What Can You Not Take With Valacyclovir? A Guide to Drug Interactions

According to reports in the FDA Adverse Event Reporting System (FAERS), valacyclovir-induced acute kidney injury is a known, though rare, side effect. When taking the antiviral medication valacyclovir, it is critical to understand what can you not take with valacyclovir to avoid increased toxicity, especially concerning kidney function.

Quick Summary

Combining valacyclovir with certain medications, such as NSAIDs, immunosuppressants, and other antivirals, can increase the risk of serious side effects, primarily affecting kidney function. Avoiding or managing these interactions under medical supervision is crucial for safe treatment.

Key Points

• Nephrotoxic Drugs: Avoid combining valacyclovir with medications known to harm the kidneys, such as NSAIDs (ibuprofen, naproxen) and immunosuppressants (cyclosp­orine, tacrolimus), due to increased risk of kidney damage.

• Alcohol: Use caution with alcohol, as it can worsen common valacyclovir side effects like dizziness and nausea, and excessive drinking can strain the liver and kidneys.

• Antiviral Overlap: Do not take valacyclovir with other antivirals like acyclovir, famciclovir, or ganciclovir to prevent an overdose of the active antiviral compound.

• Renal Clearance Inhibitors: Medications such as probenecid and cimetidine can interfere with valacyclovir's elimination, leading to higher levels in the body and increased side effects.

• Live Vaccines: Inform your doctor about valacyclovir use before receiving live vaccines, as the antiviral may reduce their effectiveness.

• Hydration is Key: To protect your kidneys while on valacyclovir, maintain adequate hydration, especially if you are also taking other potentially nephrotoxic drugs.

• Full Disclosure: Always provide your doctor with a complete list of all medications and supplements you are taking to ensure a safe treatment plan.

Valacyclovir (Valtrex) is an antiviral used to treat herpes simplex and varicella-zoster virus infections. Since valacyclovir is converted to acyclovir and primarily eliminated by the kidneys, combining it with medications that affect kidney function or clearance can lead to higher drug levels and increased toxicity risks.

Protecting Your Kidneys from Drug Interactions

Combining valacyclovir with nephrotoxic drugs increases the risk of acute kidney injury (AKI), particularly in older or dehydrated individuals. Staying well-hydrated is important during treatment. Always inform your doctor about all medications you are taking.

Medications That Affect Kidney Function

Certain medications should be avoided or used cautiously with valacyclovir due to increased kidney strain:

• NSAIDs: Pain relievers like ibuprofen and naproxen can increase the risk of kidney damage when used with valacyclovir. Studies show a higher risk of AKI with concurrent use of valacyclovir and some NSAIDs.
• Immunosuppressants: Drugs such as cyclosporine, tacrolimus, and methotrexate, used in conditions like organ transplants, can be nephrotoxic and increase risk when combined with valacyclovir, especially in those with existing kidney problems. Mycophenolate mofetil can also increase neutropenia risk.
• Aminoglycoside Antibiotics: Aminoglycoside antibiotics like gentamicin, amikacin, and tobramycin can affect kidney function and increase risk when combined with valacyclovir.
• Other Potential Interactions: Other medications that may interact with valacyclovir include chemotherapy drugs like cisplatin and axitinib, and lithium. Additionally, drugs like cimetidine and probenecid can interfere with valacyclovir's clearance by the kidneys. Other antivirals, such as acyclovir, famciclovir, or valganciclovir, should not be taken with valacyclovir due to the risk of overdose.

Other Important Drug and Substance Interactions

Caution is advised with alcohol as it may worsen some side effects. Valacyclovir may also reduce the effectiveness of live vaccines like varicella or zoster. Limited data exists on herbal supplements and valacyclovir interactions, but informing your doctor about all supplements is recommended. For a more detailed list of interactions, refer to resources like {Link: SingleCare https://www.singlecare.com/blog/valacyclovir-interactions/}.

Comparison of Valacyclovir Interactions

Interacting Substance/Class	Examples	Mechanism of Interaction	Potential Outcomes
Nephrotoxic Agents	NSAIDs (ibuprofen), Immunosuppressants (cyclosp­orine), Aminoglycoside Antibiotics (gentami­cin)	Increased strain on kidney function, reduced clearance of valacyclovir/acyclovir	Acute Kidney Injury (AKI), increased systemic toxicity
Renal Clearance Inhibitors	Probenecid, Cimetidine	Slowed elimination of acyclovir from the kidneys, resulting in higher blood levels	Increased risk of valacyclovir-related side effects (e.g., neurological)
Other Antivirals	Acyclovir, Famciclovir, Valganciclovir	Overdose due to the body converting valacyclovir into acyclovir, adding to the total drug load	Increased risk of severe adverse effects, including overdose symptoms and central nervous system issues
Alcohol	Beer, Wine, Liquor	Worsened side effects (dizziness, nausea); potential liver strain with excessive use; weakened immune system	Amplified side effects, possible liver damage, impaired immune response
Live Vaccines	Varicella vaccine, Zoster vaccine	Possible reduction in the effectiveness of the vaccine	Lack of protective immunity from vaccination

Conclusion

Knowing what you cannot take with valacyclovir is crucial for safety. The main risks involve drugs affecting kidney function due to valacyclovir's renal clearance. Be cautious with NSAIDs, immunosuppressants, certain antibiotics, and alcohol. Openly communicate all medications and supplements with your doctor to minimize interaction risks and ensure safe, effective treatment. Always follow medical instructions and report unusual symptoms. For more information on medication safety, refer to resources like the Mayo Clinic.

Disclaimer: This information is for educational purposes and is not a substitute for professional medical advice. Always consult with a healthcare provider for any health concerns or before making decisions related to your treatment.

Frequently Asked Questions

Can I take ibuprofen or other NSAIDs with valacyclovir?

It is generally recommended to avoid taking ibuprofen or other NSAIDs with valacyclovir as combining them increases the risk of kidney damage. Always consult your doctor.

Is it safe to drink alcohol while taking valacyclovir?

It is best to limit or avoid alcohol. It can worsen side effects like dizziness and nausea and potentially strain the liver and kidneys, as both are processed by these organs.

Can I take other antiviral medications with valacyclovir?

You should not take valacyclovir with other antivirals that convert to acyclovir, like acyclovir, famciclovir, or valganciclovir, to avoid overdose and serious side effects.

What effect does probenecid have on valacyclovir?

Probenecid can reduce the kidney's ability to clear acyclovir, leading to higher blood levels and increased side effects. This combination requires close medical supervision.

What should I know about taking immunosuppressants with valacyclovir?

Caution is needed with immunosuppressants like cyclosporine and tacrolimus. Both can affect kidneys, and combined use increases toxicity risk, particularly in transplant patients.

Does valacyclovir interact with live vaccines?

Yes, valacyclovir can interact with live vaccines like varicella or zoster, potentially reducing their effectiveness. Consult your healthcare provider about timing.

Why is proper hydration so important when taking valacyclovir?

Proper hydration is vital because valacyclovir is cleared by the kidneys. Drinking ample water helps kidney function, preventing potential kidney problems and crystalluria.