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Therapeutic Class: Antiviral
Pharmacologic Class: Viral DNA Polymerase Inhibitor
Chemical Class: Guanosine Nucleoside Analog
Valacyclovir is used to treat herpes virus infections, including herpes labialis (also known as cold sores), herpes zoster (also known as shingles), and herpes simplex (also known as genital herpes) in adults. It is also used to treat chickenpox and cold sores in children.
In your body, valacyclovir becomes the anti-herpes medicine, acyclovir. Although valacyclovir will not cure shingles or genital herpes, it does help relieve the pain and discomfort and helps the sores heal faster.
Valacyclovir is available only with your doctor's prescription.
In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For valacyclovir, the following should be considered:
Tell your doctor if you have ever had any unusual or allergic reaction to valacyclovir or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.
Appropriate studies have not been performed on the relationship of age to the effects of valacyclovir in children below 12 years of age with cold sores, and children below 2 years of age with chickenpox. Safety and efficacy have not been established.
Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of valacyclovir in the elderly. However, elderly patients are more likely to have age-related kidney disease, which may require an adjustment in the dose of patients receiving valacyclovir.
|All Trimesters||B||Animal studies have revealed no evidence of harm to the fetus, however, there are no adequate studies in pregnant women OR animal studies have shown an adverse effect, but adequate studies in pregnant women have failed to demonstrate a risk to the fetus.|
Studies in women suggest that this medication poses minimal risk to the infant when used during breastfeeding.
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking valacyclovir, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using valacyclovir with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.
The presence of other medical problems may affect the use of valacyclovir. Make sure you tell your doctor if you have any other medical problems, especially:
Valacyclovir works best if it is used within 48 hours after the first symptoms of shingles or genital herpes (e.g., pain, burning, or blisters) begin to appear. For recurrent outbreaks of genital herpes, valacyclovir works best if it is used within 24 hours after the symptoms begin to appear.
If you are taking valacyclovir for the treatment of chickenpox, it is best to start taking valacyclovir as soon as possible after the first sign of the chickenpox rash appears, usually within one day.
Valacyclovir may be taken with meals or on an empty stomach.
If you are using the oral suspension, use a specially marked measuring spoon or other device to measure each dose accurately. The average household teaspoon may not hold the right amount of liquid.
Drink extra fluids so you will pass more urine while you are using valacyclovir. This will keep your kidneys working well and help prevent kidney problems.
To help clear up your infection, keep taking valacyclovir for the full time of treatment, even if your symptoms begin to clear up after a few days. Do not miss any doses. However, do not use valacyclovir more often or for a longer time than your doctor ordered.
The dose of valacyclovir will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of valacyclovir. If your dose is different, do not change it unless your doctor tells you to do so.
The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
If you miss a dose of valacyclovir, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.
Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.
Keep out of the reach of children.
Do not keep outdated medicine or medicine no longer needed.
Ask your healthcare professional how you should dispose of any medicine you do not use.
If you or your child's symptoms do not improve within a few days, or if they become worse, check with your doctor.
The areas affected by genital herpes, chickenpox, or shingles should be kept as clean and dry as possible. Also, wear loose-fitting clothing to avoid irritating the sores (blisters).
It is important to remember that valacyclovir will not keep you from spreading herpes to others.
Herpes infection of the genitals can be caught from or spread to your partner during any sexual activity. Even though you may get herpes if your partner has no symptoms, the infection is more likely to be spread if sores are present. This is true until the sores are completely healed and the scabs have fallen off. Therefore, it is best to avoid any sexual activity if either you or your sexual partner has any symptoms of herpes. The use of a latex condom (“rubber") may help prevent the spread of herpes. However, spermicidal (sperm-killing) jelly or a diaphragm will probably not help.
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:More common
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:More common
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
See also: Side effects (in more detail)
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It is possible that some side effects of valacyclovir may not have been reported. These can be reported to the FDA here. Always consult a healthcare professional for medical advice.
Applies to valacyclovir: oral tablet
As well as its needed effects, valacyclovir may cause unwanted side effects that require medical attention.
If any of the following side effects occur while taking valacyclovir, check with your doctor immediately:More common
Some valacyclovir side effects may not need any medical attention. As your body gets used to the medicine these side effects may disappear. Your health care professional may be able to help you prevent or reduce these side effects, but do check with them if any of the following side effects continue, or if you are concerned about them:More common
Applies to valacyclovir: oral tablet
Gastrointestinal side effects have included nausea (up to 15%), abdominal pain (up to 11%), and vomiting (up to 6%). Constipation, anorexia, diarrhea, elevated amylase, and elevated serum lipase have been reported. Diarrhea has been reported during postmarketing experience. In clinical trials of otherwise healthy individuals, frequencies were higher for patients over 50 years of age than for younger patients.[Ref]
Nervous system side effects have included headache (up to 38%) and dizziness (up to 4%). Central nervous system effects including agitation, seizures, and encephalopathy have been reported. Choreiform movements, myoclonus, vasculitic mononeuritis multiplex, somnolence, and Cotard's syndrome have been reported. Agitation, ataxia, coma, decreased consciousness, dysarthria, encephalopathy, seizures, and tremors have been reported during postmarketing experience. Neurotoxicity has been most commonly reported in patients with renal failure, the elderly, and in patients following bone marrow transplant, and is associated with high serum concentrations of acyclovir.[Ref]
Acyclovir neurotoxicity is almost exclusively seen in patients with renal failure. These patients may have longstanding chronic renal failure, or acute failure which may be attributed to acyclovir. One group of six bone marrow transplant patients exhibited abnormal EEGs with diffuse slowing. Although more commonly seen with intravenous administration of higher doses, neurotoxicity has also been reported in patients receiving oral doses of acyclovir. Following discontinuation of therapy, mental status recovered within about a week. Several patients with chronic renal failure exhibiting neurotoxicity improved dramatically following hemodialysis.
Although there have been no similar reports in clinical trials of valacyclovir completed to date, the assumption may be made that neurotoxicity can also occur with valacyclovir based on the fact that plasma acyclovir concentrations from oral valacyclovir administration tend to be much higher than those obtained with oral acyclovir.[Ref]
Psychiatric side effects have included depression (up to 7%) and disorientation. Central nervous system effects including hallucinations, confusion, and delirium have been reported. Aggressive behavior, confusion, mania, and psychosis (including auditory and visual hallucinations) have been reported during postmarketing experience.
Transient renal dysfunction has been reported with both oral and intravenous administration of acyclovir. Crystallization of the drug in the renal tubules is thought to be the mechanism for the development of renal dysfunction based on findings of crystalluria in several case reports and at least one prospective study. Inadequate hydration of the patient and rapid administration of the drug may contribute to the development of crystalluria. Acute tubular necrosis and interstitial nephritis have also been reported in association with acyclovir therapy. Although there have been no similar reports in clinical trials of valacyclovir completed to date, the assumption may be made that renal toxicity can also occur with valacyclovir based on the fact that plasma acyclovir concentrations from oral valacyclovir administration tend to be much higher than those obtained with oral acyclovir.[Ref]
Renal side effects have included acute renal failure, elevated serum creatinine (up to 0.7%), renal toxicity, and renal failure (presenting as an increase in serum creatinine and blood urea nitrogen). Renal failure and renal pain (may be associated with renal failure) have been reported during postmarketing experience. Renal effects are transient and resolve over several days following discontinuation of therapy. Renal damage is most likely due to crystallization of acyclovir in the renal tubules. Patients with preexisting renal insufficiency are at greater risk for developing neurotoxicity and further deterioration in renal function.[Ref]
Hematologic side effects have included thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS), and decreased neutrophil counts (18%), platelet counts (up to 3%), hemoglobin (up to 0.8%), and white blood cells (up to 1.3%). Thrombocytopenia, aplastic anemia, leukocytoclastic vasculitis, and TTP/HUS have been reported during postmarketing experience.[Ref]
TTP/HUS, including some fatalities, has been reported during clinical trials in patients with advanced HIV disease and in allogeneic bone marrow transplant and renal transplant recipients, who were receiving 8 g valacyclovir per day.[Ref]
Hepatic side effects have included elevated AST (up to 16%), ALT (up to 14%), and bilirubin. Liver enzyme abnormalities and hepatitis have been reported during postmarketing experience.[Ref]
Hypersensitivity side effects have included acute hypersensitivity reactions (including anaphylaxis, angioedema, dyspnea, pruritus, rash, and urticaria) during postmarketing experience. Stevens-Johnson syndrome has been reported.[Ref]
Dermatologic side effects have included rash (8%). Erythema multiforme, rashes including photosensitivity, and alopecia have been reported during postmarketing experience.[Ref]
Cardiovascular side effects have included hypertension and tachycardia during postmarketing experience.[Ref]
Ocular side effects have included visual abnormalities during postmarketing experience.[Ref]
Respiratory side effects have included nasopharyngitis (16%) and upper respiratory tract infection (9%).[Ref]
Musculoskeletal side effects have included arthralgia (up to 6%).[Ref]
Genitourinary side effects have included dysmenorrhea (up to 8%).[Ref]
Other side effects have included fatigue (8%). Facial edema has been reported during postmarketing experience.[Ref]
Metabolic side effects have included elevated alkaline phosphatase (4%) and hypoglycemia. At least one case of hypercalcemia has been reported.[Ref]
1. Hellden A, Odar-Cederlof I, Larsson K, Fehrman-Ekholm I, Linden T "Death delusion." BMJ 335 (2007): 1305
2. Abudalu M, Tyring S, Koltun W, Bodsworth N, Hamed K "Single-day, patient-initiated famciclovir therapy versus three-day valacyclovir regimen for recurrent genital herpes: a randomized, double-blind, comparative trial." Clin Infect Dis 47 (2008): 651-8
3. Fife KH, Warren TJ, Ferrera RD, et al. "Effect of valacyclovir on viral shedding in immunocompetent patients with recurrent herpes simplex virus 2 genital herpes: a US-based randomized, double-blind, placebo-controlled clinical trial." Mayo Clin Proc 81 (2006): 1321-7
4. Sheffield JS, Hill JB, Hollier LM, et al. "Valacyclovir prophylaxis to prevent recurrent herpes at delivery: a randomized clinical trial." Obstet Gynecol 108 (2006): 141-7
5. Wald A "New therapies and prevention strategies for genital herpes." Clin Infect Dis 28 (1999): s4-13
6. Beutner KR, Friedman DJ, Forszpaniak C, Andersen PL, Wood MJ "Valaciclovir compared with acyclovir for improved therapy for herpes zoster in immunocompetent adults." Antimicrob Agents Chemother 39 (1995): 1546-53
7. "Product Information. Valtrex (valacyclovir)." Glaxo Wellcome, Research Triangle Park, NC.
8. Dworkin RH, Johnson RW, Breuer J, et al. "Recommendations for the management of herpes zoster." Clin Infect Dis 44 Suppl 1 (2007): S1-S26
9. Feldman S, Rodman J, Gregory B "Excessive serum concentrations of acyclovir and neurotoxicity." J Infect Dis 157 (1988): 385-8
10. Pary LF, Henszel A, Kelkar P "Vasculitic mononeuritis multiplex induced by valacyclovir." Neurology 62 (2004): 1906-7
11. Wade JC, Meyers JD "Neurologic symptoms associated with parenteral acyclovir treatment after marrow transplantation." Ann Intern Med 98 (1983): 921-5
12. Jones PG, Beier-Hanratty SA "Acyclovir: neurologic and renal toxicity." Ann Intern Med 104 (1986): 892
13. Okada T, Nakao T, Matsumoto H, et al. "Valacyclovir neurotoxicity in a patient with end-stage renal disease treated with continuous ambulatory peritoneal dialysis." Clin Nephrol 58 (2002): 168-70
14. Rivkin AM "Valacyclovir-induced seizures in end-stage renal disease." Ann Pharmacother 37 (2003): 1913
15. Cohen SM, Minkove JA, Zebley JW, Mulholland JH "Severe but reversible neurotoxicity from acyclovir." Ann Intern Med 100 (1984): 920
16. Kimberlin DF, Weller S, Whitley R, Andrews WW, Hauth JC, Lakeman F, Miller G "Pharmacokinetics of oral valacyclovir and acyclovir in late pregnancy." Am J Obstet Gynecol 179 (1998): 846-51
17. Becker BN, Fall P, Hall C, Milam D, Leonard J, Glick A, Schulman G "Rapidly progressive acute renal failure due to acyclovir: case report and review of the literature." Am J Kidney Dis 22 (1993): 611-5
18. Slifkin M, Doron S, Snydman DR "Viral prophylaxis in organ transplant patients." Drugs 64 (2004): 2763-92
19. Bean B, Aeppli D "Adverse effects of high-dose intravenous acyclovir in ambulatory patients with acute herpes zoster." J Infect Dis 151 (1985): 362-5
20. Reischig T, Jindra P, Mares J, et al. "Valacyclovir for Cytomegalovirus Prophylaxis Reduces the Risk of Acute Renal Allograft Rejection." Transplantation 79 (2005): 317-324
21. Tomson CR, Goodship TH, Rodger RS "Psychiatric side-effects of acyclovir in patients with chronic renal failure." Lancet 2 (1985): 385-6
22. Rashiq S, Briewa L, Mooney M, Giancarlo T, Khatib R, Wilson FM "Distinguishing acyclovir neurotoxicity from encephalomyelitis." J Intern Med 234 (1993): 507-11
23. LinssenSchuurmans CD, vanKan EJM, Feith GW, Uges DRA "Neurotoxicity caused by valacyclovir in a patient on hemodialysis." Ther Drug Monit 20 (1998): 385-6
24. Gill MJ, Burgess E "Neurotoxicity of acyclovir in end stage renal disease." J Antimicrob Chemother 25 (1990): 300-1
25. MacDiarmaid-Gordon AR, O'Connor M, Beaman M, Ackrill P "Neurotoxicity associated with oral acyclovir in patients undergoing dialysis." Nephron 62 (1992): 280-3
26. Maru MC, Fialkow RZ, Haria DM "Choreiform movements in dialysis patient taking valacyclovir and famciclovir." South Med J 94 (2001): 655
27. Fletcher CV, Chinnock BJ, Chace B, Balfour HH "Pharmacokinetics and safety of high-dose oral acyclovir for suppression of cytomegalovirus disease after renal transplantation." Clin Pharmacol Ther 44 (1988): 158-63
28. Krieble BF, Rudy DW, Glick MR, Clayman MD "Case report: acyclovir neurotoxicity and nephrotoxicity--the role for hemodialysis." Am J Med Sci 305 (1993): 36-9
29. O'Brien JJ, Campoli-Richards DM "Acyclovir: an updated review of its antiviral activity, pharmacokinetic properties and therapeutic efficacy." Drugs 37 (1989): 233-309
30. Beales P, Almond MK, Kwan JTC "Acyclovir neurotoxicity following oral therapy - prevention and treatment in patients on haemodialysis." Nephron 66 (1994): 362-3
31. Mataix AL, Duarte J, Revuelta K, et al. "Oral acyclovir and neurologic adverse effects in endstage renal disease." Ann Pharmacother 28 (1991): 961-2
32. Rashed A, Asadeh B, Romeh SHA "Acyclovir-induced acute tubulo-interstitial nephritis." Nephron 56 (1990): 436-8
33. Sawyer MH, Webb DE, Balow JE, Straus SE "Acyclovir-induced renal failure." Am J Med 84 (1988): 1067-71
34. Izzedine H, Launay-Vacher V, Deray G "Antiviral drug-induced nephrotoxicity." Am J Kidney Dis 45 (2005): 804-17
35. Roberts DM, Smith MW, McMullan BJ, Sevastos J, Day RO "Acute kidney injury due to crystalluria following acute valacyclovir overdose." Kidney Int 79 (2011): 574
36. Hernandez E, Praga M, Moreno F, Montoyo C "Acute renal failure induced by oral acyclovir." Clin Nephrol 36 (1991): 155-6
37. Gnann JW, Barton NH, Whitley RJ "Acyclovir: mechanism of action, pharmacokinetics, safety and clinical applications." Pharmacotherapy 3 (1983): 275-83
38. Peterslund NA, Larsen ML, Mygind H "Acyclovir crystalluria." Scand J Infect Dis 20 (1988): 225-8
39. Bianchetti MG, Roduit C, Oetliker OH "Acyclovir-induced renal failure: course and risk factors." Pediatr Nephrol 5 (1991): 238-9
40. Rivaud E, Massiani MA, Vincent F, Azoulay E, Couderc LJ "Valacyclovir hydrochloride therapy and thrombotic thrombocytopenic purpura in a HIV-infected patient." Arch Intern Med 160 (2000): 1705-6
41. Jacobson MA, Gallant J, Wang LH, Coakley D, Weller S, Gary D, Squires L, Smiley ML, Blum MR, Feinberg J "Phase I trial of valaciclovir, the L-valyl ester of acyclovir, in patients with advanced human immunodeficiency virus disease." Antimicrob Agents Chemother 38 (1994): 1534-40
42. Mindel A, Carney O. Freris M, Faherty A, Patou G, Williams P "Dosage and safety of long-term suppressive acyclovir therapy for recurrent genital herpes." Lancet Apr (1988): 926-8
43. Fazal BA, Turett GS, Justman JE, Hall G, Telzak EE "Stevens-johnson syndrome induced by treatment with acyclovir." Clin Infect Dis 21 (1995): 1038-9
44. Cheungpasitporn W, Suksaranjit P, Chanprasert S "Hypercalcemia in human immunodeficiency virus-related lymphoma and valacyclovir toxicity." Am J Med Sci 342 (2011): 539
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