a separate site (usually each gluteus)
31	Preterm Labor
32	Preterm Labor Labor that begins before the age of fetal maturity Usually before 36 weeks Often suppressed to allow more time for intrauterine fetal development
33	Preterm Labor (cont.) Three approaches to suppression: Sedate the mother Administration of a fluid bolus 1-2 L of lactated Ringer’s Administration of tocolytics β₂-agonists frequently used Causes uterine relaxation
34	Terbutaline
35	Class Sympathetic agonist and tocolytic
36	Description A synthetic sympathomimetic that is selective for β₂-adrenergic receptors
37	Mechanism of Action Causes immediate bronchodilation with minimal cardiac effects Stimulation of β₂-adrenergic receptors in the uterus causes uterine relaxation and can suppress labor.
38	Pharmacokinetics Onset < 15 minutes (SC) Peak effects 30-60 minutes (SC) Duration 1.5-4.0 hours (SC) Half-life 3-4 hours
39	Indications Preterm labor
40	Contraindications Known history of hypersensitivity
41	Precautions Caution should be used with: Elderly patients Cardiovascular disease Hypertension V/S must be monitored
42	Side Effects Palpitations Anxiety Dizziness Headache Nervousness Tremor Hypertension Dysrhythmias Chest pain Nausea and vomiting
43	Interactions Unpleasant side effects increase when used with other sympathetic agonists β-blockers may blunt the pharmacological effects of terbutaline
44	Dosage Initial dose should be 0.25 mg SC Can be repeated in 30-60 minutes Maintenance drip can be used Placing 5 mg in 500 mL of lactated Ringer’s solution or normal saline 30 mL/hr (5 mg/min) Can be slowly increased to a maximum dose of 80 mg/min
45	Summary