American Society of Hirudotherapy

Pharmacology

From leech biology to three FDA-approved pharmaceuticals

Last Updated: May 27, 2026Reviewed by: Andrei Dokukin, MD
9 FDA-approved drugs derived from leech compounds192+ preclinical compounds

Drug-vs-leech distinction

FDA-approved drug

Bivalirudin, dabigatran, lepirudin & derivatives

Approval:
FDA-approved drugs (NDA/BLA pathways)
Indication:
PCI anticoagulation, atrial fibrillation, HIT, VTE
Derived from:
Hirudin and salivary compounds of Hirudo medicinalis
FDA-cleared medical device

Hirudo medicinalis / Hirudo verbana

FDA status:
FDA-cleared medical device (K040187, June 2004)
Cleared indication:
Venous congestion in surgical flaps and replanted tissue

These are two distinct regulatory contexts. The drug above is a recombinant or synthetic pharmaceutical analog regulated under FDA NDA/BLA pathways. The whole-leech therapy is regulated as a medical device. Clinical claims for the drug do NOT extend to whole-leech therapy, and vice versa.

201 compounds catalogued in ASH Compound Reference

Each compound page distinguishes whole-leech therapy from purified / recombinant / synthetic-analog pharmaceutical derivatives, with explicit clinical-translation-limit statements preventing mechanism-to-claim leakage.

→ Full Compound Reference→ Bivalirudin (FDA-approved synthetic analog)→ Hirudin (natural leech-derived)

Medicinal leech biology has directly inspired three FDA-approved direct thrombin inhibitors and contributed to the conceptual development of oral anticoagulants used by millions of patients worldwide (bivalirudin alone is used in over 1 million PCI procedures annually; Stone et al., N Engl J Med, 2008; PMID: 18832246). The leech accounts for half of all zoopharmaceutical FDA approvals.

Important Distinction

FDA-cleared leech-derived drugs (bivalirudin, lepirudin, desirudin, dabigatran) are separate pharmaceutical products — not leech therapy. These pages document the translational pipeline from zoopharmaceutical biology to clinical medicine.

The Translational Pipeline

Leech SGS→Native Hirudin→Recombinant Hirudin→Bivalirudin (FDA 2000)→Dabigatran (FDA 2010)

Topics

FDA-Approved

Direct Thrombin Inhibitors

The DTI drug class: from native hirudin to bivalirudin and dabigatran — a four-decade journey.

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FDA-Approved

Bivalirudin

Class I, Level B-R recommendation for STEMI PCI (2025 ACC/AHA). HORIZONS-AMI: 43% reduction in cardiac mortality. peak revenue ~$636M (2014, pre-generic; The Medicines Company / Angiomax); global market ~$666M (2025, post-generic).

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FDA-Approved

Oral Anticoagulants

Dabigatran and the DOAC revolution — conceptual lineage from leech hirudin crystallography.

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Investigational

Leech Extracts

Piyavit and whole-extract formulations: international pharmacology, not FDA-cleared.

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Preclinical

Drug Pipeline

Destabilase, decorsin, saratin, eglin C — next-generation candidates from the leech secretome.

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Reference

Laboratory Effects

APTT, INR, platelet monitoring, and laboratory parameter changes during hirudotherapy.

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By the Numbers

3

FDA-Approved DTIs

$636M

Peak Bivalirudin Revenue

200+

Bioactive Proteins

99%+

Unexploited as Drug Leads

Related Resources

Bioactive Science

The molecular pharmacology of the leech salivary system.

Hemostasis & Coagulation

The complete anticoagulant cascade targeted by leech compounds.

Drug Pipeline

Next-generation candidates from the leech secretome.

This website provides educational information and does not constitute medical advice, diagnosis, or treatment recommendations. Medicinal leech therapy carries clinically meaningful risks and should be performed only by qualified clinicians under institutionally approved protocols. FDA 510(k) clearance for medicinal leeches is limited to specific indications; investigational and off-label discussions are labeled accordingly. For patient-specific guidance, consult a qualified healthcare provider.

Pharmacology — From Leech Biology to FDA-Approved Drugs | ASH