[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Pulmonary arterial hypertension drugs (endothelin receptor antagonists and prostacyclins)](https://durgical.com/en/pharmacology/classes/pulmonary-arterial-hypertension-drugs/) › Sotatercept

# Sotatercept

## Pulmonary arterial hypertension drugs (endothelin receptor antagonists and prostacyclins)?

Pulmonary arterial hypertension drugs (endothelin receptor antagonists and prostacyclins)

## Pregnancy: avoid?

Avoided in pregnancy: a pregnancy test is done first and effective contraception is used during treatment and for months after the last dose; breastfeeding is avoided.

An injected activin-signalling inhibitor for pulmonary arterial hypertension. It traps growth factors that drive vessel remodelling; it raises haemoglobin.

Updated Nov 12, 2026

## Quick facts

**Group**
[Pulmonary arterial hypertension drugs (endothelin receptor antagonists and prostacyclins)](https://durgical.com/en/pharmacology/classes/pulmonary-arterial-hypertension-drugs/)

**Target**
Activin A and related ligands (GDF8, GDF11), trapped by an ActRIIA–Fc fusion protein

**Used for**
Pulmonary arterial hypertension

**Key effects**
Headache · Nosebleeds · Spider veins

**Monitor**
Bleeding signs · Pregnancy test before starting

**ATC**
C02KX06

No doses: the clinician sets them by the current guideline.

On this page

- The basics Mechanism of action
- Indications
- Adverse effects
- Pharmacokinetics
- Memory aid

- Clinical What the labels mean

- Safety Contraindications
- Key interactions
- What is monitored
- Administration and safety
- Pregnancy and breastfeeding
- Nursing care

- Study Test yourself

- Connections Connections

## Mechanism of action

Sotatercept is a fusion protein made of the extracellular domain of the activin receptor type IIA joined to an antibody Fc fragment. It acts as a 'ligand trap', binding activin A, GDF8 and GDF11 before they reach their receptors. In pulmonary arterial hypertension, too much activin signalling (SMAD2/3) and too little BMPR2 signalling (SMAD1/5/8) drive cell growth in small pulmonary arteries; trapping the ligands rebalances these pathways and can reverse vessel remodelling rather than only dilating vessels. Trapping the same ligands also stimulates red-cell production.

- ActRIIA–Fc fusion traps activin A, GDF8, GDF11
- Less SMAD2/3 pro-proliferative signalling
- Balance with BMPR2 signalling is restored
- Pulmonary arterial remodelling regresses

## Indications

- Pulmonary arterial hypertension in adults, added to background therapy, to improve exercise capacity and delay worsening [Pulmonary hypertension and cor pulmonale →](https://durgical.com/en/conditions/pulmonary-hypertension-and-cor-pulmonale/)

## Adverse effects

### Common

- Headache, dizziness
- Nosebleeds
- Spider veins (telangiectasia)
- Rash or skin redness, easy bruising
- Diarrhoea

### Serious (rare, important)

- Raised haemoglobin (erythrocytosis)
- Low platelet count (thrombocytopenia)
- Serious bleeding (gut, urine, lungs, heavy periods)

## Contraindications

- Hypersensitivity to sotatercept
- Doses are delayed when haemoglobin is too high or platelets are too low

## Key interactions

**Anticoagulants and antiplatelets**
More risk of bleeding when platelets fall.

## What is monitored

- Haemoglobin and platelet count before doses, especially early
- Bleeding signs; telangiectasia
- Pregnancy test before starting
- Exercise capacity and PAH symptoms

## Administration and safety

- Subcutaneous injection every three weeks; patients or carers are trained to prepare and inject it at home.
- Blood tests decide whether each dose is given, delayed or changed.
- It is added to, not a replacement for, existing PAH medicines.

## Pregnancy and breastfeeding

Avoided in pregnancy: a pregnancy test is done first and effective contraception is used during treatment and for months after the last dose; breastfeeding is avoided.

## Nursing care

- Before each dose early in treatment: check haemoglobin and platelets as ordered.
- Teach to report nosebleeds, blood in urine or stools, coughing blood or heavy periods.
- Confirm a negative pregnancy test and effective contraception.
- Teach injection technique and safe sharps disposal.

## Pharmacokinetics

**Absorption**
Subcutaneous injection every three weeks.

## Memory aid

SOTATERCEPT 'interCEPTS' activin: a trap (-cept) that stops the vessel wall from thickening, and thickens the blood a little.

## Test yourself

Think of the answer, then tap the question to see it.

## What kind of molecule is sotatercept?

A fusion protein of the activin receptor IIA extracellular domain with an Fc fragment, acting as a ligand trap.

## How does sotatercept differ from classic PAH vasodilators?

It targets the growth signalling that remodels pulmonary arteries (activin/BMPR2 balance) instead of only dilating them.

## Which two blood values are checked before doses?

Haemoglobin (it can rise) and platelets (they can fall).

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/sotatercept/)

[More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology)

## What the labels mean

**Pregnancy: avoid**
Avoided in pregnancy: a pregnancy test is done first and effective contraception is used during treatment and for months after the last dose; breastfeeding is avoided.

## Connections

## Related drugs 4

- [Bosentan](https://durgical.com/en/pharmacology/bosentan/)
- [Epoprostenol](https://durgical.com/en/pharmacology/epoprostenol/)
- [Sildenafil](https://durgical.com/en/pharmacology/sildenafil/)
- [Luspatercept](https://durgical.com/en/pharmacology/luspatercept/)

## Related conditions 1

- [Pulmonary hypertension and cor pulmonale](https://durgical.com/en/conditions/pulmonary-hypertension-and-cor-pulmonale/)

[← Back to the class: Pulmonary arterial hypertension drugs (endothelin receptor antagonists and prostacyclins)](https://durgical.com/en/pharmacology/classes/pulmonary-arterial-hypertension-drugs/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [Sotatercept-csrk Injection: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a624053.html) (MedlinePlus (U.S. National Library of Medicine), 2024); [Sotatercept: A novel therapeutic approach for pulmonary arterial hypertension through transforming growth factor-β signaling modulation](https://pmc.ncbi.nlm.nih.gov/articles/PMC11948201/) (World Journal of Methodology, via PubMed Central, 2025); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=C02KX06) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.

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License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/sotatercept/