"The Food and Drug Administration (FDA) has approved the approval of Qutenza (capsaicin) 8% patch, a medicated skin patch that relieves the pain of post-herpetic neuralgia (PHN), a serious complication that can occur after a bout with shingles."...
Zovirax Side Effects Center
Medical Editor: Charles Patrick Davis, MD, PhD
Zovirax (acyclovir) is a synthetic nucleoside analogue that interferes with the replication of herpes viruses used to treat
- loss of appetite,
- stomach pain,
- swelling in your hands and feet,
- and feeling unwell (malaise).
Zovirax tablets are available in 200, 400 and 800 mg strengths and as a liquid suspension with 200 mg strength per 5 ml. Usual doses are 800 mg every 4 hours, 5 times a day for 10 days for shingles; doses for genital herpes infection are the same interval but start with 200 mg. Doses for chickenpox is the same as shingles except it goes for only 5 days for adults; for children ages 2 and up are weight based (20 mg per Kg) up to 40 Kg, 5 times a day for 5 days. Over 40 Kg, the person gets the adult dose for 5 days. Zovirax may interact with probenecid. Tell your doctor all medications and supplements you use. There are no good studies on pregnant women. Zovirax may be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Caution is advised with use of Zovirax in women who are breastfeeding since the drug is secreted in breast milk. Safety and efficacy has not been studied in pediatric patients below the age of 2 years.
Our Zovirax Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
What is Patient Information in Detail?
Easy-to-read and understand detailed drug information and pill images for the patient or caregiver from Cerner Multum.
Zovirax in Detail - Patient Information: Side Effects
Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have any of these serious side effects:
- pain in your lower back;
- urinating less than usual or not at all;
- easy bruising or bleeding; or
- unusual weakness.
Less serious side effects may include:
- nausea, vomiting, diarrhea, loss of appetite, stomach pain;
- headache, feeling light-headed; or
- swelling in your hands or feet.
Read the entire detailed patient monograph for Zovirax (Acyclovir)
What is Patient Information Overview?
A concise overview of the drug for the patient or caregiver from First DataBank.
Zovirax Overview - Patient Information: Side Effects
Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
Tell your doctor immediately if any of these unlikely but serious side effects occur: dizziness, drowsiness, signs of kidney problems (such as a change in the amount of urine, unusual back/side pain), mental/mood changes (such as agitation, confusion, hallucinations), shaky/unsteady movement, trouble speaking.
This medication may rarely cause a life-threatening disorder that affects the blood cells, kidneys, and other parts of the body. This disorder is more likely to occur if you have conditions related to a weakened immune system (such as HIV disease, bone marrow transplant, kidney transplant). Seek immediate medical attention if any of these rare but serious side effects occur: extreme tiredness, slow/fast/irregular heartbeat, easy bruising/bleeding, new fever, bloody/dark urine, severe stomach/abdominal pain, yellowing eyes/skin, sudden vision changes, loss of consciousness, seizures.
A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US -
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
Read the entire patient information overview for Zovirax (Acyclovir)
What is Prescribing information?
The FDA package insert formatted in easy-to-find categories for health professionals and clinicians.
Zovirax FDA Prescribing Information: Side Effects
Adverse Drug Reaction Overview
The most frequent adverse reactions associated with the use of ZOVIRAX® (acyclovir) are headache and nausea.
Neurological side effects have also been reported in rare instances. Elderly patients and patients with a history of renal impairment are at increased risk of developing these effects. In the reported cases, these reactions were generally reversible on discontinuation of treatment (see WARNINGS AND PRECAUTIONS and ADVERSE REACTIONS, Post-Market Adverse Drug Reactions).
Clinical Trial Adverse Drug Reactions
Because clinical trials are conducted under very specific conditions the adverse reaction rates observed in the clinical trials may not reflect the rates observed in practice and should not be compared to the rates in the clinical trials of another drug. Adverse drug reaction information from clinical trials is useful for identifying drug-related adverse events and for approximating rates.
Treatment of Herpes Simplex
Short-term administration (5-10 days): The most frequent adverse reactions reported during clinical trials of treatment of genital herpes with oral ZOVIRAX® in 298 patients are listed in Table 1.
Table 1 : Adverse Reactions Reported in Clinical
Trials of Treatment of Genital Herpes with Acyclovir
|Nausea and/or Vomiting||8||2.7|
Suppression of Herpes Simplex
Long-term administration: The most frequent adverse events reported in a clinical trial for the prevention of recurrences with continuous administration of 400 mg (two 200 mg capsules) 2 times daily are listed in Table 2.
Table 2 : Adverse Reactions Reported in a Clinical
Trial for the Prevention of Recurrences of Genital Herpes with Acyclovir
|Adverse Reactions||1st Year
Evidence so far from clinical trials suggests that the severity and frequency of adverse events is unlikely to necessitate discontinuation of therapy.
The most frequent adverse reactions reported during three clinical trials of treatment of herpes zoster (shingles) with 800 mg of oral ZOVIRAX® 5 times daily for 7 or 10 days or placebo are listed in Table 3.
Table 3 : Adverse Reactions Reported in Clinical
Trials of Treatment of Herpes Zoster
The most frequent adverse events reported during three clinical trials of treatment of chickenpox with oral ZOVIRAX® or placebo are listed in Table 4.
Table 4 : Adverse Reactions Reported in Clinical
Trials of Treatment of Chickenpox
Less Common Clinical Trial Adverse Drug Reactions ( < 1%)
Other adverse reactions reported in less than 1% of patients receiving ZOVIRAX® in any clinical trial included: abdominal pain, anorexia, constipation, dizziness, edema, fatigue, flatulence, inguinal adenopathy, insomnia, leg pain, medication taste, skin rash, sore throat, spasmodic hand movement and urticaria.
Abnormal Hematologic And Clinical Chemistry Findings
No clinically significant changes in laboratory values have been observed in clinical trials for the treatment of chickenpox and zoster, and for the treatment and suppression of genital herpes with ZOVIRAX®.
Post-Market Adverse Drug Reactions
The following events have been reported voluntarily during post-market use of ZOVIRAX® in clinical practice. These events have been chosen for inclusion due to either their seriousness, frequency of reporting, potential causal connection to ZOVIRAX® or a combination of these factors. Post-market adverse events are reported spontaneously from a population of unknown size, thus estimates of frequency cannot be made.
General: Fever, headache, pain and peripheral edema.
Nervous: Dizziness, paresthesia, agitation, confusion, tremor, ataxia, dysarthria, hallucinations, psychotic symptoms, convulsions, somnolence, encephalopathy and coma have been reported. These events are generally reversible and usually reported in patients with renal impairment, or with other predisposing factors (see WARNINGS AND PRECAUTIONS). These symptoms may be marked, particularly in older adults.
Digestive: Diarrhea, gastrointestinal distress and nausea.
Hematogical and Lymphatic: Anaemia, leukopenia, lymphadenopathy and thrombocytopenia.
Hypersensitivity and Skin: Alopecia, erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis, rashes including photosensitivity, pruritus, urticaria, dyspnoea, angioedema and anaphylaxis.
Special Senses: Visual abnormalities.
Urogenital: Elevated blood creatinine and blood urea nitrogen (BUN). Acute renal failure, renal pain and hematuria have been reported. Renal pain may be associated with renal failure (see WARNINGS AND PRECAUTIONS).
Read the entire FDA prescribing information for Zovirax (Acyclovir)
Additional Zovirax Information
Zovirax - User Reviews
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Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
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