PPT_Chapter_37.ppt - Antiviral Antiretroviral and Antifungal Drugs Chapter 37 Copyright \u00a9 2013 Wolters Kluwer Health | Lippincott Williams Wilkins

PPT_Chapter_37.ppt - Antiviral Antiretroviral and...

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Unformatted text preview: Antiviral, Antiretroviral, and Antifungal Drugs Chapter 37 Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Virus More than 200 viruses have been identified Acute viruses have a rapid onset and quick recovery Example: common cold Chronic viruses have recurrent episodes of exacerbations and remissions Example: acquired immunodeficiency syndrome (AIDS) Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Virus Cytomegalovirus (CMV) Virus of the herpes family Healthy individuals may have no symptoms Immunocompromised patients may have the infection Symptoms: malaise, fever, pneumonia, superinfection Can infect the eye and cause retinitis Symptoms: blurred vision, decreased visual acuity May be irreversible and can lead to blindness if untreated Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Virus • Hepatitis – Means inflammation of the liver – Group of viral infections that attack the liver – Five types: most common are A, B, and C • A – transmitted from fecal to oral route • B – transmitted via blood or body fluids • C – chronic bloodborne infection • D – transmitted via skin with contaminated blood • E – ingestion of fecal matter – Viral hepatitis is the most common reason a patient would need a liver transplantation Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Virus Herpes simplex virus (HSV) Two types: HSV-1: oral, ocular, or facial infections HSV-2: genital infections Painful vesicular lesions Lesions usually heal within 2 weeks A severe systemic disease may develop in immunosuppressed patients Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Virus Herpes zoster (shingles) Caused by varicella (chicken-pox) virus Highly contagious Causes chicken-pox in children and is easily spread via the respiratory system Recovery from childhood infection leaves the virus lying dormant in the nerve cells Virus becomes reactivated later in life Lesions appear as pustules along a sensory nerve route Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Virus Influenza Commonly called the flu Acute respiratory illness caused by influenza viruses A and B Symptoms: fever, cough, sore throat, runny or stuffy nose, headache, muscle aches, extreme fatigue Most people recover in 1–2 weeks Severe complications include pneumonia Virus changes over time Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Virus Respiratory syncytial virus (RSV) Highly contagious Infects mostly children, causing bronchiolitis and pneumonia Children younger than 6 months are the most severely affected In adults, RSV causes colds and bronchitis with fever, cough, and nasal congestion Immunocompromised patients can have severe and sometimes fatal consequences Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Actions of Antiviral Drugs Viruses can only reproduce within a living cell A virus consists of either DNA or RNA surrounded by a protein shell Antivirals act by inhibiting viral DNA or RNA replication in the virus, causing viral death Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Uses of Antiviral Drugs Initial and recurrent mucosal and cutaneous herpes simplex virus 1 and 2 infections in immunocompromised patients, encephalitis, and herpes zoster Human immunodeficiency virus Cytomegalovirus retinitis Genital herpes Influenza A respiratory tract illness Respiratory syncytial virus Viral herpes infections Hepatitis Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Adverse Reactions of Antiviral Drugs Rapid IV administration can cause crystals in the urine When administered systemically, can cause GI disturbances When administered topically, can cause burning, stinging, and pruritus at the application site Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Adverse Reactions of Antiviral Drugs Acyclovir Used orally, topically, and parenterally IV: phlebitis, lethargy, confusion, tremors, skin rashes, nausea, crystalluria Oral: nausea vomiting, diarrhea, headache, dizziness, skin rashes Topical: burning, stinging, pruritus Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Adverse Reactions of Antiviral Drugs Amantadine GI upset with nausea and vomiting Anorexia Asthenia Constipation Depression and psychosis Visual disturbances Urinary retention Orthostatic hypotension Monitor for drowsiness, dizziness, light-headedness, mood changes Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Adverse Reactions of Antiviral Drugs Oseltamivir Adults: fatigue, headache, diarrhea, nausea, vomiting Children: abdominal pain, diarrhea, vomiting, otitis media Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Adverse Reactions of Antiviral Drugs Ribavirin By inhalation: worsening of respiratory status, bacterial pneumonia, bradycardia Orally: hemolytic anemia, psychiatric reactions, GI disorders, flu-like syndrome Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Adverse Reactions of Antiviral Drugs Valacyclovir Headache, abdominal pain, nausea Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Adverse Reactions of Antiviral Drugs Zanamivir Headache, fatigue, malaise, cough Nasal signs and symptoms Throat or tonsil discomfort Risk is higher in patients with asthma or chronic obstructive pulmonary disease Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Contraindications, Precautions, and Interactions of Antiviral Drugs Contraindications: Hypersensitivity, congestive heart failure, seizures, renal disease Precautions: Renal impairment, children Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Contraindications, Precautions, and Interactions of Antiviral Drugs Acyclovir Precautions: preexisting neurologic, kidney, liver, respiratory, or fluid and electrolyte abnormalities; history of seizures; lactation Interactions: zidovudine, nephrotoxic drugs, amphotericin B, probenecid Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Contraindications, Precautions, and Interactions of Antiviral Drugs Amantadine Precautions: seizure disorders, psychiatric problems, kidney impairment, cardiac disease, lactation Interactions: antihistamines, phenothiazines, tricyclic antidepressants, disopyramide, quinidine Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Contraindications, Precautions, and Interactions of Antiviral Drugs Oseltamivir Contraindications: hypersensitivity, children less than 1 year old, immunocompromised patients Only effective for the influenza viruses, type A and B Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Contraindications, Precautions, and Interactions of Antiviral Drugs Ribavirin Contraindications: pregnancy, chronic obstructive pulmonary disease, lactation Interactions: zidovudine, digitalis Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Contraindications, Precautions, and Interactions of Antiviral Drugs Valacyclovir Contraindications: hypersensitivity to valacyclovir and acyclovir, immunocompromised Precautions: lactation Doses should be adjusted in the elderly and in patients with renal function impairment Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Contraindications, Precautions, and Interactions of Antiviral Drugs Zanamivir Precautions: pregnancy, lactation, asthma, chronic obstructive pulmonary disease, underlying respiratory diseases, patients who are allergic or intolerant to lactose Interactions: none Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Patient Management Issues with Antiviral Drugs • Evaluate patient’s general state of health and resistance to infection before therapy • Antivirals may cause anorexia, nausea, or vomiting – May tolerate small, frequent meals with soft, nonirritating foods if nausea is mild – Frequent sips of carbonated beverages or hot tea may be helpful – If severe, contact health care provider • Monitor skin lesions – Contact health care provider if no improvement or worsen Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Patient Management Issues with Antiviral Drugs Wear gloves for topical application of antiviral drugs Report any rashes Vital signs may need regular monitoring If fatigue, patient may need help walking or with activities of daily living If immunosuppressed, patients are at increased risk for infection Protect for individuals who are ill Good handwashing technique for caregivers Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Patient Management Issues with Antiviral Drugs Acyclovir Begin as soon as symptoms of herpes simplex appear May be given topically, orally, or IV Oral: without regard to meals If GI upset, take with food Monitor patients with CHF Neurologic symptoms may occur Use a glove or finger cot to apply topically Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Patient Management Issues with Antiviral Drugs Amantadine Used for prevention or treatment of respiratory tract illness caused by influenza A virus Some patients are prescribed this drug to manage extrapyramidal effects caused by drugs used to treat parkinsonism Protect capsules from moisture Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Patient Management Issues with Antiviral Drugs Oseltamivir Initiate therapy as soon as possible after flu symptoms appear, but within 2 days If used prophylactically, initiate within 2 days of exposure Not a substitute for the annual flu vaccination Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Patient Management Issues with Antiviral Drugs Ribavirin Taken by inhalation using a small-particle aerosol generator Also available as capsules taken by mouth Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Patient Management Issues with Antiviral Drugs Valacyclovir Therapy should be initiated as soon as possible after onset of the herpes zoster rash or the tingling of the herpes labialis sore Not a cure for genital herpes Take measures to prevent spreading the herpes virus Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Patient Management Issues with Antiviral Drugs Zanamivir Powder blister for inhalation Start within 2 days of onset of flu symptoms Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Educating the Patient and Family About Antiviral Drugs Patient is instructed to take the medication exactly as prescribed and to finish the complete regimen If miss a dose, take as soon as remember but do not double dose All adverse reactions should be reported to the health care provider Must understand that drugs do not cure viral infections, but should decrease symptoms and increase feelings of well-being Report any signs of infection Educate on the signs of pancreatitis Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Educating the Patient and Family About Antiviral Drugs Acyclovir Not a cure, but will shorten course and promote healing Will not prevent spread of disease to others Apply exactly as prescribed Apply using a finger cot or gloves Do not have sexual contact while lesions are present Notify health care provider if: burning, stinging or itching, rash worsens or becomes more pronounced Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Educating the Patient and Family About Antiviral Drugs Amantadine Do not drive a car or perform work that requires mental alertness until effect of drug is apparent Rise slowly from a prone to sitting position Report changes such as: nervousness, tremors, slurred speech, depression Mark calendar if on an alternate dosage schedule Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Educating the Patient and Family About Antiviral Drugs Oseltamivir Take as soon as possible after onset of flu symptoms Oral suspension should be stored in the refrigerator and is good for 10 days after reconstitution Shake before pouring Take with or without food Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Educating the Patient and Family About Antiviral Drugs Ribavirin Taken through an SPAC Report worsening of respiratory function, dizziness, confusion, shortness of breath Pregnancy category X Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Educating the Patient and Family About Antiviral Drugs Valacyclovir Not a cure for herpes simplex Will shorten course of disease and promote healing of lesions Will not prevent spread to others Do not have sexual contact when lesions are present Notify health care provider if: burning, stinging or itching, rash worsens or becomes more pronounced Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Educating the Patient and Family About Antiviral Drugs Zanamivir Take every 12 hours for 5 days Use a Diskhaler delivery system Use bronchodilator first if use a bronchodilator and it is prescribed at the same time May cause dizziness Caution operating dangerous machinery or driving an automobile Does not decrease the risk of transmission to others Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Complementary and Alternative Medicine Lemon balm When used topically, has antiviral activity against herpes simplex virus No adverse reactions with topical use Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Antiretroviral Drugs • Human immunodeficiency virus (HIV) – Causes AIDS – Type of viral infection transmitted through an infected person’s bodily secretions causing the body to develop opportunistic infections Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Antiretroviral Drugs Categories: Cellular chemokine receptor antagonists: maraviroc Fusion inhibitors (FIs): enfuvirtide Integrase inhibitors: raltegravir Nonnucleoside reverse transcriptase inhibitors (NNRTIs): delavirdine, efavirenz, etravirine, nevirapine Nucleoside/nucleotide analog reverse transcriptase inhibitors (NRTIs): abacavir, didanosine, emtricitabine, lamivudine, stavudine, telbivudine, tenofovir, zidovudine Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Antiretroviral Drugs Categories: Protease inhibitors (PIs): atazanavir, darunavir, fosamprenavir, indinavir, nelfinavir, ritonavir, saquinavir, tipranavir Combination products Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Actions of Antiretroviral Drugs Cellular chemokine receptor antagonists (CCR5 antagonists) Bind to the human chemokine receptor CCR5 on the cell membrane and prevent an interaction that is necessary for the HIV virus to enter the cell Fusion inhibitors Prevent the HIV virus from entering cells by inhibiting the fusion of the viral membrane with the cellular membrane Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Actions of Antiretroviral Drugs Integrase strand transfer inhibitors (INSTIs) Prevent the activity of an HIV enzyme that is essential for viral replication Prevent the HIV DNA from being inserted into the host cell, which prevents the formation of the HIV provirus and prevents the virus from propagating Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Actions of Antiretroviral Drugs Nonnucleoside reverse transcriptase inhibitors (NRTIs) Bind to reverse transcriptase and block its actions, which prevents the RNA-dependent and DNA-dependent polymerase activities necessary for viral replications NNRTIs Inhibit the reverse transcriptase enzyme, which inhibits viral DNA growth Protease inhibitors Block the protease enzyme that is involved in the later stages of viral replication Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Uses of Antiretroviral Drugs Decrease morbidity and mortality associated with HIV by preventing viral replication, also referred to as viral load Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Adverse Reactions of Antiretroviral Drugs Cellular chemokine receptor antagonists Maraviroc: hepatotoxicity, abdominal pain, cough, dizziness, musculoskeletal disorders, pyrexia, rash, upper respiratory tract infection, orthostatic hypotension Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Adverse Reactions of Antiretroviral Drugs Fusion inhibitors Enfuvirtide: local injection site reactions, increased bacterial pneumonia, hypersensitivity reactions Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Adverse Reactions of Antiretroviral Drugs Integrase inhibitors Raltegravir: diarrhea, headache, nausea, pyrexia, muscle weakness, rhabdomyolysis Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Adverse Reactions of Antiretroviral Drugs Nonnucleoside reverse transcriptase inhibitors Rash, increased liver enzymes Etravirine and nevirapine: Stevens-Johnson syndrome Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Adverse Reactions of Antiretroviral Drugs Nucleoside/nucleotide analog reverse transcriptase inhibitors Variety of different adverse reactions that are specific to the drug Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Adverse Reactions of Antiretroviral Drugs Protease inhibitors Hyperglycemia, fat maldistribution, serum transaminase elevations, hyperlipidemia Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Contraindications, Precautions, and Interactions of Antiretroviral Drugs Cellular chemokine receptor antagonists (maraviroc) Contraindications: severe renal impairment; patient with renal impairment who are taking CYP3A inhibitors or inducers Precautions: hepatitis, increased liver enzymes, patients with an increased risk of cardiovascular effects, lactation, impaired renal function Interactions: drugs that induce or inhibit CYP3A Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Contraindications, Precautions, and Interactions of Antiretroviral Drugs Fusion inhibitors (enfuvirtide) Contraindications: hypersensitivity Precautions: lactation Interactions: does not interact with other antiretrovirals Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Contraindications, Precautions, and Interactions of Antiretroviral Drugs Integrase inhibitors Contraindications: lactation Interactions: Raltegravir: atazanavir, atazanavir/ritonavir, omeprazole, efavirenz, etravirine, rifampin, tipranavir/ritonavir Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Contraindications, Precautions, and Interactions of Antiretroviral Drugs Nonnucleoside reverse transcriptase inhibitors Contraindications: hypersensitivity Precautions: lactation Interactions: Delavirdine: anticonvulsants, rifabutin, rifampin, ergot derivatives, HMG-CoA reductase inhibitors, pimozide, sedative/hypnotics Efavirenz, nevirapine, rilpivirine: drugs that are metabolized by CYP3A4 May cause hepatotoxicity, fat redistribution, or accumulation of body fat Have potential for severe and possibly life-threatening skin reactions Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Contraindications, Precautions, and Interactions of Antiretroviral Drugs Nucleoside/nucleotide analog reverse transcriptase inhibitors Contraindications: hypersensitivity Abacavir: hepatic impairment Precautions: lactation Zidovudine: patients with bone marrow compromise May cause redistribution or accumulation of body fat, lactic acidosis, hepatomegaly with steatosis Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins Contraindications, Precautions, and Interactions of Antiretroviral Drugs Nucleoside/nucleotide analog reverse transcriptase inhibitors...
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