DRUGS COMMONLY USED DURING LABOUR

DRUGS COMMONLY USED DURING LABOUR – CHEMICAL COMPOSITION, INDICATION, CONTRAINDICATION, MODE OF ACTION, DOSAGE, SHELF LIFE, COMPLICATIONS & GUIDELINES FOR USE

Labour is a complex physiological process involving uterine contractions, cervical dilation, and fetal expulsion. Certain drugs are commonly used to facilitate or manage the stages of labour. These drugs have specific chemical compositions, indications, contraindications, and complications. Ayurveda mentions the use of various herbal preparations to promote safe delivery, while modern obstetrics employs pharmacotherapeutic agents such as oxytocin, prostaglandins, tocolytics, and analgesics.

AYURVEDIC PERSPECTIVE ON LABOUR MANAGEMENT

SANSKRIT SHLOKAS WITH REFERENCES

गर्भिण्याः प्रसवो यस्यां नानुपपन्नोऽर्थवत्यपि।
गर्भं चास्या न निर्गच्छेत् तस्या दोषातिसङ्गतः॥
— Charaka Samhita, Sharira Sthana 8/32

प्रसूतिवेलायां योषितां
युक्तं बलवर्णवर्धनम्।
दातव्यमौषधं काले
प्रसूतीनां हितं स्मृतम्॥
— Ashtanga Hridaya, Uttara Tantra 2/23

Ayurveda prescribes specific preparations like Erandamoola Kashaya, Yavakshara, Sukumara Ghrita, Sarpagandha, and Ashwagandha to aid uterine contractions or relaxation, support maternal strength, and manage labour pain. These are to be used under proper clinical guidance.

MODERN DRUGS COMMONLY USED DURING LABOUR

OXYTOCIN

CHEMICAL COMPOSITION

• Synthetic analogue of the natural hormone oxytocin.

• Chemical formula: C₄₃H₆₆N₁₂O₁₂S₂

INDICATIONS

• Induction or augmentation of labour

• Management of postpartum hemorrhage (PPH)

• Facilitate uterine contractions after delivery

CONTRAINDICATIONS

• Cephalopelvic disproportion

• Malpresentation

• Fetal distress

• Placenta previa

MODE OF ACTION

• Binds to oxytocin receptors in the myometrium, increasing intracellular calcium and enhancing uterine contractions.

DOSAGE

• Induction: 1–2 mU/min IV infusion, increased every 15–30 mins

• PPH: 10 IU IM or 20–40 IU in 1L NS IV infusion

SHELF LIFE

• 24 months if stored at 2–8°C

COMPLICATIONS

• Uterine hyperstimulation

• Fetal distress

• Water intoxication

• Hypotension

GUIDELINES FOR USE

• Use only in hospital setting with continuous fetal monitoring

• Never combine with other uterotonics simultaneously

• Avoid bolus IV injection

MISOPROSTOL (PROSTAGLANDIN E1 ANALOGUE)

CHEMICAL COMPOSITION

• Synthetic prostaglandin E1 analogue

• Chemical formula: C₂₂H₃₈O₅

INDICATIONS

• Cervical ripening

• Labour induction

• Postpartum hemorrhage management

CONTRAINDICATIONS

• Previous cesarean scar (risk of rupture)

• Hypersensitivity

• Active cardiac or renal disease

MODE OF ACTION

• Stimulates uterine smooth muscle contraction and cervical softening

DOSAGE

• Induction: 25 mcg vaginally every 4–6 hours

• PPH: 600–800 mcg rectally

SHELF LIFE

• 3 years at room temperature

COMPLICATIONS

• Uterine rupture (especially in scarred uterus)

• Fever, chills, diarrhea

• Hypertonic uterine contractions

GUIDELINES FOR USE

• Use lowest effective dose

• Avoid use in women with previous uterine surgery

• Monitor vitals and uterine activity

DINOPROSTONE (PROSTAGLANDIN E2)

CHEMICAL COMPOSITION

• Prostaglandin E2

• Chemical formula: C₂₀H₃₂O₅

INDICATIONS

• Cervical ripening before labour induction

CONTRAINDICATIONS

• Asthma

• Glaucoma

• Scarred uterus

• Placenta previa

MODE OF ACTION

• Promotes collagen degradation in cervix and stimulates uterine contractions

DOSAGE

• 0.5 mg intracervical gel; may repeat every 6 hours

• Vaginal insert: 10 mg (releases 0.3 mg/hr over 12 hours)

SHELF LIFE

• 2 years when refrigerated

COMPLICATIONS

• Nausea, vomiting

• Uterine tachysystole

• Fetal bradycardia

GUIDELINES FOR USE

• Monitor uterine activity and fetal heart rate

• Avoid oxytocin for at least 6 hours after last dose

METHERGINE (METHYLERGONOVINE MALEATE)

CHEMICAL COMPOSITION

• Semi-synthetic ergot alkaloid

• Chemical formula: C₂₀H₂₅N₃O₂

INDICATIONS

• Prevention and treatment of postpartum hemorrhage

CONTRAINDICATIONS

• Hypertension

• Pre-eclampsia

• Peripheral vascular disease

MODE OF ACTION

• Directly stimulates uterine and vascular smooth muscle

DOSAGE

• 0.2 mg IM after delivery of anterior shoulder; repeat if needed every 2–4 hours

SHELF LIFE

• 2–3 years at room temperature

COMPLICATIONS

• Hypertension

• Nausea

• Headache

• Vasoconstriction

GUIDELINES FOR USE

• Never administer IV as bolus

• Monitor blood pressure

• Avoid in hypertensive disorders of pregnancy

MAGNESIUM SULFATE

CHEMICAL COMPOSITION

• Inorganic salt (MgSO₄)

INDICATIONS

• Neuroprotection in preterm labour

• Management of eclampsia

• Tocolysis (rare use)

CONTRAINDICATIONS

• Myasthenia gravis

• Renal failure

• Heart block

MODE OF ACTION

• Blocks neuromuscular transmission; reduces uterine contractility at high doses

DOSAGE

• Loading: 4 g IV over 20 mins

• Maintenance: 1–2 g/hr IV infusion

SHELF LIFE

• 2–3 years at room temperature

COMPLICATIONS

• Respiratory depression

• Loss of reflexes

• Hypotension

• Flushing

GUIDELINES FOR USE

• Monitor reflexes, respiratory rate, and urine output

• Antidote: Calcium gluconate

TRAMADOL, PETHIDINE (LABOUR ANALGESIA)

CHEMICAL COMPOSITION

• Tramadol: synthetic opioid

• Pethidine: phenylpiperidine derivative

INDICATIONS

• Pain relief during labour

CONTRAINDICATIONS

• Respiratory depression

• Severe liver disease

MODE OF ACTION

• Act on opioid receptors in CNS to block pain pathways

DOSAGE

• Tramadol: 50–100 mg IM

• Pethidine: 50–100 mg IM

SHELF LIFE

• 2–3 years

COMPLICATIONS

• Nausea

• Sedation

• Neonatal respiratory depression

GUIDELINES FOR USE

• Use with caution in late stages of labour

• Always have neonatal resuscitation setup ready

GENERAL GUIDELINES FOR PHARMACOTHERAPEUTICS IN LABOUR

• Obtain informed consent before administration.

• Use drugs only when clinically indicated.

• Monitor maternal vitals and fetal heart rate continuously.

• Avoid combining uterotonics unless specifically indicated.

• Be aware of interactions and hypersensitivity.

• Ensure proper aseptic technique during administration.

• Maintain emergency drugs and neonatal resuscitation kits.

• Avoid unnecessary or prolonged use of labour-inducing drugs.