What are the side effects of the drug arbitol? (Umifenovir)

October 12, 2025 •

3 min read

Umifenovir, a broad-spectrum antiviral sold under the brand name Arbidol in Russia and China, is reported to have a generally favorable safety profile based on clinical experience. However, as with any medication, understanding what are the side effects of the drug arbitol (umifenovir) is crucial for safe and effective use. While the drug is not approved in the United States, its use for influenza and other respiratory infections is widespread in specific regions.

Quick Summary

Umifenovir (Arbidol) side effects are typically mild and may include digestive issues like nausea or diarrhea. While generally well-tolerated, some individuals may experience fatigue or allergic reactions. It is used to treat influenza and other respiratory infections, primarily in Russia and China.

Key Points

Name Clarity: 'Arbitol' is likely a misspelling of umifenovir, which is sold under the brand name Arbidol in Russia and China for treating respiratory infections.
Common Effects: The most frequent side effects of umifenovir are mild gastrointestinal issues, such as nausea, diarrhea, and vomiting.
Infrequent Effects: Less common adverse reactions can include fatigue, weakness, headaches, and transient increases in liver enzymes.
Serious Reactions: While rare, severe allergic reactions to umifenovir have been reported, requiring immediate medical attention.
Drug Interactions: Umifenovir is metabolized by the CYP3A4 enzyme, so it can interact with other drugs, including antifungals, antibiotics, and some HIV medications.
Contraindications: The medication should be used with caution in elderly patients and individuals with liver or kidney problems.
Safety Profile: Clinical experience and studies show that umifenovir is generally well-tolerated and safe, particularly with short-term use.

The drug name 'arbitol' is a common misspelling of umifenovir, which is more famously known by its brand name, Arbidol. This antiviral drug has been licensed and used for decades in Russia and China for treating and preventing influenza and other respiratory viral infections. The side effect profile for umifenovir is considered relatively mild, though patients should be aware of all potential adverse reactions.

Common Side Effects of Umifenovir

Based on clinical data and reported experiences, the most frequent side effects associated with umifenovir are generally mild and transient. These include:

Gastrointestinal Distress: The most commonly reported issues involve the digestive system. Patients may experience nausea, diarrhea, vomiting, or abdominal pain.
Allergic Reactions: Some individuals may experience hypersensitivity reactions, which can manifest as hives, skin rashes, or itching. While rare, more severe allergic reactions are possible and require immediate medical attention.
Fatigue and Weakness: Feelings of unusual tiredness or general weakness have been documented in some patients taking umifenovir.
Headache: Mild headaches are another potential side effect that has been reported.

Less Common Side Effects

Beyond the most frequent adverse reactions, a smaller subset of patients may experience other symptoms, such as:

Liver Enzyme Abnormalities: Some reports have noted transient increases in liver enzymes (transaminases), though severe impairment of liver function is not typically observed.
Kidney Function: No severe impairment of kidney function has been consistently noted in studies, but monitoring is still advised in vulnerable populations.
Neurological Effects: Though less common, neurological or psychiatric symptoms like anxiety or acute confusion have been documented in some clinical study settings, particularly when the drug is used in combination with others.

Contraindications and Precautions

Certain patient populations should use umifenovir with caution or avoid it entirely due to a higher risk of adverse effects.

Children and Elderly: Safety and efficacy have not been firmly established in young children (under 2 years old), while older patients may be more susceptible to side effects.
Liver or Kidney Conditions: Individuals with impaired liver or renal function may require dosage adjustments and should be closely monitored by a healthcare provider.
Hypersensitivity: The drug is contraindicated in patients with a known hypersensitivity to umifenovir or any of its components.

Drug Interactions

Umifenovir's metabolism involves the cytochrome P450 enzyme system, specifically CYP3A4, which can lead to various drug-drug interactions. It is crucial to inform a healthcare provider of all medications, supplements, and herbal products being taken to avoid potential issues.

Drugs that increase umifenovir levels: Certain medications that inhibit CYP3A4, such as some antifungals, antibiotics, and HIV drugs (e.g., ketoconazole, clarithromycin, ritonavir), can increase the concentration of umifenovir in the blood, potentially elevating the risk of side effects.
Drugs that decrease umifenovir levels: On the other hand, CYP3A4 inducers like rifampin or certain anticonvulsants can decrease umifenovir concentrations, potentially reducing its effectiveness.

Comparison: Umifenovir (Arbidol) vs. Abitol (Cyproheptadine)

Confusion between umifenovir and other medications is common. The generic name of the antihistamine Abitol is cyproheptadine, and it has a very different side effect profile from umifenovir.


Feature	Umifenovir (Arbidol)	Abitol (Cyproheptadine)
Drug Class	Antiviral, immune modulator	Antihistamine
Primary Use	Prophylaxis and treatment of influenza and other respiratory infections	Management of allergic conditions and appetite stimulation
Common Side Effects	Gastrointestinal issues (nausea, diarrhea), fatigue	Drowsiness, dizziness, dry mouth, weight gain
Severe Side Effects	Rare severe allergic reactions	Mood changes, seizures, irregular heartbeat (rare)
Primary Market	Russia and China	Global market (brand names vary)

Conclusion

Umifenovir (Arbidol) has a generally favorable safety profile, with side effects that are often mild and primarily affect the gastrointestinal system. However, patients should be vigilant for any unusual symptoms and seek medical advice, particularly if combining umifenovir with other medications. The confusion with the name 'arbitol' highlights the importance of clarifying drug names with healthcare professionals to ensure the correct medication and side effect information is discussed. Individuals with underlying health conditions, especially liver or kidney issues, should proceed with caution and under strict medical supervision. A comprehensive discussion with a doctor or pharmacist is the best way to understand the full spectrum of potential risks and benefits.

For more detailed information, studies, and mechanism of action, refer to the extensive research published on umifenovir, sometimes referred to as Arbidol.

Frequently Asked Questions

The term 'arbitol' is a common misspelling. The correct drug name is Arbidol, which is the brand name for the antiviral medication umifenovir. Umifenovir is used to treat and prevent influenza and other respiratory viral infections.

The most common side effects of umifenovir are mild and typically involve the digestive system. These can include nausea, vomiting, diarrhea, and abdominal pain.

Serious side effects from umifenovir are rare, but allergic reactions such as skin rashes or hives can occur. If any severe symptoms are experienced, such as difficulty breathing or swelling, immediate medical help should be sought.

Umifenovir's side effect profile is generally considered mild and is often compared favorably to some other antiviral drugs that may have more serious side effects. Comparison studies, however, have had varied results.

People with known hypersensitivity to the drug should avoid it. Caution is also advised for young children and elderly patients, especially those with pre-existing liver or kidney conditions, who may be more susceptible to side effects.

Umifenovir is not typically known for causing the level of drowsiness seen with some antihistamines, like the one sometimes confused with it (Abitol). Any feelings of fatigue or weakness are generally mild.

Because umifenovir is metabolized by the CYP3A4 enzyme, it has the potential for drug-drug interactions. Its effectiveness or the risk of adverse effects could be altered if combined with certain medications. Always inform a healthcare provider of all current medications to avoid harmful interactions.