Isoprinosine (Inosine Pranobex)

Isoprinosine is used as an antiviral and immunostimulant in several viral and immunodeficiency conditions.

• Herpes simplex virus infections: helps reduce lesion duration and viral shedding.
• Influenza and other acute viral infections: supports faster symptom resolution and immune clearance.
• Subacute sclerosing panencephalitis: used as adjunct therapy to modulate immune response.
• Immunostimulation in immunodeficient patients: enhances cellular immunity to reduce infection risk.

• Inosine Pranobex modulates the immune system by stimulating T‑lymphocyte proliferation and natural killer cell activity, and by increasing production of cytokines such as interleukin‑2 and interferon‑γ. The compound also interferes with viral replication by enhancing host antiviral defenses, leading to improved clearance of infected cells. It up‑regulates major histocompatibility complex expression, facilitating antigen presentation and further activation of adaptive immunity.

Isoprinosine may cause adverse reactions, which are categorized by frequency and severity, and should be monitored during therapy.

Common Side Effects

• Nausea: mild stomach upset that may improve with food and usually resolves without intervention.
• Headache: transient mild to moderate headache, often responsive to simple analgesics.
• Fatigue: feeling of tiredness or reduced energy that may lessen with rest.
• Rash: mild skin erythema or itching, typically limited to small areas and not progressive.

Serious or Rare Side Effects

• Severe allergic reaction: swelling of face or throat, breathing difficulty, or hives, requiring immediate medical attention.
• Hepatic dysfunction: elevated liver enzymes, jaundice, or hepatitis‑like symptoms, warranting laboratory monitoring.
• Hematologic abnormalities: significant reductions in white blood cells or platelets, increasing infection or bleeding risk.

Before prescribing Isoprinosine, clinicians should consider several precautionary measures.

• Pregnancy: safety category is unknown; use only if potential benefit justifies the risk.
• Breastfeeding: insufficient data; advise caution and monitor infant for adverse effects.
• Renal impairment: dose adjustment may be required in severe renal dysfunction.
• Hepatic disease: monitor liver enzymes regularly during treatment.
• Immunocompromised patients: use under specialist supervision due to altered immune response.
• Store at ambient temperature below 25°C: keep in original container, protect from moisture and direct sunlight.

Isoprinosine can interact with other medicines, influencing its efficacy or safety.

Major Interactions (Avoid)

• Immunosuppressive agents: may counteract immunostimulatory effect.
• Live attenuated vaccines: increased risk of vaccine‑derived infection.
• Anticoagulants (warfarin): potential enhancement of bleeding risk.

Moderate Interactions (Monitor Closely)

• Corticosteroids: may diminish therapeutic benefit.
• Antiretroviral drugs: possible pharmacokinetic interactions affecting plasma levels.
• Hepatotoxic drugs: combined use may increase liver enzyme elevations.