Hidrosmin

Bioflavonoid, «venoactive» agent

ATC code: C05CA05 (Hidrosmin)

Mechanism of action

A semisynthetic bioflavonoid – hydroxyethylated diosmin. Claimed in vitro effects: raised venous tone via adrenergic receptors, reduced capillary permeability, and anti-inflammatory action on the endothelium. Mechanism data in humans are sparse; oral bioavailability is low. No evidence base exists for hard clinical outcomes (ulcer healing, disease progression).

Indications

Chronic venous insufficiency

Adjunct

Used symptomatically for leg heaviness, edema, and pain in chronic venous insufficiency CEAP classes C0s–C3. Evidence is weak: Spanish trials from the 1990s showed modest symptom and calf-circumference reduction, but no independent large RCTs or meta-analyses exist. The 2020 Cochrane review of flavonoids overall noted modest effects on pain and edema with very low certainty. Foundation therapy is compression and lifestyle change; hidrosmin does not replace them and does not affect disease progression. The ESVS 2022 international guideline does not mention this drug.

Sources

Practical notes

Evidence

Evidence for hidrosmin and other «venotonics» (diosmin, troxerutin, rutosides) rests on small trials, mostly from Spain, France, and Eastern Europe. No effect has been described on clinically meaningful outcomes (venous-ulcer healing, thrombosis rates, disease progression). Use is justified only as a short-term symptomatic add-on to compression and lifestyle change; do not expect disease modification.

Common myths

Myth: «venotonics strengthen vessels and prevent varicose veins.» Fact: no flavonoid agent has proven effect on varicose-vein formation or progression of venous disease. Foundation prevention: physical activity, weight control, avoiding prolonged standing or sitting, and graduated compression once symptoms appear. Myth: «hidrosmin is the answer to leg swelling.» Fact: leg edema requires ruling out cardiac, renal, hepatic, and thyroid causes before attributing it to venous disease.

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Official sources

Direct links to regulator labels. Open in a new tab.

AEMPS / CIMA

Spanish Medicines Information Centre (CIMA)

Label dated: 02/19/2025

Safety

Contraindications

Hypersensitivity to hidrosmin or flavonoids
Pregnancy and breastfeeding (limited data)

Serious adverse effects

Serious allergic reactions (rare)

Common adverse effects

Nausea
Epigastric pain
Headache
Skin rash (rare)

PregnancyFDA C

Safety not established. Not recommended in pregnancy – class 2 graduated compression stockings are first-line for pregnancy venous symptoms.

Breastfeeding

No data. Not used during lactation.

Calculate RID

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

Frequently asked

What is Hidrosmin used for?

Hidrosmin is evaluated for the following indications with varying evidence strength: Chronic venous insufficiency (evidence tier D). See the full indication matrix with dosing and citations above on this page.

What are the side effects of Hidrosmin?

Common side effects of Hidrosmin (≥ 1 in 100): Nausea, Epigastric pain, Headache, Skin rash (rare). See the Safety section for uncommon and serious reactions.

Is Hidrosmin safe during pregnancy?

FDA category C. Safety not established. Not recommended in pregnancy – class 2 graduated compression stockings are first-line for pregnancy venous symptoms.

Is Hidrosmin compatible with breastfeeding?

No data. Not used during lactation.

Who should not take Hidrosmin?

Hidrosmin is contraindicated in: Hypersensitivity to hidrosmin or flavonoids; Pregnancy and breastfeeding (limited data). Full list in the Safety section.