Chapter 93: Antiviral Agents I: Drugs for Non-HIV Viral Infections

A patient with HIV and mucocutaneous HSV is being treated with foscarnet after failing treatment with acyclovir. After 2 weeks, the patient's dose is increased to 90 mg/kg over 2 hours from 40 mg/kg over 1 hour. The patient reports numbness in the extremities and perioral tingling. What will the nurse do? a.Notify the provider and request an order for a serum calcium level. b.Notify the provider of potential foscarnet overdose. c.Request an order for a creatinine clearance level. d.Request an order of IV saline to be given before the next dose.

ANS: A Foscarnet frequently causes hypocalcemia and other electrolyte and mineral imbalances. Paresthesias, numbness in the extremities, and perioral tingling can indicate hypocalcemia, so a calcium level should be drawn. These are not signs of foscarnet overdose. Nephrotoxicity may occur, but these are not signs of renal complications, so a creatinine clearance is not indicated. If nephrotoxicity occurs, prehydration with IV saline is indicated to reduce the risk of renal injury.

A patient has lamivudine-resistant hepatitis B and has been taking entecavir [Baraclude] for 2 years. The patient asks the nurse why the provider has recommended taking the drug for another year. What will the nurse tell the patient? a."Entecavir can reverse fibrosis and cirrhosis of the liver when taken long term." b."It is necessary to continue taking entecavir to avoid withdrawal symptoms." c."The drug will be given until the infection is completely eradicated." d."You will need to continue taking entecavir to prevent lactic acidosis and hepatotoxicity."

ANS: A Recent evidence indicates that, with long-term use (3 years), entecavir can reverse fibrosis and cirrhosis. The drug is not continued to avoid withdrawal symptoms. Patients who stop taking entecavir may experience acute exacerbations of hepatitis B; the disease is not eradicated. Entecavir can cause lactic acidosis and hepatotoxicity; it does not prevent these adverse effects.

The nurse is caring for a patient receiving intravenous acyclovir [Zovirax]. To prevent nephrotoxicity associated with intravenous acyclovir, the nurse will: a.hydrate the patient during the infusion and for 2 hours after the infusion. b.increase the patient's intake of foods rich in vitamin C. c.monitor urinary output every 30 minutes. d.provide a low-protein diet for 1 day before and 2 days after the acyclovir infusion.

ANS: A The nurse should ensure that the patient is hydrated during the acyclovir infusion and for 2 hours after the infusion to prevent nephrotoxicity. Increasing vitamin C would not help prevent nephrotoxicity. Monitoring urine output is important but would not help prevent nephrotoxicity. A low-protein diet is not indicated after an acyclovir infusion.

A patient comes to the clinic and receives valacyclovir [Valtrex] for a herpes-zoster virus. The nurse instructs the patient to take the medication: a.without regard to meals. b.without any dairy products. c.each morning. d.on an empty stomach.

ANS: A The patient may take the medication without regard to meals. The patient does not need to avoid dairy products, take the pill only in the morning, or take it on an empty stomach.

A male patient with hepatitis C will begin triple drug therapy with pegylated interferon alfa 2a [Pegasys], ribavirin [Ribasphere], and boceprevir [Victrelis]. The patient tells the nurse that his wife is pregnant. What will the nurse tell him? a.Boceprevir is contraindicated in males whose partners are pregnant. b.He should use a barrier contraceptive when having sex. c.He should use dual drug therapy with pegylated interferon alfa and ribavirin only. d.This combination drug therapy is safe for him to use.

ANS: A The triple combination is dangerous for pregnant women whose partners are using it, so it is contraindicated for any man whose partner is pregnant. Barrier contraceptives should be used by couples to prevent pregnancy when either partner is taking the triple combination therapy. Ribavirin is teratogenic and is not safe when a partner is pregnant. This combination is not safe for pregnant women whose partners are taking these drugs.

A patient with hepatitis B begins treatment with adefovir [Hepsera] and asks the nurse how long the drug therapy will last. The nurse will tell the patient that the medication will need to be taken for: a.a lifetime. b.an indefinite, prolonged period of time. c.48 weeks. d.until nephrotoxicity occurs

ANS: B Current guidelines recommend treatment only for patients at highest risk; it is unknown whether treatment should continue lifelong. Treatment is usually prolonged, without a specific period of time. Nephrotoxicity is common but is not the deciding factor when determining length of effective treatment.

A patient has a positive test for hepatitis C and is admitted to the hospital. The admission laboratory tests reveal a normal ALT, and a liver biopsy is negative for hepatic fibrosis and inflammation. The nurse will prepare this patient for: a.dual therapy with pegylated interferon alfa and ribavirin. b.no medication therapy at this time. c.pegylated interferon alfa only until ALT levels are elevated. d.triple drug therapy with pegylated interferon alfa, ribavirin, and boceprevir.

ANS: B Current recommendations are that treatment is used only for patients with HCV viremia, persistent elevation of ALT, and evidence of hepatic fibrosis and inflammation upon liver biopsy. Dual therapy has been the regimen of choice for patients with the above symptoms, but the addition of a protease inhibitor has been shown to improve outcomes. It is not correct to give pegylated interferon alfa until ALT levels are elevated. Triple drug therapy is used for patients with the above symptoms.

A patient with HIV contracts herpes simplex virus (HSV), and the prescriber orders acyclovir [Zovirax] 400 mg PO twice daily for 10 days. After 7 days of therapy, the patient reports having an increased number of lesions. The nurse will expect the provider to: a.extend this patient's drug therapy to twice daily for 12 months. b.give intravenous foscarnet every 8 hours for 2 to 3 weeks. c.increase the acyclovir dose to 800 mg PO 5 times daily. d.order intravenous valacyclovir [Valtrex] 1 gm PO twice daily for 10 days

ANS: B Foscarnet is active against all known herpesviruses and is used in immunocompromised patients with acyclovir-resistant HSV or VZV. This patient is demonstrating resistance to acyclovir, so extending acyclovir therapy or increasing the acyclovir dose will not be effective. Valacyclovir is not approved for use in immunocompromised patients because of the risk for thrombotic thrombocytopenic purpura/hemolytic uremic syndrome

A nurse is teaching a group of nursing students about influenza prevention. Which statement by a student indicates understanding of the teaching? a."I may develop a mild case of influenza if I receive the vaccine by injection." b."I should receive the vaccine every year in October or November." c."If I have a cold I should postpone getting the vaccine." d."The antiviral medications are as effective as the flu vaccine for preventing the flu."

ANS: B Influenza vaccine should be given every year in October or November. The vaccine will not cause influenza. Minor illnesses, such as a cold, are not a contraindication for receiving the vaccine. Antiviral medications are not as effective as the flu vaccine in preventing influenza.

A patient has a positive test for influenza type A and tells the nurse that symptoms began 5 days before being tested. The prescriber has ordered oseltamivir [Tamiflu]. The nurse will tell the patient that oseltamivir: a.may decrease symptom duration by 2 or 3 days. b.may not be effective because of the delay in starting treatment. c.may reduce the severity but not the duration of symptoms. d.will alleviate symptoms within 24 hours of the start of therapy.

ANS: B Oseltamivir is most effective when begun within 2 days after symptom onset. When started within 12 hours of symptom onset, it may decrease duration of symptoms by 2 to 3 days. The drug reduces both symptom severity and symptom duration when used in a timely fashion. It does not rapidly alleviate symptoms.

A nurse provides teaching for a patient with cytomegalovirus (CMV) retinitis who will receive the ganciclovir ocular implant [Vitrasert]. Which statement by the patient indicates a need for further teaching? a."My vision may be blurred for 2 to 4 weeks after receiving the implant." b."Surgical placement of the implant is an outpatient procedure." c."The implant will remain in place permanently." d."The implant will slow progression of CMV retinitis."

ANS: C Ganciclovir ocular implants must be replaced every 5 to 8 months and do not remain in place permanently. It is correct that vision may be blurred for 2 to 4 weeks after placement of the implant, that placement is an outpatient procedure, and that the implant will slow progression of CMV retinitis.

A patient who is pregnant has a history of recurrent genital herpesvirus (HSV). The patient asks the nurse what will be done to suppress an outbreak when she is near term. The nurse will tell the patient that: a.antiviral medications are not safe during pregnancy. b.intravenous antiviral agents will be used if an outbreak occurs. c.oral acyclovir [Zovirax] may be used during pregnancy. d.topical acyclovir [Zovirax] must be used to control outbreaks.

ANS: C Oral acyclovir is devoid of serious adverse effects and may be used safely during pregnancy. It is incorrect to tell this patient that antiviral medications are not safe during pregnancy. Oral acyclovir is used to suppress recurrent genital herpes near term; intravenous antiviral medications are not indicated. It is not necessary to rely on topical medications because oral acyclovir is safe.

A nursing student asks a nurse why pegylated interferon alfa is used instead of regular interferon for a patient with hepatitis C. The nurse will tell the student that pegylated interferon: a.decreases the need for additional medications. b.has fewer adverse effects than interferon. c.is administered less frequently than interferon. d.may be given orally to increase ease of use.

ANS: C Pegylated interferon alfa preparations are preferred because of their convenience and superior efficacy. These preparations may be given once weekly instead of three or more times per week like the regular interferon. Using pegylated interferons does not decrease the need for additional medications. Pegylated interferons have similar adverse effects. Pegylated interferons are not given orally.

An immunocompromised child is exposed to chickenpox and the provider orders valacyclovir [Valtrex] to be given orally three times daily. The nurse will contact the provider to change this order for which reason? a.Valacyclovir is not used as varicella prophylaxis. b.The dosage is too high for this indication. c.The drug may cause serious adverse effects in immunocompromised patients. d.Valacyclovir is not approved for use in children.

ANS: C Valacyclovir is approved for use for varicella in immunocompetent children. In immunocompromised patients, it has produced a syndrome known as thrombotic thrombocytopenic purpura/hemolytic uremia syndrome (TTP/HUS). The dosage is fine for immunocompetent children.

A female patient who has hepatitis C is being treated with pegylated interferon alfa and ribavirin [Ribasphere]. It will be important for the nurse to teach this patient that: a.if she gets pregnant, she should use the inhaled form of ribavirin [Virazole]. b.if she is taking oral contraceptives, she should also take a protease inhibitor. c.she should use a hormonal contraceptive to avoid pregnancy. d.she will need a monthly pregnancy test during her treatment.

ANS: D Ribavirin causes severe fetal injury and is contraindicated during pregnancy. Women taking ribavirin must rule out pregnancy before starting the drug, monthly during treatment, and monthly for 6 months after stopping treatment. Inhaled ribavirin is also embryo lethal and teratogenic. Adding a protease inhibitor will reduce the efficacy of oral contraceptives. Women using ribavirin should use two reliable forms of birth control.