Is there anything you can't take with valacyclovir? A Guide to Drug Interactions

Globally, an estimated 3.8 billion people under age 50 have herpes simplex virus type 1 (HSV-1), an infection commonly treated with valacyclovir [1.7.1]. But is there anything you can't take with valacyclovir? Understanding its interactions is crucial for safety and efficacy.

Quick Summary

Valacyclovir can interact with drugs that affect the kidneys, such as certain pain relievers (NSAIDs), other antivirals, and some antibiotics. Combining them can increase the risk of kidney damage.

Key Points

• Main Risk: The most significant interactions with valacyclovir involve other drugs that are also hard on the kidneys, increasing the risk of acute kidney injury [1.6.5].

• Avoid NSAIDs: You should generally avoid taking NSAIDs like ibuprofen (Advil) and naproxen (Aleve) with valacyclovir due to the increased risk of kidney damage [1.3.1, 1.3.6].

• Safe Pain Relief: Acetaminophen (Tylenol) is considered a safer pain relief option as it doesn't have the same effect on the kidneys and is not known to interact with valacyclovir [1.8.5].

• Tell Your Doctor Everything: Inform your healthcare provider about all prescription, over-the-counter medications, and supplements you use to screen for interactions [1.3.1].

• Stay Hydrated: Drinking plenty of fluids is crucial while taking valacyclovir to help protect your kidneys from potential damage [1.6.5].

• Alcohol Caution: While there is no direct interaction, it is often advised to limit alcohol as it can worsen side effects like dizziness and put extra strain on the liver [1.5.1, 1.5.3].

• Other Prescriptions: Be cautious with other antivirals (like tenofovir), certain antibiotics (like gentamicin), and immunosuppressants (like cyclosporine) [1.2.1, 1.2.4].

Understanding Valacyclovir

Valacyclovir, often known by its brand name Valtrex, is an antiviral medication prescribed to treat infections caused by the herpes virus family [1.9.3, 1.9.4]. This includes herpes zoster (shingles), herpes simplex genitalis (genital herpes), and herpes labialis (cold sores) [1.2.3]. Valacyclovir is a prodrug, which means the body converts it into its active form, acyclovir, after ingestion [1.4.2]. This process allows for higher absorption and less frequent dosing compared to taking acyclovir directly [1.4.3]. While it doesn't cure these viral infections, it helps to decrease the severity and duration of outbreaks, relieve pain, and help sores heal faster [1.9.2].

The Critical Role of Your Kidneys

Valacyclovir is primarily cleared from the body by the kidneys [1.6.3]. Because of this, its main safety concern involves kidney health. Taking valacyclovir, especially at high doses or for long periods, can pose a risk of kidney problems, including acute kidney injury (AKI) [1.6.5]. This risk is heightened in individuals with pre-existing kidney disease, the elderly, those who are dehydrated, or those taking other medications that are also hard on the kidneys [1.3.1, 1.6.5]. The most common mechanism of kidney injury is the formation of crystals in the renal tubules, which can cause obstruction and damage [1.6.2]. Therefore, staying well-hydrated is essential while taking this medication to help keep the kidneys functioning properly and prevent these issues [1.9.3].

Major Drug Interactions to Be Aware Of

The most significant interactions with valacyclovir involve other drugs that can also strain the kidneys, known as nephrotoxic drugs. Combining these medications can amplify the risk of kidney damage [1.3.2, 1.6.5].

Nonsteroidal Anti-Inflammatory Drugs (NSAIDs)

One of the most common groups of interacting drugs is NSAIDs. While people often reach for these over-the-counter pain relievers, combining them with valacyclovir can be risky. Studies have shown that taking valacyclovir and an NSAID at the same time is associated with a significantly higher reporting frequency of acute kidney injury compared to taking either drug alone [1.3.4, 1.3.6].

• Examples of NSAIDs to be cautious with include: Ibuprofen (Advil, Motrin), Naproxen (Aleve), Diclofenac, and Ketorolac [1.3.3, 1.3.4].
• Safer Alternative for Pain: Acetaminophen (Tylenol) is generally considered a safer option for pain relief as it does not typically affect the kidneys in the same way and is not known to interact with valacyclovir [1.8.4, 1.8.5].

Other Prescription Medications

Several other classes of prescription drugs can interact with valacyclovir, primarily by increasing the load on the kidneys or affecting how the drug is cleared from the body. It is vital to inform your doctor of all medications you are taking.

• Other Antivirals: Drugs like Tenofovir, Foscarnet, and Cidofovir can be nephrotoxic and should be used with caution [1.2.1, 1.4.3]. Taking valacyclovir and acyclovir together is not recommended as it can lead to higher concentrations and increase the risk of toxicity [1.4.3].
• Antibiotics: Certain intravenous (IV) antibiotics, such as vancomycin, amikacin, and gentamicin, can cause kidney problems and may increase this risk when taken with valacyclovir [1.2.4, 1.3.3].
• Immunosuppressants: Medications used to prevent organ transplant rejection, such as Mycophenolate Mofetil, Tacrolimus, and Cyclosporine, can be hard on the kidneys [1.2.1, 1.2.4].
• Other Drugs: Probenecid (used for gout) and Cimetidine (an acid reducer) can increase the levels of valacyclovir in the body, which might increase the risk of side effects [1.2.4, 1.3.2]. Lithium and Methotrexate may also interact [1.2.3, 1.2.4].

Valacyclovir Drug Interaction Comparison

Drug Class	Examples	Risk Level	Primary Concern
NSAIDs	Ibuprofen, Naproxen, Diclofenac	High	Increased risk of acute kidney injury [1.3.4, 1.3.6].
Certain Antivirals	Tenofovir, Foscarnet	Moderate to High	Additive strain on the kidneys [1.2.1, 1.4.3].
Certain Antibiotics	Vancomycin, Gentamicin	Moderate	Increased risk of kidney damage [1.2.4].
Immunosuppressants	Cyclosporine, Tacrolimus	Moderate	Potential for combined kidney toxicity [1.2.4].
Gout/Acid Reducers	Probenecid, Cimetidine	Low to Moderate	Can increase valacyclovir levels in the blood [1.3.2].
Pain Relievers	Acetaminophen (Tylenol)	Low	Generally considered safe to take together [1.8.4].

Lifestyle and Other Considerations

Alcohol

There is no direct, formal drug interaction between valacyclovir and alcohol, and medical professionals generally agree that alcohol does not stop the medication from working [1.5.1]. However, it is often recommended to limit or avoid alcohol during treatment [1.5.3, 1.5.6]. Both substances are processed by the liver, and combining them can put extra strain on this organ [1.5.1]. Alcohol can also worsen common side effects of valacyclovir like dizziness, nausea, and headaches [1.5.3]. Furthermore, alcohol consumption can weaken the immune system, which is counterproductive when fighting a viral infection [1.5.5].

Hydration and Vaccines

Staying well-hydrated by drinking plenty of fluids is one of the most important things you can do while taking valacyclovir to protect your kidneys [1.6.5]. Also, be aware that antiviral medications like valacyclovir can diminish the effectiveness of live attenuated vaccines, such as the varicella (chickenpox) vaccine. You should not take valacyclovir within a specific window before and after getting these vaccines [1.4.3].

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Conclusion

While valacyclovir is an effective antiviral, the answer to, 'Is there anything you can't take with valacyclovir?' is a definitive yes. The primary concern is with other drugs that can harm the kidneys, most notably common NSAIDs like ibuprofen. Interactions also exist with other antivirals, certain antibiotics, and immunosuppressants. Always tell your healthcare provider about all prescription drugs, over-the-counter medications, and supplements you are taking to avoid harmful interactions [1.3.1]. Staying hydrated and limiting alcohol can further ensure your treatment is both safe and effective.

For more detailed information, you can visit the Mayo Clinic's page on Valacyclovir.

Frequently Asked Questions

Can I take Tylenol (acetaminophen) with valacyclovir?

Yes, acetaminophen (Tylenol) is generally considered safe to take with valacyclovir for pain relief, as it is not known to have a direct interaction [1.8.4, 1.8.5].

Is it safe to take ibuprofen (Advil) with valacyclovir?

It is best to avoid NSAIDs like ibuprofen unless your healthcare provider says it's safe. The combination significantly increases the risk of kidney problems, including acute kidney injury [1.3.1, 1.3.6].

Can I drink alcohol while taking valacyclovir?

While there isn't a direct interaction that stops the drug from working, it's generally recommended to limit or avoid alcohol. Alcohol can worsen side effects like dizziness and nausea and put additional strain on your liver [1.5.1, 1.5.3].

What are the signs of a bad drug interaction with valacyclovir?

Signs of a serious interaction, particularly kidney injury, include a decrease in the amount of urine, swelling in your feet or ankles, feeling tired, and shortness of breath [1.2.3, 1.6.6]. Neurological signs like confusion or hallucinations can also occur [1.6.1].

Does valacyclovir interact with antibiotics?

Yes, valacyclovir can interact with certain antibiotics, especially those known to affect the kidneys like amikacin, gentamicin, and vancomycin [1.2.4, 1.3.3].

Do I need to tell my doctor about vitamins and supplements?

Yes, you should always tell your doctor about all prescription drugs, over-the-counter medicines, vitamins, and supplements you are taking to ensure there are no harmful interactions [1.6.4].

Why is it important to drink a lot of water with valacyclovir?

Drinking extra fluids helps you urinate more, which keeps your kidneys working well and helps prevent kidney problems. This is because valacyclovir is cleared by the kidneys and can sometimes form crystals that cause damage if you are not well-hydrated [1.6.5, 1.9.3].