Diosmin, a flavonoid compound used to treat vascular disorders, was first isolated in the 1930s and later developed for medical use in the 20th century. Its history is marked by its effectiveness in improving venous tone, reducing capillary permeability, and treating chronic venous insufficiency and hemorrhoidal disease. Diosmin is commonly administered in combination with hesperidin, and its development featured studies on safety, efficacy, and dosage optimization. While generally well-tolerated, diosmin’s use is guided by careful clinical evaluation, particularly in patients with known hypersensitivity to flavonoids. Its inclusion in multiple vascular therapy regimens reflects its role in managing circulation-related conditions.
BRAND NAMES
Daflon® – the most widely known pharmaceutical preparation of diosmin, often combined with hesperidin.
Venusmin® – used in some countries for chronic venous insufficiency.
Diovenor® – another diosmin/hesperidin combination for venous disorders.
MECHANISM OF ACTION
Diosmin exerts its therapeutic effects primarily through venotonic, anti-inflammatory, and capillary-protective actions. It enhances the tone and contractility of venous walls, improving venous return and reducing pooling of blood in the lower limbs. Simultaneously, diosmin inhibits the release of inflammatory mediators such as prostaglandins and leukotrienes, decreasing vascular inflammation.
PHARMACOKINETICS
Absorption
Diosmin is poorly soluble in water, and when administered orally, it is rapidly metabolized in the intestine by intestinal microflora to its aglycone form, diosmetin, which is the active metabolite. After conversion, diosmetin is readily absorbed from the gastrointestinal tract, with peak plasma concentrations typically occurring within 1–2 hours after oral intake. Food can slightly delay absorption, but does not significantly affect overall bioavailability.
Distribution
The estimated Vd ranges from 0.7 to 1.0 L/kg, indicating distribution beyond the blood plasma but limited penetration into deep tissues.
Metabolism
Diosmin is extensively metabolized in the body after oral administration. In the gastrointestinal tract, it is first hydrolyzed by intestinal microflora to its active aglycone, diosmetin, which is then absorbed into the bloodstream. Once absorbed, diosmetin undergoes phase II metabolism in the liver, primarily methylation, sulfation, and glucuronidation, forming water-soluble metabolites that can be readily excreted.
Elimination
Diosmin and its active metabolite diosmetin are primarily eliminated via the urine and feces in the form of conjugated metabolites, mainly glucuronides and sulfates. After oral administration, approximately 80–90% of the administered dose is excreted within 24 hours, with urinary excretion being the dominant route.
PHARMACODYNAMICS
Diosmin exerts its pharmacodynamic effects primarily through venotonic, anti-inflammatory, and capillary-protective mechanisms. It enhances venous tone and contractility, improving venous return and reducing blood pooling in the lower limbs. Diosmin also inhibits the release of inflammatory mediators such as prostaglandins and leukotrienes, thereby decreasing vascular inflammation and edema. Additionally, it strengthens capillary walls, reduces permeability, and supports lymphatic drainage, which helps alleviate swelling and tissue congestion.
ADMINISTRATION
Diosmin is administered orally, usually in the form of tablets or coated pills, often combined with hesperidin in pharmaceutical formulations. The recommended dose for adults typically ranges from 500–1000 mg once or twice daily, depending on the condition being treated. For chronic venous insufficiency, treatment is generally long-term, while for acute hemorrhoidal attacks, higher doses may be used for a short period.
DOSAGE AND STRENGTH
Diosmin is typically administered orally in 500 mg or 1000 mg tablets, often in combination with hesperidin in a 9:1 ratio. For chronic venous insufficiency and varicose veins, the usual adult dose is 500 mg twice daily or 1000 mg once daily, with treatment often continuing long-term depending on symptom severity.
DRUG INTERACTIONS
Diosmin has a low potential for drug interactions due to its limited metabolism and primary conversion to diosmetin by intestinal microflora. It is not known to significantly inhibit or induce cytochrome P450 enzymes, minimizing interactions with most commonly prescribed medications.
FOOD INTERACTIONS
Diosmin can be taken with or without food, and food does not significantly affect its overall absorption or therapeutic efficacy. Taking diosmin with meals may improve gastrointestinal tolerance, reducing the risk of mild stomach discomfort. There are no specific dietary restrictions, and it does not appear to interact adversely with common foods or beverages.
CONTRAINDICATIONS
Diosmin is contraindicated in individuals with known hypersensitivity to diosmin, hesperidin, or any component of the formulation. It should not be used in patients with severe allergic reactions to citrus flavonoids. Caution is advised in pregnant or breastfeeding women, as safety data are limited, and diosmin should only be used if the potential benefits outweigh the risks.
SIDE EFFECTS
Mild abdominal pain
Nausea
Diarrhea
Indigestion
Headache
Dizziness (rare)
Skin rash
Itching.
OVER DOSAGE
There is limited clinical experience with diosmin overdose, and it is generally considered to have a wide safety margin. In cases of excessive intake, patients may experience gastrointestinal discomfort such as nausea, vomiting, abdominal pain, or diarrhea. Other mild symptoms may include headache or dizziness.
TOXICITY
Diosmin has a low toxicity profile and is generally considered safe even at doses higher than therapeutic levels. Preclinical studies indicate a high median lethal dose (LD50) in animals, suggesting minimal risk of acute toxicity. Chronic toxicity studies have shown that long-term administration at therapeutic doses does not produce significant organ damage or biochemical abnormalities.
