Usage
Carbetocin is prescribed for the prevention of postpartum haemorrhage (PPH) due to uterine atony. It is a synthetic long-acting analogue of oxytocin. Its pharmacological classification is uterotonic agent. Carbetocin works by binding to oxytocin receptors in the uterine smooth muscle, stimulating uterine contractions.
Alternate Names
It is also known as long-acting oxytocin. Brand names include Duratocin, Pabal, and Carbetocin Ferring.
How It Works
Pharmacodynamics: Carbetocin mimics the action of endogenous oxytocin, causing sustained and powerful uterine contractions which helps to prevent PPH by reducing blood loss.
Pharmacokinetics:
- Absorption: Following intravenous (IV) administration, carbetocin reaches peak plasma concentrations rapidly. Intramuscular (IM) administration results in peak concentrations within 30 minutes, with a bioavailability of approximately 77%.
- Metabolism: Carbetocin is believed to be metabolized by peptidases.
- Elimination: Carbetocin demonstrates biphasic elimination with a terminal half-life of around 30 minutes after IV administration and approximately 55 minutes after IM administration. Small amounts are excreted in breast milk.
Mode of Action: Carbetocin acts as an agonist at oxytocin receptors in the myometrium. Binding triggers a cascade leading to increased intracellular calcium, ultimately resulting in myometrial contractions.
Elimination Pathways: Carbetocin is likely eliminated through both renal and hepatic pathways. Precise details on specific CYP enzyme involvement are limited.
Dosage
Standard Dosage
Adults:
A single dose of 100 micrograms (1 mL) is administered.
- Caesarean section: Administered intravenously over 1 minute after the infant’s delivery. Can be given before or after placental delivery.
- Vaginal delivery: Administered intramuscularly or intravenously over 1 minute after the infant’s delivery.
Children:
No pediatric dosage recommendations are available. Use is not intended for children under 12 years of age.
Special Cases:
- Elderly Patients: Not recommended for use in post-menopausal women.
- Patients with Renal Impairment: Not recommended, as pharmacokinetic data in this population is lacking.
- Patients with Hepatic Dysfunction: Not recommended, as pharmacokinetic data in this population is lacking.
- Patients with Comorbid Conditions: Use with caution in patients with cardiovascular disease, epilepsy, or migraine. Closely monitor blood pressure in patients with pre-eclampsia or eclampsia.
Clinical Use Cases
Carbetocin’s use is exclusively for preventing postpartum haemorrhage associated with uterine atony. It is not indicated for intubation, surgical procedures outside of childbirth, mechanical ventilation, general ICU use, or emergency situations like status epilepticus or cardiac arrest.
Dosage Adjustments
No specific dose adjustments are recommended apart from avoiding use in patients with renal or hepatic impairment.
Side Effects
Common Side Effects
Nausea, vomiting, abdominal pain, itching, flushing, feeling of warmth, fever, headache, dizziness, metallic taste, shivering, sweating, and back pain.
Rare but Serious Side Effects
Hypotension, irregular heartbeat, chest pain, fainting, palpitations.
Long-Term Effects
Limited data are available on long-term effects.
Adverse Drug Reactions (ADR)
Anaphylaxis, dyspnea, and other hypersensitivity reactions.
Contraindications
- Pregnancy and labor before infant delivery
- Induction or augmentation of labor
- Hypersensitivity to carbetocin or oxytocin
- Serious cardiovascular disorders
- Epilepsy
- Renal or hepatic impairment
Drug Interactions
- Caudal block anaesthesia with vasoconstrictors: Can cause severe hypertension.
- Ergot alkaloids (e.g., methylergometrine): May enhance hypertensive effects.
- Prostaglandins: May potentiate carbetocin’s effects.
- Inhalation anesthetics (e.g., halothane, cyclopropane): May enhance hypotensive effects and reduce uterine action.
Pregnancy and Breastfeeding
Pregnancy: Carbetocin is contraindicated during pregnancy and labor before infant delivery.
Breastfeeding: Small amounts are excreted in breast milk. While not expected to cause significant harm to the infant, data is limited.
Drug Profile Summary
- Mechanism of Action: Oxytocin receptor agonist, stimulating uterine contractions.
- Side Effects: Nausea, vomiting, headache, flushing, hypotension (rarely).
- Contraindications: Pregnancy, hypersensitivity, cardiovascular disease, epilepsy, renal/hepatic impairment.
- Drug Interactions: Caudal block anaesthesia with vasoconstrictors, ergot alkaloids, prostaglandins, inhalation anesthetics.
- Pregnancy & Breastfeeding: Contraindicated in pregnancy. Small amounts excreted in breast milk.
- Dosage: 100 mcg IV or IM single dose after delivery.
- Monitoring Parameters: Blood pressure, uterine tone, bleeding.
Popular Combinations
It is not typically used in combination with other drugs for the prevention of PPH. If bleeding persists despite carbetocin administration, other uterotonics may be necessary.
Precautions
- General Precautions: Administer in a setting with trained obstetric personnel. Monitor closely for persistent bleeding.
- Specific Populations: Avoid use in patients with pre-existing conditions mentioned under contraindications.
- Lifestyle Considerations: No specific lifestyle considerations are associated with carbetocin’s short-term use.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Carbetocin?
A: A single dose of 100 micrograms IV or IM after delivery. No further doses should be given.
Q2: Can Carbetocin be used to induce labor?
A: No, carbetocin is contraindicated for labor induction or augmentation.
Q3: How is Carbetocin administered?
A: IV administration should be slow over 1 minute. IM administration can also be used for vaginal deliveries.
Q4: What are the common side effects?
A: Nausea, vomiting, headache, and flushing are the most common side effects.
Q5: Can carbetocin be used in patients with renal failure?
A: No, carbetocin is not recommended in patients with renal or hepatic impairment.
Q6: What should be done if bleeding continues after Carbetocin administration?
A: Investigate the cause of bleeding (e.g., retained placental fragments, lacerations). Other uterotonic agents may be required.
Q7: Can Carbetocin be given before the baby is delivered?
A: No, carbetocin should only be given after the baby is delivered.
Q8: How does carbetocin differ from oxytocin?
A: Carbetocin has a longer duration of action than oxytocin, requiring only a single dose compared to a continuous infusion of oxytocin.
Q9: Can carbetocin be used during a Cesarean section?
A: Yes, carbetocin is indicated for preventing PPH after both vaginal and cesarean deliveries.
Q10: Are there any drug interactions I should be aware of?
A: Yes, see the “Drug Interactions” section for details. Pay close attention to concomitant use with caudal block anaesthesia with vasoconstrictors.
This information is current as of February 16, 2025, and may be subject to change. Always consult the latest medical references and guidelines for the most up-to-date information.
