Pharmaceutical in obg

1. Pharmacotherapeutics in obg
Analgesics and anaesthesia

2. SEDATIVES AND ANALGESICS
• 1. OPIOID ANALGESICS: PETHIDINE
• Mechanism of action: Inhibits ascending pain
pathways in CNS , increase pain threshold and
alters pain perception.
• Indications: Moderate to severe pain in labour,
postoperative pain, abruption placentae,
pulmonary edema.
• Dose: Injectable preparations contains 50mg/ml
can be administered SC, IM,IV. Its dose is 50-100
mg IM combined with promethazine.

3. • PETHIDINE Contraindications:
*Should not be used IV within 2 hrs and IM
within 3 hrs of expected time of delivery of the
baby, for fear of birth asphyxia.
* It should not be used in cases of preterm
labour and when respiratory reserve of the
mother is reduced

4. • Side effects:
• Maternal
• Drowsiness
• Dizziness
• Confusion
• Headache
• Sedation
• Nausea
• Vomiting
• Fetal Respiratory depression Asphyxia

5. • FENTANYL Mechanism of action:
• Inhbits ascending pathways in CNS, increases
pain threshold and alters pain perception.
• Indications: Moderate to severe pain in labour,
post operative apin an dadjunct to general
anaesthetic.
• Dose: 0.05 to 0.1 mg IM q1-2 hrs prn. Available
in injectable form, 0.05 mg/ml.
• . Side effects: Dizziness Delirium Euphoria
Nausea Vomiting Muscle rigidity Blurred
vision

6. • PENTACOZIN
• dose of 30-40 mg
• Naloxone is an efficient and reliable antagonist.
• Adverse effects
• Neonate respiratory depression secondary to the
medication crossing the placenta and affecting
the fetus.
• Unsteady ambulation of the client.
• Inhibition of the mother’s ability to cope with
the pain of labor.

7. TRANQUILIZERS
• DIAZEPAM:Usual dose is 5-10 mg.
• MIDAZOLAM:Dose of 0.05 mg/kg is given
intravenously
• COMBINATION OF NARCOTICS AND
TRANQUILIZERS
• BUTORPHANOL and NALBUPHINE

8. INHALATIONAL METHODS
• Nitrous oxide and air
• Premixed nitrous oxide and oxygen
Trichloroethylene
• Methoxyflurane, isoflurane, enflurane

9. EPIDURAL AND SPINAL REGIONAL
ANALGESIA
• Adverse effects
• nausea and vomiting.
• Inhibition of bowel and bladder elimination
sensations.
• Bradycardia or tachycardia.
• Hypotension.
• Respiratory depression.
• Allergic reaction and pruritus.

10. PUDENDAL BLOCK
• It consists of a local anesthetic such as
lidocaine(Xylocaine) or bupivacaine
(Marcaine) being administered transvaginally
into the space in front of the pudendal nerve.

11. EPIDURAL ANAESTHESIA
• Epidural block consists of a local anesthetic
bupivacaine (Marcaine) along with an
analgesic morphine (Duramorph) or fentanyl
(Sublimaze) injected into the epidural space at
the level of the fourth of fifth vertebrae.
• Adverse effects Maternal hypotension.
Fetal bradycardia. Inability to feel the urge
to void. Loss of the bearing down reflex.

12. • SPINAL BLOCK Spinal block consists of a local
anaesthetic injected into the subarachnoid
space into the spinal fluid at the third, fourth,
or fifth lumbar interspace, alone or in
combination with an analgesic such as
fentanyl .
• Adverse effects
• Maternal hypotension. Fetal bradycardia.
Loss of the bearing down reflex.

13. PARACERVICAL BLOCK
• It consists of lidocaine (Xylocaine) being
injected into the cervical mucosa early in labor
during the first stage to block the pain of
uterine contractions.
• Adverse effects include fetal bradycardia.
Improper technique can result in serious
toxicity.

14. GENERAL ANAESTHESIA
• 100% oxygen is administered by tight mask fit
for more than 3 minutes.
• Induction of anaesthesia is done with the
injection of thiopentone sodium 200- 250 mg as a
2.5 % solution IV.,followed by refrigerated
suxamethonium 100 mg.
• the patient is intubated with cuffed ET tube.
Anaesthesia is maintained with 50% NO2 , 50%
oxygen and a trace of halothane.
• Relaxation is maintained with non- depolarizing
muscle relaxant [ vecuronium 4 mg or atracurium
25 mg].