Acyclovir
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acyclovir (acycloguanosine) (ay sye' kloe ver) Alti-Acyclovir (CAN), Avirax (CAN), Zovirax Pregnancy Category B Drug class
Antiviral Therapeutic actions
Antiviral activity; inhibits viral DNA replication. Indications
• • • • • • •
Initial and recurrent mucosal and cutaneous HSV 1 and 2 and varicella zoster infections in immunocompromised patients Severe initial and recurrent genital herpes infections in selected patients Herpes simplex encephalitis in patients > 6 mo Acute treatment of herpes zoster (shingles) and chickenpox Ointment: Initial HSV genital infections; limited mucocutaneous HSV infections in immunocompromised patients Cream: Recurrent herpes labialis (cold sores) in patients > 12 yr Unlabeled uses: Cytomegalovirus and HSV infection following transplant, herpes simplex infections, varicella pneumonia, disseminated primary eczema herpeticum
Contraindications and cautions
• •
Contraindicated with allergy to acyclovir, seizures, CHF, renal disease, lactation. Use cautiously with pregnancy.
Available forms
Tablets—400, 800 mg; capsules—200 mg; suspension—200 mg/5 mL; powder for injection—500 mg/vial, 1,000 mg/vial; injection—50 mg/mL; ointment—50 mg/g Dosages ADULTS Parenteral
5–10 mg/kg infused IV over 1 hr, q 8 hr (15 mg/kg/day) for 7 days. Oral
• • • •
Initial genital herpes: 200 mg q 4 hr while awake (1,000 mg/day) for 10 days. Long-term suppressive therapy: 400 mg bid for up to 12 mo. Acute herpes zoster: 800 mg q 4 hr for 7–10 days. Chickenpox: 800 mg qid for 5 days.
PEDIATRIC PATIENTS Parenteral
•
< 12 yr: 250–500 mg/m2 infused IV over 1 hr, q 8 hr (750 mg/m2/day) for 7 days.
•
> 12 yr: adult dosage.
Oral
• • •
< 2 yr: Safety not established. > 2 yr: 20 mg/kg per dose qid (80 mg/kg/day) for 5 days. > 40 kg: Use adult dosage.
GERIATRIC PATIENTS OR PATIENTS WITH RENAL IMPAIRMENT Oral
For creatinine clearance < 10 mL/min, 200 mg q 12 hr. IV Creatinine Clearance (mL/min) > 50 25–50 10–25 0–10
Dosage (IV) 5 mg/kg q 8 hr 5 mg/kg q 12 hr 5 mg/kg daily 2.5 mg/kg daily
Topical
Ointment (all ages): Apply sufficient quantity to cover all lesions 6 times/day (q 3 hr) for 7 days; 1.25-cm (0.5-in) ribbon of ointment covers 2.5 cm2 (4 in2) surface area. Cream (> 12 yr): Apply sufficient quantity to cover all lesions 5 times/day for 4 days. Pharmacokinetics Route Oral IV Topical
Onset Varies Immediate Absorption is minimal
Peak 1.5–2 hr 1 hr
Duration 8 hr
Metabolism: T1/2: 2.5–5 hr Distribution: Crosses placenta; enters breast milk Excretion: Unchanged in urine IV facts
Preparation: Reconstitute 500 mg vial in 10 mL sterile water for injection or bacteriostatic water for injection containing benzyl alcohol, 1,000 mg vial in 20 mL; concentration will be 50 mg/mL. Do not dilute drug with bacteriostatic water containing parabens. Use reconstituted solution within 12 hr; dilute IV solution to concentration of 7 mg/mL or less. Do not use biologic or colloidal fluids such as blood products or protein solutions. Warm drug to room temperature to dissolve precipitates formed during refrigeration. Infusion: Administer by slow IV infusion of parenteral solutions; avoid bolus or rapid injection. Infuse over at least 1 hr to avoid renal damage. Incompatibilities: Do not mix with diltiazem, dobutamine, dopamine, fludarabine, foscarnet, idarubicin, meperidine, morphine, ondansetron, piperacillin, sargramostim, vinorelbine. Adverse effects Systemic administration
•
CNS: Headache, vertigo, depression, tremors, encephalopathic changes
• • •
Dermatologic: Inflammation or phlebitis at injection sites, rash, hair loss GI: Nausea, vomiting, diarrhea, anorexia GU: Crystalluria with rapid IV administration, hematuria
Topical administration
•
Dermatologic: Transient burning at site of application
Interactions Systemic administration
Drug-drug • Increased effects with probenecid • Increased nephrotoxicity with other nephrotoxic drugs • Extreme drowsiness with zidovudine Nursing considerations Assessment
• •
History: Allergy to acyclovir, seizures, CHF, renal disease, lactation, pregnancy Physical: Skin color, lesions; orientation; BP, P, auscultation, perfusion, edema; R, adventitious sounds; urinary output; BUN, creatinine clearance
Interventions Systemic administration
•
Ensure that the patient is well hydrated.
Topical administration
• •
Start treatment as soon as possible after onset of signs and symptoms. Wear a rubber glove or finger cot when applying drug.
Teaching points Systemic administration
• • • • •
Complete the full course of oral therapy, and do not exceed the prescribed dose. Oral acyclovir is not a cure for your disease but should make you feel better. Avoid sexual intercourse while visible lesions are present. These side effects may occur: Nausea, vomiting, loss of appetite, diarrhea; headache, dizziness. Report difficulty urinating, rash, increased severity or frequency of recurrences.
Topical administration
• • • •
Wear rubber gloves or finger cots when applying the drug to prevent autoinoculation of other sites and transmission to others. This drug does not cure the disease; application during symptom-free periods will not prevent recurrences. Avoid sexual intercourse while visible lesions are present. This drug may cause burning, stinging, itching, rash; notify your physician if these are pronounced.
Adverse effects in Italic are most common; those in Bold are life-threatening.
Antiviral Therapeutic actions
Antiviral activity; inhibits viral DNA replication. Indications
• • • • • • •
Initial and recurrent mucosal and cutaneous HSV 1 and 2 and varicella zoster infections in immunocompromised patients Severe initial and recurrent genital herpes infections in selected patients Herpes simplex encephalitis in patients > 6 mo Acute treatment of herpes zoster (shingles) and chickenpox Ointment: Initial HSV genital infections; limited mucocutaneous HSV infections in immunocompromised patients Cream: Recurrent herpes labialis (cold sores) in patients > 12 yr Unlabeled uses: Cytomegalovirus and HSV infection following transplant, herpes simplex infections, varicella pneumonia, disseminated primary eczema herpeticum
Contraindications and cautions
• •
Contraindicated with allergy to acyclovir, seizures, CHF, renal disease, lactation. Use cautiously with pregnancy.
Available forms
Tablets—400, 800 mg; capsules—200 mg; suspension—200 mg/5 mL; powder for injection—500 mg/vial, 1,000 mg/vial; injection—50 mg/mL; ointment—50 mg/g Dosages ADULTS Parenteral
5–10 mg/kg infused IV over 1 hr, q 8 hr (15 mg/kg/day) for 7 days. Oral
• • • •
Initial genital herpes: 200 mg q 4 hr while awake (1,000 mg/day) for 10 days. Long-term suppressive therapy: 400 mg bid for up to 12 mo. Acute herpes zoster: 800 mg q 4 hr for 7–10 days. Chickenpox: 800 mg qid for 5 days.
PEDIATRIC PATIENTS Parenteral
•
< 12 yr: 250–500 mg/m2 infused IV over 1 hr, q 8 hr (750 mg/m2/day) for 7 days.
•
> 12 yr: adult dosage.
Oral
• • •
< 2 yr: Safety not established. > 2 yr: 20 mg/kg per dose qid (80 mg/kg/day) for 5 days. > 40 kg: Use adult dosage.
GERIATRIC PATIENTS OR PATIENTS WITH RENAL IMPAIRMENT Oral
For creatinine clearance < 10 mL/min, 200 mg q 12 hr. IV Creatinine Clearance (mL/min) > 50 25–50 10–25 0–10
Dosage (IV) 5 mg/kg q 8 hr 5 mg/kg q 12 hr 5 mg/kg daily 2.5 mg/kg daily
Topical
Ointment (all ages): Apply sufficient quantity to cover all lesions 6 times/day (q 3 hr) for 7 days; 1.25-cm (0.5-in) ribbon of ointment covers 2.5 cm2 (4 in2) surface area. Cream (> 12 yr): Apply sufficient quantity to cover all lesions 5 times/day for 4 days. Pharmacokinetics Route Oral IV Topical
Onset Varies Immediate Absorption is minimal
Peak 1.5–2 hr 1 hr
Duration 8 hr
Metabolism: T1/2: 2.5–5 hr Distribution: Crosses placenta; enters breast milk Excretion: Unchanged in urine IV facts
Preparation: Reconstitute 500 mg vial in 10 mL sterile water for injection or bacteriostatic water for injection containing benzyl alcohol, 1,000 mg vial in 20 mL; concentration will be 50 mg/mL. Do not dilute drug with bacteriostatic water containing parabens. Use reconstituted solution within 12 hr; dilute IV solution to concentration of 7 mg/mL or less. Do not use biologic or colloidal fluids such as blood products or protein solutions. Warm drug to room temperature to dissolve precipitates formed during refrigeration. Infusion: Administer by slow IV infusion of parenteral solutions; avoid bolus or rapid injection. Infuse over at least 1 hr to avoid renal damage. Incompatibilities: Do not mix with diltiazem, dobutamine, dopamine, fludarabine, foscarnet, idarubicin, meperidine, morphine, ondansetron, piperacillin, sargramostim, vinorelbine. Adverse effects Systemic administration
•
CNS: Headache, vertigo, depression, tremors, encephalopathic changes
• • •
Dermatologic: Inflammation or phlebitis at injection sites, rash, hair loss GI: Nausea, vomiting, diarrhea, anorexia GU: Crystalluria with rapid IV administration, hematuria
Topical administration
•
Dermatologic: Transient burning at site of application
Interactions Systemic administration
Drug-drug • Increased effects with probenecid • Increased nephrotoxicity with other nephrotoxic drugs • Extreme drowsiness with zidovudine Nursing considerations Assessment
• •
History: Allergy to acyclovir, seizures, CHF, renal disease, lactation, pregnancy Physical: Skin color, lesions; orientation; BP, P, auscultation, perfusion, edema; R, adventitious sounds; urinary output; BUN, creatinine clearance
Interventions Systemic administration
•
Ensure that the patient is well hydrated.
Topical administration
• •
Start treatment as soon as possible after onset of signs and symptoms. Wear a rubber glove or finger cot when applying drug.
Teaching points Systemic administration
• • • • •
Complete the full course of oral therapy, and do not exceed the prescribed dose. Oral acyclovir is not a cure for your disease but should make you feel better. Avoid sexual intercourse while visible lesions are present. These side effects may occur: Nausea, vomiting, loss of appetite, diarrhea; headache, dizziness. Report difficulty urinating, rash, increased severity or frequency of recurrences.
Topical administration
• • • •
Wear rubber gloves or finger cots when applying the drug to prevent autoinoculation of other sites and transmission to others. This drug does not cure the disease; application during symptom-free periods will not prevent recurrences. Avoid sexual intercourse while visible lesions are present. This drug may cause burning, stinging, itching, rash; notify your physician if these are pronounced.
Adverse effects in Italic are most common; those in Bold are life-threatening.
