Chapter 7 Anti-Infectives: Antiviral Drugs PDF

Chapter 7  Chapter 7 Anti-infectives: Antiviral Drugs Understanding Pharmacology, 3rd ed. Workman Learning Objectives—Lesson 7.1 1. Explain the names, actions, usual adult dosages, possible side effects, and adverse effects of the various types of nonretro...

Chapter 7  Chapter 7 Anti-infectives: Antiviral Drugs Understanding Pharmacology, 3rd ed. Workman Learning Objectives—Lesson 7.1 1. Explain the names, actions, usual adult dosages, possible side effects, and adverse effects of the various types of nonretroviral drug therapies. Viruses Intracellular, submicroscopic parasites that must infect a living cell to reproduce Two types: Common viruses (nonretroviruses) Retroviruses Uses RNA as its genomic material Contains two complete copies of single stranded RNA Viruses are NOT capable of self-reproduction Shingles, measles, mumps, herpes, warts, hepatitis, and the common cold are all Viruses Antiviral Drug Therapy Virustatic: Reduces the number of viruses Intended responses: Shorten the duration or intensity of an existing viral disease Prevent reactivation of a dormant viral infection Prevent a viral infection from multiplying to the point of disease Allergic reactions always possible More serious reactions occur when given intravenously Teaching priorities: Antiviral drugs must be taken exactly as prescribed; must take drug long enough to work Drugs for Herpes Simplex Infections Slow viral reproduction Most effective against genital herpes infections, Epstein-Barr virus, cytomegalovirus, varicella-zoster virus Side effects: Headache, dizziness, nausea, diarrhea Adverse effects: Reduced kidney function, leading to kidney damage and failure; pain/irritation at injection site; reduced efficacy of antiseizure drugs Teaching priorities: Same as general antiviral drugs Life span considerations: Weigh benefits against risks in pregnancy; not recommended during lactation Drugs for Common Respiratory Viral Infections Baloxavir, oseltamivir, peramivir, zanamivir Side effects: Headache, nausea/vomiting, diarrhea, dizziness Adverse effects: Vary by specific drug May include acute confusion, delirium, hallucinations, elevated liver enzymes Administering Drugs for Common Respiratory Viral Infections Check before: Commonly reported adverse events Gastrointestinal: diarrhea, Ask about drug allergies nausea, vomiting, constipation Neurologic: insomnia Do not administer peramivir with other drugs Cardiovascular: hypertension Contraindicators No contraindications in Check after: manufacturer labeling Warnings and precautions For IV drugs, assess patient every 15 minutes Teaching priorities: Take drug exactly as prescribed Teach patients taking zanamivir how to use a dry powder inhaler Ribavirin Ribavirin suppresses viral action and reproduction Used for viral infections that do not respond to other antiviral agents Side effects: Nausea/vomiting, diarrhea, fever, headache, rash, conjunctivitis, muscle pain, fatigue, dizziness, runny nose, injection site pain or irritation Adverse effects: Teratogenic Prolonged use may impair functioning of liver, kidneys, heart, ears. May lead to some forms of cancer. Administering Ribavirin Check before: Hearing; cardiac, respiratory, neurologic, kidney, liver functioning Blood counts and vital signs Ask about other drugs the patient may be taking Wear a mask when giving aerosolized form Check after: Monitor closely for side effects or organ toxicity Review lab values daily Assess hearing daily Life Span Considerations for Ribavirin Pregnancy and lactation: Do not use during pregnancy or breastfeeding! Use two forms of contraception while taking the drug, and 1 month after discontinuing the drug Drugs for Chronic Hepatitis C Infection Inhibits viral proteins and enzymes important to virus replication and reproduction Side effects: Headache, GI discomfort, rashes, fatigue Adverse effects: Elevated liver enzymes, jaundice, bone marrow suppression, angioedema, drug interactions Teaching priorities: Avoid alcohol Women should use two forms of contraception Report signs of allergic reaction or jaundice Drugs for Chronic Hepatitis B Infection Limits replication and reproduction of HBV; may be used for months to years Side effects: Fatigue, headache, fever, rash, muscle aches Adverse effects: Peginterferon: Psychiatric disorders worsen, bone marrow suppression Entecavir: liver toxicity, lactic acidosis, shallow breathing Teaching priorities: Avoid alcohol; women use two forms of contraception Report new feelings of depression Report signs of allergic reaction or jaundice Life Span Considerations for Drugs for Chronic Hepatitis B Infection Pregnancy and lactation: Studies have not been performed Strong likelihood of peginterferon causing pregnancy loss Peginterferon and entecavir contraindicated during pregnancy and breastfeeding Learning Objectives—Lesson 7.2 4. Explain the names, actions, usual adult dosages, possible side effects, and adverse effects of the various types of retroviral drug therapies. 5. Describe priority actions to take before and after giving any of the different types of retroviral drug therapies. 6. Prioritize essential information to teach patients who take any of the different types of retroviral drug therapies. 7. Explain appropriate life span considerations for the various types of nonretroviral and retroviral drug therapies. Retroviruses Always use RNA as their genetic material Allow high efficiency of cellular infection Human immune deficiency virus (HIV) HIV/AIDS HIV attacks the immune system Most severe form of immune deficiency disease caused by HIV infection is acquired immune deficiency syndrome (AIDS) Everyone with AIDS has HIV infection Not everyone with HIV infection has AIDS Opportunistic infections Seven Classes of Antiretroviral Drugs  Nucleoside analog reverse transcriptase inhibitors (NRTIs)  Non-nucleoside analog reverse transcriptase inhibitors (NNRTIs)  Protease inhibitors (PIs)  Fusion inhibitors  CCR5 antagonists  Integrase strand transfer inhibitors (INSTIs)  Attachment inhibitors Multiple classes of drugs given is called a “cocktail” Antiretroviral Therapy (ART) Virustatic – stops the growth of viruses – does not kill viruses Drug resistance common; related to missed drug doses New combination therapy is easier to manage (1-3 pills per day) Be alert to allergic reactions Intended response: suppression of viral reproduction, delay progression to later stages, prevent transmission Measured by “viral load” and decreased opportunistic infections; immune function improved Common Side Effects and Adverse Effects of Combination ART Side effects: Rash, nausea, vomiting, abdominal pain, headache, fatigue, weight gain, difficulty sleeping, vivid dreams or nightmares Adverse effects: Elevated liver enzymes, jaundice, increased risk of birth defects, many interactions with other drugs Priority Actions for Combination ART Check patient for liver problems, glucose levels (if diabetic) Lifelong treatment; ensure appropriate, in-depth education Obtain a list of all drugs patient is currently taking Teaching priorities: Take drugs exactly as prescribed, be aware of signs of liver toxicity, do not change other drugs without discussing with a provider Life Span Considerations for Combination ART Pediatric considerations: Not approved for use in children Pregnancy and lactation: Not approved; HIV positive mothers are instructed not to breastfeed. Older adults: Be careful of drug interactions Drugs for Preexposure Prophylaxis of HIV Infection Prevent sexual transmission of HIV Combination drugs emtricitabine and tenofovir for HIV-1 negative patients with a partner who is HIV-1 positive Does not replace safer sex practices