In obstetrics, various drugs are used to manage labor, induce labor, provide analgesia, and manage potential complications. Below is an overview of some commonly used drugs in obstetrics, followed by their doses, routes, side effects, nursing implications, and mechanisms of action.
1. Oxytocin (Pitocin)
- Drug Class: Uterotonics
- Use: Induction and augmentation of labor.
- Dose:
- Initiate infusion at 0.5 to 2 mU/min; may increase by 1-2 mU/min every 30-60 minutes based on uterine response.
- Route: Intravenous (IV) infusion.
- Side Effects: Uterine hyperstimulation, water retention, hypotension, tachycardia, and potential fetal distress.
- Nursing Implications:
- Monitor fetal heart rate and uterine contractions.
- Assess for signs of uterine hyperstimulation.
- Maintain IV site and ensure proper titration of medication.
- Mode of Action: Stimulates uterine smooth muscle contractions, facilitating labor.
2. Methotrexate
- Drug Class: Antimetabolite
- Use: Medical management of ectopic pregnancy.
- Dose: Generally 50 mg/m² IM (intramuscular) as a single dose.
- Route: Intramuscular, may be given in divided doses depending on the protocol.
- Side Effects: Nausea, vomiting, abdominal pain, fatigue, and potential for bone marrow suppression.
- Nursing Implications:
- Monitor for signs of adverse reactions.
- Assess for resolution of ectopic pregnancy through follow-up hCG levels.
- Educate the patient about signs of complications.
- Mode of Action: Inhibits cell replication, primarily affecting rapidly dividing cells like those in ectopic tissues.
3. Magnesium Sulfate
- Drug Class: Tocolytics, neuroprotective agent
- Use: Prevention and management of preterm labor and for neuroprotection in preterm infants.
- Dose: Typically, a loading dose of 4-6 g IV over 20-30 minutes, followed by a maintenance infusion of 1-2 g/hour.
- Route: Intravenous infusion.
- Side Effects: Flushing, sweating, hypotension, and potential respiratory depression.
- Nursing Implications:
- Monitor maternal and fetal vital signs.
- Assess deep tendon reflexes and signs of toxicity (e.g., respiratory depression, urine output).
- Mode of Action: Relaxes smooth muscle, inhibits uterine contractions, and protects the fetal brain from potential injury during preterm labor.
4. Bupivacaine (Marcaine)
- Drug Class: Local anesthetic
- Use: Epidural or spinal anesthesia during labor and delivery.
- Dose: Epidural: 0.1% to 0.25% concentration; spinal: 0.5% to 0.75%.
- Route: Epidural or spinal injection.
- Side Effects: Hypotension, motor block, headache (postdural puncture), and risk of infection at the site.
- Nursing Implications:
- Monitor maternal blood pressure.
- Assess for motor and sensory block (e.g., level of anesthesia).
- Ensure appropriate patient positioning during administration.
- Mode of Action: Blocks sodium channels, inhibiting nerve conduction and resulting in loss of sensation in targeted areas.
5. Fentanyl
- Drug Class: Opioid analgesic
- Use: Pain management during labor.
- Dose: 50-100 mcg IV (may be given in increments based on need).
- Route: Intravenous; may also be used in epidural or intrathecal settings.
- Side Effects: Respiratory depression, sedation, nausea, constipation.
- Nursing Implications:
- Assess pain level and monitor for signs of respiratory depression.
- Continuously monitor maternal vital signs and fetal heart rate.
- Mode of Action: Binds to opioid receptors in the brain, altering the perception and response to pain.
6. Rho(D) Immunoglobulin (RhoGAM)
- Drug Class: Immune globulin
- Use: Prevention of Rh immunization in Rh-negative mothers.
- Dose: 300 mcg IM within 72 hours after delivery or any potential Rh sensitization.
- Route: Intramuscular injection.
- Side Effects: Localized pain at the injection site, mild fever, and allergic reactions (rare).
- Nursing Implications:
- Ensure maternal blood type has been confirmed.
- Administer on time to prevent Rh sensitization.
- Mode of Action: Prevents the mother from developing antibodies against Rh-positive blood cells.
This is a simplified overview of some common drugs used in obstetrics. Each drug's use and implication can vary based on specific clinical scenarios and guidelines. Always refer to updated clinical guidelines and institutional protocols for the most accurate and comprehensive information.