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Carbetocin (Duratocin/Pabal)9 residues (approx.)CYITNCPLGEach bubble = one amino acid. Size = residue mass. Color = chemical class.Uses closest standard amino acids for non-standard residues.Also known as: Pabal, Duratocin, sdOT
Nearly 30,000 women across 10 countries proved it works. Carbetocin (sold as Pabal in Europe and Duratocin in Canada) is a synthetic oxytocin analog built for one job: preventing postpartum hemorrhage after delivery. One injection. One fixed dose. Sixty minutes of sustained uterine contraction, compared to roughly 15 minutes from standard oxytocin. The CHAMPION trial [1] earned it a spot on the WHO Essential Medicines List in 2019, and it's now approved in over 40 countries. The catch: the FDA hasn't approved it, so US patients don't have access. For the rest of the world, it's become a cornerstone of obstetric care.
One injection, sixty minutes of protection. That's the clinical pitch for carbetocin, an octapeptide synthetic analog of oxytocin (CAS 37025-55-1) marketed as Pabal in Europe and Duratocin in Canada. The structural trick is simple on paper but took decades to engineer. Replacing the native disulfide bridge with a thioether linkage and deaminating the cysteine at position 1 makes the molecule resistant to oxytocinase, the enzyme that chews through natural oxytocin in minutes. The result: a half-life of 33 to 55 minutes depending on route, compared to oxytocin's 3 to 5 minutes. Clinicians use it for exactly one thing. After delivery of the infant, a single 100 mcg dose (IV for cesarean, IM for vaginal birth) triggers sustained rhythmic uterine contractions that prevent the uterine atony responsible for most postpartum hemorrhage. No titration. No infusion pump. No repeat dosing. The evidence base is strong. The WHO-led CHAMPION trial enrolled 29,645 women across 23 sites in 10 countries and confirmed non-inferiority to oxytocin 10 IU IM for preventing blood loss of 500 mL or greater after vaginal birth [1]. A 2025 systematic review covering 30 publications found carbetocin superior to misoprostol on blood loss outcomes (PMC12145113). Multiple RCTs in cesarean settings show it reduces the need for rescue uterotonics by 30 to 50 percent. Carbetocin holds approval in over 40 countries, including EU member states, Canada, Australia, and Singapore. The heat-stable formulation, which doesn't need refrigeration below 30 degrees Celsius, landed on the WHO Essential Medicines List in 2019. The FDA has not approved carbetocin; it remains classified as a research compound in the US market.
Carbetocin binds the oxytocin receptor (OXTR), a Gq-coupled receptor packed densely across myometrial smooth muscle during late pregnancy and the immediate postpartum window. Receptor activation triggers phospholipase C-beta, which hydrolyzes PIP2 into IP3 and DAG. IP3 dumps calcium from the sarcoplasmic reticulum; DAG fires up protein kinase C. Both pathways converge on actin-myosin cross-bridge cycling to produce sustained contraction. Two things set carbetocin apart from oxytocin at the receptor level. First, it's a functionally selective Gq agonist with minimal activity at vasopressin V1a or V1b receptors [2]. That selectivity likely explains the slightly cleaner cardiovascular profile. Second, and this is the mechanistic detail that matters most clinically, carbetocin triggers beta-arrestin-independent internalization of the OXTR. Once the receptor pulls inside the cell, it stays there. It does not recycle back to the membrane the way it does after oxytocin stimulation. That means the receptor keeps signaling from endosomal compartments while the cell surface clears. Sustained intracellular signaling without desensitization-resensitization cycling; roughly 60 minutes of contractile activity from a single dose. The structural modifications (deaminated position 1, thioether bridge replacing the disulfide bond) block degradation by oxytocinase and other serum peptidases. Plasma half-life extends 4 to 10 fold over native oxytocin. An additional contractile pathway runs through COX-2 upregulation. OXTR activation increases local prostaglandin F2-alpha production, adding a calcium-independent myometrial stimulus on top of the direct Gq pathway.
WHO-approved pharmaceutical (40+ countries; EU as Pabal, Canada as Duratocin) for PPH prevention after cesarean or vaginal delivery. CHAMPION trial (NEJM 2018, n=29,645) demonstrated non-inferiority to oxytocin 10 IU IM for blood loss ≥500 mL and need for additional uterotonics after vaginal birth. 2025 systematic review (PMC12145113, 30 publications) confirms superiority to misoprostol on blood loss outcomes. Single fixed 100 mcg dose is the only approved regimen.
CHAMPION trial (NEJM 2018, PMID 29949473, n=29,645); 2025 systematic review of 30 publications (PMC12145113)
Not FDA-approved in the US; no US pricing or clinical access. Non-inferiority for harder endpoint (blood loss ≥1,000 mL) not conclusively demonstrated in CHAMPION. Intranasal carbetocin for Prader-Willi Syndrome (Acadia ACP-101 COMPASS Phase 3, n=175) failed September 2025: neuropsychiatric indication not viable. WHO REACH trial (PPH treatment use, not prophylaxis) ongoing with no results published as of April 2026.
No community use exists. Carbetocin is a hospital-only obstetric pharmaceutical with no self-administration, biohacking, or off-label consumer protocols. Zero Reddit/forum activity found across r/peptides, r/TTC, and related communities.
No community use exists: carbetocin is an IV/IM obstetric pharmaceutical administered exclusively in hospital delivery suites. The science-only classification reflects the complete absence of any self-administration or community-protocol context, not a divergence in scientific opinion.
| Level | Dose / Injection | Frequency |
|---|---|---|
| Beginner | 100mcg | Single dose |
| Moderate | 100mcg | Single dose |
| Aggressive | 100mcg | Single dose |
Carbetocin comes ready to use. No reconstitution, no BAC water, no math. Each vial or ampoule contains 100 mcg in 1 mL of solution. You draw up the full 1 mL and that's the dose. For IV (cesarean): push the entire 1 mL slowly over exactly one minute. Not 30 seconds, not a fast bolus. Slow push prevents the transient hypotension that catches people off guard. For IM (vaginal delivery): inject the full 1 mL into the deltoid or thigh. Bioavailability drops to about 77 percent via IM, but peak uterotonic effect is comparable. IM onset runs slower; expect peak plasma at roughly 30 minutes. The non-obvious thing most people miss: you cannot give a second dose. The receptor internalizes after carbetocin and won't come back. If the uterus stays boggy past 60 minutes, switch to a completely different drug class. Heat-stable vials store below 30 degrees Celsius without refrigeration. Standard formulation needs cold chain. Check the vial label.
Carbetocin is not used in a cycling protocol. It is administered as a single dose exclusively in the immediate postpartum period to prevent uterine atony and hemorrhage. No repeat dosing or long-term use is indicated. If additional uterotonic support is needed after carbetocin, alternative agents (oxytocin infusion, ergometrine, or prostaglandins) should be used rather than a second dose of carbetocin.
Carbetocin is not a cycled compound. A single 100 mcg dose is the complete and maximal clinical course. Repeat dosing is not indicated and would add risk without benefit: carbetocin induces beta-arrestin-independent OXTR internalization, and once internalized the receptor does not recycle to the plasma membrane. A second dose cannot meaningfully re-engage myometrial receptors. Any additional uterotonic support after carbetocin must use a different agent (oxytocin infusion, ergometrine, misoprostol).
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Expected: IV onset within 2 min; IM peak effect at ~30 min. Sustained rhythmic uterine contractions for ~60 min. Reduces need for additional uterotonic rescue agents by 30–50% vs. standard care. Non-inferior to oxytocin 10 IU IM for PPH prevention after vaginal birth (CHAMPION trial, n=29,645).
Monitor: Maternal BP and pulse every 15 min for at least 1 hour post-dose. Uterine tone via fundal palpation every 15–30 min. Observe for transient flushing, tachycardia, hypotension (especially after IV). Anaphylaxis monitoring for first 30 min. Quantitative blood loss assessment peripartum.
Carbetocin is strictly a postpartum agent. Never administer before delivery.
Draw up the full 1 mL from the single-use 100 mcg/mL vial using a standard syringe. No dilution needed.
Do not mix carbetocin with other medications in the same syringe.
The vial is single-use only. Do not store opened vials.
Monitor maternal blood pressure and pulse every 15 minutes for at least 1 hour. Palpate the uterine fundus every 15 to 30 minutes to confirm adequate tone.
If uterine atony persists beyond 60 minutes, do not give a second carbetocin dose. Escalate per institutional PPH protocol: oxytocin infusion, ergometrine, misoprostol, or tranexamic acid.
Step 3 (Cesarean / IV route). With IV access established, inject the full 1 mL slowly over exactly 1 minute. Count it out. Rapid bolus causes transient hypotension and tachycardia. Administer before placental delivery if possible.
Step 3 (Vaginal delivery / IM route). Inject the full 1 mL intramuscularly into the deltoid or lateral thigh. The IM route is preferred when IV access isn't immediately available; bioavailability is approximately 77 percent.
100 mcg: identical dose to IM; IV t½ ~33 min (0.55h); faster onset and slightly shorter duration
Must be injected slowly over exactly 1 minute. Rapid bolus causes transient hypotension and tachycardia. Preferred intraoperatively when IV access is already established. Give as dedicated slow push: do not add to IV infusion bag.
100 mcg: identical dose to IV; IM t½ ~55 min (0.92h); bioavailability ~77%; slower onset, peak plasma at ~30 min
IM route is logistically simpler: no IV line required; important for LMIC birth attendant training. Heat-stable formulation is particularly valuable for IM delivery in settings without cold-chain infrastructure.
Antifibrinolytic increasingly bundled with uterotonics in PPH management. WHO recommends TXA 1 g IV within 3h of PPH onset. Clinical practice uses carbetocin prophylaxis → TXA as treatment escalation in a sequential bundle; not co-administered prophylactically.
TXA 1 g IV at PPH diagnosis (blood loss ≥500 mL or clinical concern); sequential with carbetocin, not co-administered at delivery
Atosiban is a competitive oxytocin receptor (OTR) antagonist: directly opposes carbetocin's OTR agonism at the same receptor. Concurrent use negates the uterotonic effect of carbetocin. These agents are pharmacological opposites.
Do not combinePer Pabal SmPC: may enhance hypertensive effects when used concomitantly with carbetocin. Allow adequate time interval if sequential uterotonic use is required. Particularly relevant for patients with hypertension or pre-eclampsia.
Per Pabal SmPC: may potentiate uterotonic effect, increasing risk of uterine hyperstimulation. Use as escalation only if carbetocin effect is insufficient, not as routine co-prophylaxis.
Per Pabal SmPC: may enhance hypotensive effects and weaken the uterotonic response to carbetocin. Intraoperative clinical vigilance required during cesarean under inhalational anesthesia.
Pricing updated 2026-04-09
The most serious risk with carbetocin is cardiovascular: transient hypotension and tachycardia after IV administration, reported in 1 to 10 percent of patients per the Pabal SmPC. Rapid IV bolus makes this worse. The drug must be injected slowly over exactly one minute; faster delivery produces clinically meaningful drops in blood pressure. Carbetocin also carries antidiuretic properties similar to oxytocin. Excessive fluid intake combined with the drug's effects can theoretically cause water intoxication and hyponatremia. The single-dose protocol largely mitigates this, since there's no prolonged infusion pushing free water retention. But it's worth noting for patients already receiving large-volume IV fluids during delivery. Serious cardiovascular disorders and cardiac rhythm disturbances are listed contraindications. Carbetocin has not been formally evaluated in eclampsia or severe pre-eclampsia, so it should be used with caution in those populations. Common side effects (1 to 10 percent incidence) tracked across clinical trials and the Pabal SmPC include headache, tremor, nausea, vomiting, abdominal pain, flushing, feeling of warmth, and metallic taste. Anemia appears in over 10 percent of recipients, though that largely reflects the delivery context itself rather than a direct drug effect. Uncommon to rare reactions include dizziness, chest pain or tightness, dyspnea, pruritus, and back pain. Allergic or hypersensitivity reactions are rare but documented. Anaphylaxis resuscitation equipment must be immediately available for the first 30 minutes after dosing. A critical pharmacological safety point: do not repeat the dose. After carbetocin binds the OXTR, the receptor internalizes and does not return to the cell surface. A second dose of carbetocin has no receptor to act on. If uterine atony persists beyond 60 minutes, the correct escalation is a different uterotonic agent (oxytocin infusion, ergometrine, misoprostol, or tranexamic acid) per institutional PPH protocol. Drug interactions deserve attention in the obstetric setting. Ergot alkaloids (methylergometrine, ergometrine) may amplify hypertensive effects. Prostaglandins (misoprostol, dinoprostone) can potentiate the uterotonic effect and risk uterine hyperstimulation. Inhalation anesthetics (halothane, sevoflurane) may weaken the uterotonic response while worsening hypotension. These interactions are manageable but require awareness during cesarean and complicated vaginal deliveries. Carbetocin is contraindicated in pregnancy and labor before delivery of the infant. It must never be used for labor induction or augmentation. Significant hepatic or renal impairment reduces clearance and extends the already-prolonged pharmacological effect. Bottom line on safety: carbetocin has a clean profile for its intended single-dose postpartum use. The risks are real but transient and manageable in a monitored obstetric setting. The drug earns its safety grade through the CHAMPION trial's massive dataset and years of post-marketing surveillance across 40+ countries.
Verify Carbetocin (Duratocin/Pabal) dosing and safety with a second opinion
Hospital-formulary licensed pharmaceutical administered under direct obstetric supervision. EU brand: Pabal (Ferring Pharmaceuticals). Canada: Duratocin (Ferring). Heat-stable formulation is WHO-qualified (EML 2019). Ferring–Medicines Patent Pool license (April 2024) enables licensed generic production for LMIC markets. No compounded, gray-market, or consumer supply chain exists.
| Test | When | Target |
|---|---|---|
| Maternal blood pressure and heart rate | Every 15 minutes for at least 1 hour post-dose | BP >90/60 mmHg; HR <100 bpm |
| Uterine tone (fundal palpation and height assessment) | Every 15–30 minutes post-delivery | Firm, well-contracted uterus at or below umbilical level within 1 hour of delivery |
| Quantitative blood loss estimation | Continuous peripartum and for at least 2 hours post-delivery | <500 mL for vaginal delivery; <1,000 mL for cesarean section |
| Hypersensitivity / anaphylaxis surveillance | First 30 minutes post-dose; anaphylaxis resuscitation equipment must be immediately available | No urticaria, bronchospasm, angioedema, or hemodynamic collapse |
Transient hypotension and tachycardia are common ADRs (1–10% per Pabal SmPC), particularly after IV administration
Confirm adequate uterotonic response; identify persistent uterine atony requiring escalation to additional uterotonics
Primary endpoint of PPH prevention; defines threshold for escalation therapy (≥500 mL or hemodynamic compromise)
Rare but serious allergic/hypersensitivity reactions reported with carbetocin (Pabal SmPC Section 4.4)
Onset of uterotonic activity with initial uterine contraction following IV administration
Peak uterotonic effect with sustained rhythmic uterine contractions; peak plasma concentration reached (IM)
Continued uterine contractile activity; plasma levels declining but pharmacological effect maintained
Uterotonic effect waning; uterine tone stabilized in most patients; drug largely eliminated
0 to 2 minutes: The uterotonic effect kicks in fast after IV injection. Initial contraction begins within two minutes. IM onset runs slower, with peak plasma levels not arriving until around 30 minutes. Flushing, warmth, and headache are common at this stage, especially with the IV route. 2 to 30 minutes: Peak contractile activity. The uterus settles into sustained rhythmic contractions. IM recipients hit peak plasma concentration around the 30-minute mark. Transient tachycardia, hypotension, nausea, abdominal pain, and metallic taste may appear in 1 to 10 percent of patients. These effects are brief. 30 to 60 minutes: Plasma levels are falling, but the uterotonic effect holds. The reason is pharmacological, not pharmacokinetic. The OXTR has internalized and keeps signaling from inside the cell. IV half-life is about 33 minutes; IM half-life about 55 minutes. Side effects are generally fading. Abdominal cramping may linger. 1 to 2 hours: The drug is mostly cleared. Uterine tone has stabilized in most patients. The OXTR stays internalized, so the contractile response doesn't snap back abruptly. If the uterus is still boggy at this point, carbetocin's window is closed. Time to escalate to a different agent.
Onset within 2 min of IV administration; initial uterine contraction begins. IM onset is slower: peak plasma concentration reached at ~30 min.
N/A: hospital setting only
Sustained rhythmic uterine contractions. IM peak plasma concentration at ~30 min. Maximum contractile activity. IV plasma levels declining but OXTR-mediated signaling sustained via endosomal compartments.
N/A
Continued uterine contractile activity as plasma levels decline. Pharmacological effect maintained via sustained intracellular signaling from internalized OXTR (endosomal pathway). IV t½ ~33 min; IM t½ ~55 min.
N/A
Uterotonic effect waning; uterine tone stabilized. Drug largely eliminated. OXTR remains internalized: receptor does not rapidly recycle; uterine response does not abruptly return.
N/A
Source: Pabal SmPC (UK EMC): geometric mean terminal half-life: 33 min IV, 55 min IM
Loading the interactive decay curve.
Carbetocin is approved in over 40 countries for prevention of postpartum hemorrhage. In Europe, it's marketed as Pabal (Ferring Pharmaceuticals). In Canada, it's sold as Duratocin. Australia, Singapore, and multiple countries in Latin America, Asia, and Africa have granted approval. The FDA has not approved carbetocin. In the United States, it is classified as a research compound. No US compounding pharmacies produce it, and off-label procurement is not appropriate for clinical use. WHO added the heat-stable formulation to its Model List of Essential Medicines in 2019. In April 2024, Ferring signed a Medicines Patent Pool license enabling generic production for low- and middle-income country markets. Carbetocin is not on the WADA prohibited list. It has no performance-improving applications. This content is for informational purposes only. Carbetocin is a hospital-administered pharmaceutical that requires qualified obstetric supervision. It is not intended for self-administration. Always follow institutional protocols and the applicable product monograph (Pabal SmPC or Duratocin Product Monograph) for prescribing information.
Peptide Schedule Research TeamReviewed Apr 20269 Citations
