Valacyclovir 1gm Tablets

Valacyclovir is a prodrug of acyclovir. It is rapidly and almost completely converted to acyclovir and L-valine by first-pass intestinal and hepatic metabolism. Acyclovir is a synthetic purine nucleoside analog with in vitro and in vivo inhibitory activity against herpes simplex virus types 1 (HSV-1), 2 (HSV-2), and varicella-zoster virus (VZV). Acyclovir is phosphorylated to its active form, acyclovir triphosphate, by viral thymidine kinase (TK) within infected cells. Acyclovir triphosphate then inhibits viral DNA synthesis by competing with deoxyguanosine triphosphate for incorporation into viral DNA by viral DNA polymerase, leading to chain termination and irreversible inactivation of the viral DNA polymerase.

Serious Side Effects: Seek Medical Attention Immediately

Although rare, this medication can cause severe and potentially life-threatening side effects. If you experience any of the following symptoms, contact your doctor or seek medical help right away:

Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of kidney problems, including:
+ Inability to pass urine
+ Changes in urine output
+ Blood in the urine
+ Sudden weight gain
Confusion
Changes in behavior
Mood changes
Hallucinations (seeing or hearing things that are not there)
Difficulty speaking
Shakiness, trouble moving around, or stiffness
Seizures
Blood problems, such as thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS), which can be life-threatening. If you experience any of the following, seek medical help immediately:
+ Extreme fatigue or weakness
+ Bruising or bleeding
+ Dark urine or yellow skin and eyes
+ Pale skin
+ Changes in urine output
+ Changes in vision
+ Weakness or numbness on one side of the body
+ Trouble speaking or thinking
+ Balance problems
+ Fever

Other Possible Side Effects

Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects, contact your doctor or seek medical help if they bother you or do not go away:

Headache
Upset stomach or vomiting
Stomach pain
Diarrhea
Fatigue or weakness
Menstrual pain

This list is not exhaustive, and you may experience other side effects not mentioned here. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.

Before Taking This Medication: Important Information to Share with Your Doctor

It is essential to inform your doctor about the following:

Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the symptoms you experienced as a result of the allergy.
All medications you are currently taking, including prescription and over-the-counter (OTC) drugs, natural products, and vitamins. This information will help your doctor and pharmacist assess potential interactions between this medication and other substances you are taking.
* Any existing health problems, as this medication may interact with certain conditions.

To ensure your safety, it is crucial to verify that this medication can be taken safely with all your other medications and health conditions. Never start, stop, or adjust the dosage of any medication without first consulting your doctor.

It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. Adhere to the prescribed duration of treatment, as taking this drug for longer than recommended by your doctor is not advised.

If you are using this medication to treat cold sores, be aware that it will not provide a cure. Discuss the treatment and management of cold sores with your doctor to understand the role of this medication in your care.

This drug is not a cure for herpes infections, and it is crucial to consult with your doctor to understand its limitations and how to manage your condition effectively.

For individuals with genital herpes, it is vital to note that this medication will not prevent the spread of the infection. To minimize the risk of transmission, avoid any form of sexual activity when you have active sores or other symptoms of genital herpes. Even in the absence of visible symptoms, genital herpes can still be transmitted. Therefore, it is recommended to use a latex or polyurethane condom during sexual activity. Consult your doctor for guidance on preventing the spread of genital herpes.

If you are 65 years or older, exercise caution when using this medication, as you may be more susceptible to side effects.

Pregnant women, those planning to become pregnant, or breastfeeding mothers should inform their doctor, as it is necessary to discuss the potential benefits and risks of this medication to both the mother and the baby.

• Mycophenolate mofetil (increased plasma concentrations of both drugs, especially in renal impairment)
• Probenecid (decreases renal clearance of acyclovir, increasing acyclovir levels)

• Cimetidine (may increase acyclovir levels, less significant than probenecid)
• Nephrotoxic drugs (e.g., NSAIDs, cyclosporine, tacrolimus, aminoglycosides, foscarnet) - concurrent use may increase risk of renal dysfunction.

• Signs of central nervous system (CNS) toxicity (e.g., agitation, confusion, hallucinations, dizziness, seizures, tremors, somnolence)
• Signs of renal dysfunction (e.g., decreased urine output, flank pain, edema)
• Unusual bruising or bleeding (rare, but possible thrombotic thrombocytopenic purpura/hemolytic uremic syndrome in immunocompromised patients)

Category B. Studies in animals have not shown fetal harm. Limited human data suggest no increased risk of birth defects. Use during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Acyclovir (the active metabolite of valacyclovir) is excreted into breast milk. Infant exposure is low, and adverse effects in breastfed infants are not expected. Considered L2 (likely compatible).

Approved for herpes labialis in adolescents ≥12 years of age. Safety and efficacy in children <12 years of age have not been established for other indications. Dosing for chickenpox in children (2 to <18 years) is available for acyclovir, but not specifically FDA-approved for valacyclovir.

Elderly patients are more likely to have age-related decreases in renal function, which can lead to increased acyclovir exposure and a higher risk of adverse effects, particularly CNS and renal. Dose adjustment based on creatinine clearance is crucial in this population. Adequate hydration is also important.

• Valacyclovir is a prodrug of acyclovir, offering improved oral bioavailability and less frequent dosing compared to acyclovir.
• Renal dose adjustment is critical to prevent accumulation of acyclovir, which can lead to neurotoxicity (e.g., confusion, hallucinations, seizures) and nephrotoxicity.
• Advise patients to maintain adequate hydration, especially during high-dose therapy, to minimize the risk of renal crystallization.
• Valacyclovir treats viral infections but does not cure them; it helps manage symptoms and reduce the frequency/severity of outbreaks.
• Patients should be advised that valacyclovir does not prevent transmission of herpes viruses and appropriate precautions (e.g., avoiding contact during outbreaks, using condoms) should still be taken.

• Acyclovir (Zovirax)
• Famciclovir (Famvir)

If your symptoms or health issues persist or worsen, it is essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so it's a good idea to check with your pharmacist. If you have any questions or concerns about this medication, don't hesitate to discuss them with your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When seeking help, be prepared to provide detailed information about the overdose, including the medication taken, the amount, and the time it occurred.