Analgesic effect of medicinal leeches in chronic diseases
Aminov R (2025) · Annals of Parasitology · n=48
Study Profile
- Design
- single-center prospective observational cohort study of Hirudo verbana applied to patients of varied age and sex with chronic pain across multiple body systems (Cellular and Organism Biotechnology Laboratory, Zaporizhzhia National University, Ukraine)
- Sample size (n)
- 48
- Intervention
- Repeated Hirudo verbana applications across multiple sessions; analgesic onset and time course tracked along with subjective energy and selected blood physiological parameters
- Comparator
- No randomized comparator - within-subject pre/post analgesia assessment
- Primary endpoint
- Onset and maximum magnitude of pain-relieving effect across consecutive leech applications; subjective vitality reports; recovery of selected physiological blood parameters and organ function indices
- Primary result
- Analgesic effect appeared after the first leech attachment, with maximum effect emerging after the third and fourth productions; pain relief was robust regardless of sex or age; majority of subjects reported strong influx of energy and gradual recovery of physiological blood parameters after completing the course; no severe adverse events reported in this small Ukrainian cohort
- Follow-up duration
- course of multiple weekly leech applications (typical 4-session protocol)
- PMID
- 40682863
Key Findings
- Analgesic effect appeared after the first leech attachment and peaked after the third and fourth sessions — supports the multi-session standard protocol used in European OA RCTs
- Pain relief observed regardless of patient sex or age
- Patient-reported energy increase and recovery of selected physiological blood parameters after the full course
- Uses Hirudo verbana rather than Hirudo medicinalis - adds species diversity to the analgesia evidence base
- Documents post-Soviet/Ukrainian cohort of hirudotherapy, complementing Aminov and other Eastern European publications
Limitations
- Observational cohort with no randomized comparator - cannot separate biological from expectancy/placebo effects
- Small sample (n=48) and heterogeneous chronic pathologies limit interpretability
- Patient-reported analgesia without validated pain measurement instruments (no VAS or BPI reported)
- Single-center Ukrainian setting - generalizability untested
- No standardized adverse-event reporting protocol described in abstract
Clinical Implications
Aminov 2025 provides a small contemporary Ukrainian cohort showing the time course of cumulative leech analgesia across diverse chronic pain conditions. The observation that the analgesic effect builds across 3-4 sessions is consistent with the broader European leech-therapy literature and supports the standard multi-session protocol. The trial is hypothesis-generating only; the lack of validated pain scales, randomization, and blinded comparator limits its placement in the broader pain-medicine hierarchy. For US clinicians, this study adds context for understanding why multi-session protocols are common in European hirudotherapy practice, but does not establish efficacy for any specific indication.
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