acyclovir

acyclovir /acy·clo·vir/ (a-si´klo-vēr) a synthetic purine nucleoside with selective activity against herpes simplex virus; used as the base or the sodium salt in the treatment of genital and mucocutaneous herpesvirus infections.

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a·cy·clo·vir (-skl-vîr, -kl-)

n.

A synthetic purine nucleoside analog that is derived from guanine and is used in the treatment of herpes simplex, herpes zoster, and varicella zoster viral infections. Also called acycloguanosine.

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Acyclovir

An antiviral drug that is available under the trade name Zovirax, in oral, intravenous, and topical forms. The drug blocks the replication of the varicella zoster virus.

Mentioned in: Chickenpox, Shingles

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acyclovir

[əsī′klōvir]

an antiviral agent with activity against herpesvirus types 1 and 2 and varicella zoster virus. Acyclovir is converted by a herpesvirus enzyme into a molecule (acyclovir triphosphate) that inhibits the synthesis of deoxyribonucleic acid (DNA) molecules in the virally infected cells, thereby inhibiting viral replication.

indications It is prescribed topically in an ointment for the treatment of herpes simplex lesions (cold sores) and both orally and systemically (oral and IV) in other types of herpes infections, including genital herpes, herpes encephalitis, chickenpox (varicella zoster), and shingles (herpes zoster).

contraindication Known sensitivity to this drug prohibits its use.

adverse effects After topical use, irritation or pruritus may occur; after systemic use, diaphoresis, headache, and nausea may occur. When it is administered intravenously in the treatment of immunosuppressed patients, there may be pain at the site of the injection, and 1% to 10% of such patients experience acute renal failure.

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acyclovir (aˈ·sīˑ·klō·virˈ),

n antiviral medication used topically to combat herpes virus types 1 and 2 as well as the varicella zoster and other viruses.

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acyclovir (āsī´klōvir),

n brand name: Zovirax;
drug class: antiviral.
Uses: a 5% ointment; may be used systemically. Drug of choice in simple mucocutaneous herpes simplex, in immunocompromised patients with initial herpes genitalis. Active against herpes viruses such as herpes zoster and varicella (chickenpox).

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acyclovir, aciclovir

a synthetic analog of guanosine which selectively interferes with viral DNA synthesis. Used parenterally and topically as an antiviral agent in herpesvirus infections in cats, birds and horse.

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antiviral agents 

Substances which inhibit the growth of a virus (e.g. herpes) by inhibiting DNA or RNA synthesis. Common agents include aciclovir (acyclovir), idoxuridine, ganciclovir, trifluoridine (trifluorothymidine) and vidarabine. See herpetic keratitis; virus.

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acyclovir

Pharmacologic class: Acyclic purine nucleoside analogue

Therapeutic class: Antiviral

Pregnancy risk category B

Action

Inhibits viral DNA polymerase, thereby inhibiting replication of viral DNA. Specific for herpes simplex types 1 (HSV-1) and 2 (HSV-2), varicella-zoster virus, Epstein-Barr virus, and cytomegalovirus (CMV).

Availability

Capsules: 200 mg

Cream: 5% in 2-g tube

Injection: 50 mg/ml

Ointment: 5% in 15-g tube

Powder for injection: 500 mg/vial, 1,000 mg/vial

Suspension: 200 mg/5 ml

Tablets: 400 mg, 800 mg

⊘Indications and dosages

➣ Acute treatment of herpes zoster (shingles)

Adults: 800 mg P.O. q 4 hours while awake (five times/day) for 7 to 10 days

➣ Initial episode of genital herpes

Adults: 200 mg P.O. q 4 hours while awake (1,000 mg/day) for 10 days

➣ Chronic suppressive therapy for recurrent genital herpes episodes

Adults: 400 mg P.O. b.i.d., or 200 mg P.O. three to five times daily for up to 12 months

➣ Intermittent therapy for recurrent genital herpes episodes

Adults: 200 mg P.O. q 4 hours while awake (five times/day) for 5 days, initiated at first sign or symptom of recurrence

➣ Management of initial episodes of genital herpes and limited, non-life-threatening mucocutaneous herpes simplex virus infections in immunocompromised patients

Adults: Apply approximately ½" ribbon of ointment per 4 square inches of surface area to sufficiently cover all lesions q 3 hours, six times daily for 7 days.

➣ Treatment of recurrent herpes labialis (cold sores)

Adults and adolescents ages 12 and older: Apply cream to infected area five times daily for 4 days.

➣ Varicella (chickenpox)

Adults and children weighing more than 40 kg (88 lb): 800 mg P.O. q.i.d. for 5 days

Children older than age 2: 20 mg/kg P.O. q.i.d. for 5 days

➣ Mucosal and cutaneous HSV-1 and HSV-2 in immunocompromised patients

Adults and children older than age 12: 5 mg/kg I.V. infusion over 1 hour given q 8 hours for 7 days

Children younger than age 12: 10 mg/kg I.V. infusion over 1 hour given q 8 hours for 7 days

➣ Herpes simplex encephalitis

Adults and children older than age 12: 10 mg/kg I.V. over 1 hour given q 8 hours for 10 days

Children ages 3 months to 12 years: 20 mg/kg I.V. over 1 hour given q 8 hours for 10 days

Children from birth to 3 months: 10 mg/kg I.V. over 1 hour given q 8 hours for 10 days

➣ Varicella zoster infections in immunocompromised patients

Adults and adolescents older than age 12: 10 mg/kg I.V. over 1 hour given q 8 hours for 7 days

Children younger than age 12: 20 mg/kg I.V. over 1 hour given q 8 hours for 7 days

Dosage adjustment

• Renal impairment
• Obesity (adult dosage based on ideal weight)
• Elderly patients

Off-label uses

• Herpes zoster encephalitis
• CMV and HSV infection after bone marrow or kidney transplantation
• Infectious mononucleosis
• Varicella pneumonia

Contraindications

• Hypersensitivity to drug or valacyclovir

Precautions

Use cautiously in:
• preexisting serious neurologic, hepatic, pulmonary, or fluid or electrolyte abnormalities
• renal impairment
• obesity
• pregnant or breastfeeding patients.

Administration

• Make sure patient is adequately hydrated before starting therapy.
• Give single I.V. dose by infusion over at least 1 hour to minimize renal damage.
• Don't give by I.V. bolus or by I.M. or subcutaneous route.
• Be aware that absorption of topical acyclovir is minimal.

Route	Onset	Peak	Duration
P.O.	Variable	1.5-2 hr	4 hr
I.V.	Immediate	1 hr	8 hr
Topical	Unknown	Unknown	Unknown

Adverse reactions

CNS: aggressive behavior, dizziness, malaise, weakness, paresthesia, headache; with I.V. use - encephalopathic changes (lethargy, tremors, obtundation, confusion, hallucinations, agitation, seizures, coma)

CV: peripheral edema

EENT: vision abnormalities

GI: nausea, vomiting, diarrhea

GU: proteinuria, hematuria, crystalluria, vaginitis, candidiasis, changes in menses, vulvitis, oliguria, renal failure, glomerulonephritis

Hematologic: anemia, lymphadenopathy, thrombocytopenia, thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (in immunocompromised patients), disseminated intravascular coagulation, hemolysis, leukopenia, leukoclastic vasculitis

Hepatic: jaundice, hepatitis

Musculoskeletal: myalgia

Skin: photosensitivity rash, pruritus, angioedema, alopecia, urticaria, severe local inflammatory reactions (with I.V. extravasation), toxic epidermal necrolysis, erythema multiforme

Other: gingival hyperplasia, fever, excessive thirst, pain at injection site, anaphylaxis, Stevens-Johnson syndrome

Interactions

Drug-drug. Interferon: additive effect

Nephrotoxic drugs: increased risk of nephrotoxicity

Probenecid: increased acyclovir blood level

Zidovudine: increased CNS effects, especially drowsiness

Drug-diagnostic tests. Alanine aminotransferase, aspartate aminotransferase, bilirubin, blood urea nitrogen: increased levels

Patient monitoring

• Monitor fluid intake and output.
• Assess for signs and symptoms of encephalopathy.
• Evaluate patient frequently for adverse reactions, especially bleeding tendency.
• Monitor CBC with white cell differential and kidney function test results.

Patient teaching

• Instruct patient to keep taking drug exactly as prescribed, even after symptoms improve.
• Advise patient to drink enough fluids to ensure adequate urinary output.
• Tell patient to monitor urine output and report significant changes.
☞ Instruct patient to immediately report unusual bleeding or bruising.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.
• Advise patient to minimize GI upset by eating small, frequent servings of food and drinking plenty of fluids.
• Tell patient to use soft toothbrush and electric razor to avoid injury to gums and skin.
• Advise patient to avoid sexual intercourse when visible herpes lesions are present.
• Inform patient that he may need to undergo regular blood testing during therapy.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.

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acyclovir

Zovirax Infectious disease A nucleoside analogue used to manage viral infections in Pts with BMTs, chemotherapy-induced or acquired immunosuppression–eg, AIDS Indications HSV-1, HSV-2, HVZ Adverse effects Upset stomach, headache, nausea; hair loss from prolonged use. Cf Foscarnet, Gancyclovir.