PITOCIN

By Dr Siak Bee Leng

INTRODUCTION

• Pitocin (oxytocin injection) is a sterile, clear, colorless aqueous solution of synthetic oxytocin

• Pitocin is a nonapeptide found in pituitary extracts from mammals.

• It is standardized to contain 10 units of oxytocic hormone/mL + 0.5% Chlorobutanol (a chloroform derivative as a preservative) with the pH adjusted with acetic acid.

• It acts rapidly with a latency period of less than 1 minute by IV injection, and of 2 to 4 minutes by IM injection.

• The oxytocic response lasts for 30 to 60 minutes after IM administration, possibly less after IV injection.

ANTEPARTUM

• Induction/augmentation of labor - -Double regime/incremental regime-- IVI 10units /500mls of NS, infuse at 2mlU/min, max

96mls/hour/32dpm• Treatment of incomplete/inevitable abortion-- IVI 5 IU over 5 minutes -- IM 5 to 10 IU, if necessary followed by IVI at a rate of

20 to 40 milliunits/minute or higher. • Total dose should not exceed 30 units in a 12-hour

period due to the risk of water intoxication

POSTPARTUM

• In third stage of labour(heart disease, hypertension, allergic syntometrium) to prevent PPH

-- IM 10 units after delivery of anterior shoulder-- IVI 5-20 units/500mls of NS over 6H• In casearean section (uterine tone)-- IV 3-5 units over 5 seconds• To treat postpartum haemorrhage>500ml : IVI 40 units/500mls of NS at 125ml/ hr>1L: IV 5 units bolus x 2

CONTRAINDICATIONS

Fetal• Fetal compromise• Unfavorable fetal positions

or presentations

Maternal • Uterine hypertonicity• Cephalopelvic disproportion• Hypersensitivity to oxytocin

OVERDOSE• Water intoxication with

seizures, cerebral edema, coma

• Tachycardic, bradycardic• Hypotension/

hypertension• Uterus tetanic, uterus

rupture• PPH• Premature ventricular

contraction

• Cardiac arrhythmias • Headache • Nausea/vomiting• Anaphylaxis• Disseminated

intravascular coagulation

• Pelvic hematoma (accumulation of blood in soft tissue of pelvis)

TREATMENT

• NO ANTIDOTE• The infusion must be discontinued at once and

oxygen should be given to the mother. • In water intoxication, restrict fluid intake,

promote diuresis, correct electrolyte imbalance; and control possible convulsions by judicious use of diazepam