Objective 4.2 Part 2 Antimicrobials EDITED 2024 STUDENT PDF

ANTIMICROBIAL DRUGS Pharmacology PN 1290 Winter 2024 Objective 4.2 Part 2 This Photo by Unknown Author is licensed under CC BY-ND Learner Objectives 4.2.1 Describe the purpose of commonly used antimicrobial agents. 4.2.2 Discuss the therapeutic and adverse effects of commonly used antimicrobial agen...

ANTIMICROBIAL DRUGS Pharmacology PN 1290 Winter 2024 Objective 4.2 Part 2 This Photo by Unknown Author is licensed under CC BY-ND Learner Objectives 4.2.1 Describe the purpose of commonly used antimicrobial agents. 4.2.2 Discuss the therapeutic and adverse effects of commonly used antimicrobial agents. 4.2.3 Discuss examples of commonly used antimicrobial agents. 4.2.4 Describe the monitoring of therapeutic levels of antimicrobials. 4.2.5 Discuss common drug interactions related to antimicrobial agents. 4.2.6 Discuss nursing interventions when administering these medications across the lifespan. ANTIVIRALS This Photo by Unknown Author is licensed under CC BY General Principles of Virology Viruses are very tiny microorganisms, smaller than bacteria. Unlike bacteria, viruses can only replicate inside the cells of their host A virus isn’t considered a cell, but instead are particles that infect and replicate inside host cells (intracellular parasites) - A mature virus particle is known as a virion Not suppressed by antibiotics, damage takes place within the cell Enters the body via 4 routes - Inhalation through respiratory tract - Ingestion via GI tract - Placenta via circulation (mom to baby) - Inoculation via skin/mucous membranes (sexual contact, blood transfusions, sharing of needles, bug bites, etc.) Viral Structure Simplest of all organisms (genome, capsid, & envelope) Genome is the inner core that is composed of single or double stranded DNA Capsid is the protein coat that surrounds and protects the genome Envelope is the outer most layer of the virion (not present in all viruses) aids in fusion to hosts cells Body’s Defense Mechanisms Viral Illnesses Smallpox (poxviruses) Sore throat and conjunctivitis (adenoviruses) Warts (papovaviruses) Influenza (orthomyxoviruses) Respiratory infections (coronaviruses, rhinoviruses) Gastroenteritis (rotaviruses, Norwalk-like viruses) HIV/AIDS (retroviruses) Herpes (herpesviruses) Hepatitis (hepadnaviruses) Herpes Simplex Virus HSV-1 is oral herpes (cold sores) – most common HSV-2 is genital herpes Both are highly transmissible through close physical contact Painful skin lesions with periods of dormancy vs. acute outbreaks Antivirals do not cure, but can speed up the process of remission and reduce the duration of painful symptoms Can be life threatening in immunocompromised individuals and neonates Varicella-Zoster Virus Causes chicken pox (varicella) and shingles (zoster) Chicken pox or varicella is highly contagious with transmission occurring from weeping lesions or droplet inhalation; usually non invasive but can become complicated if Reye’s syndrome (condition causing fatty liver and encephalopathy) develops as a result; usually only treat when immunocompromised; vaccine helps maintain prevalence Zoster or shingles is caused by the reactivation of VZV from its dormant state; lesions appear along dermatomes (nerve tracts); very painful; treated with acyclovir which will work best if started within 72 hours of symptom onset Antivirals Antiviral drugs are chemicals that kill or supress viruses by either destroying virions or inhibiting their ability to replicate – the body’s immune system can control/eliminate a viral infection when the ability to replicate is suppressed The best responses to antiviral drugs are most commonly seen in those with competent immune systems Immunocompromised patients are susceptible to opportunistic infections Commonly used drugs are disinfectants and immunoglobulins Disinfectants are virucides that are used to disinfect medical equipment, as well as parts of the body during invasive procedures (povidone-iodine / Ovadine) Immunoglobulins are concentrated antibodies that can attack and destroy viruses. Although these can be considered antiviral drugs, they are more commonly thought of as immunizing drugs Antiretroviral Drugs* Antivirals (Non HIV) MOA: Interferes with the ability of the virus to carry out its reproductive functions, hence reducing replication. Stops the virus from growing, but cannot kill it. Lowers viral concentration to allow for elimination of virus by the patient immune system. Does not cure, but may lessen symptoms Indications: Table 45.1 pg. 736 Treat a variety of common conditions caused by different viruses (HSV 1&2, varicella, and some influenza infections) Examples: Zovirax (acyclovir), Abreva, Virazole (ribavirin), Tamiflu (oseltamivir) Table 45.1 Antivirals (Non HIV) Contraindications: Severe Allergy & some contraindications specific to certain antivirals Interactions: Table 45.3 pg. 737 Many drug interactions Nursing Implications: Wear gloves when applying topical applications Provide symptomatic relief Monitor skin lesions for improvement Educate; symptom management (itch/painkillers), proper storage and application, prophylaxis (safe sex practices) Adverse Effects: Antivirals (Non HIV) Few, generally well tolerated Rapid resistance to medication Can lower immune response resulting in more serious toxicities Will vary depending on medication chosen Table 45.2 pg. 737 Antivirals: Nursing Implications Before beginning therapy, thoroughly assess underlying disease and medical history, including allergies. Assess baseline vital signs and nutritional status. Assess for contraindications, conditions that may indicate cautious use, and potential drug interactions. Be sure to teach proper technique for applying ointments, aerosol powders, and so on. Emphasize handwashing before and after administration of medications, to prevent site contamination and spread of infection. Instruct patients to wear a glove or finger cot when applying ointments or solutions to affected areas. Antivirals: Nursing Implications Instruct patients to consult their prescribers before taking any other medication, including over-the-counter medications. Emphasize the importance of good hygiene. Inform patients that antiviral medications are not cures but do help to manage symptoms. Instruct patients on the importance of taking these medications exactly as prescribed and for the full course of treatment. Instruct patients to start therapy with antiviral medications at the earliest sign of recurrent episodes of genital herpes or herpes zoster. ANTITUBERCULAR This Photo by Unknown Author is licensed under CC BY Tuberculosis (TB) Medical diagnosis of any infectious disease caused by the bacterial species known as Mycobacterium tyberculosis. Most commonly characterized by granulomas in the lungs (caused by M.tuberculosis) Other mycobacterial species such as M.leprae (causes leprosy), M.aviumintracellulare (similar to TB, but has GI symptoms) MTB is an aerobic bacillus (requiring O2/rod shaped microorganism) S/S: Cough productive for blood & lasting longer than two weeks, weight loss, chest pain, fatigue, weakness, fever, nights sweats, chills. Difficult to kill because it is a slow growing organism, disrupting metabolism is difficult Antitubercular Drugs Two categories: First-Line & Second-Line antitubercular drugs First line drugs are tried first, and secondary drugs are reserved for more complicated infections (Table 46.2 pg. 755) Two - three effective drugs must be given at all times. Given in two phases: The initial intensive phase consists of drugs used in combination to achieve raid destruction of cells and improvement of patient condition (2 month period) The continuation phase time frame varies depending on risk of relapse Antitubercular Drugs MOA: Vary depending on drug – act to inhibit protein synthesis, cell wall synthesis, or other mechanisms. Table 46.1 pg. 756 Indications: TB infections both pulmonary& extrapulmonary Contraindications: Severe drug allergy, kidney/liver dysfunction, alcohol use Interactions: Major interactions. Table 46.4 pg. 757 Antacids, Dilantin, Anticoagulants, Benzos, Beta blockers, hypoglycemics, contraceptives = all alter therapeutic effects of antitubercular drugs Fairly well tolerated Liver toxicity – give Vitamin B6 to help with same Adverse Effects: Antitubercular Drugs Dizziness Headache GI upset Visual disturbances Insomnia Table 46.3 pg. 757 Antitubercular Drugs: Nursing Implications Obtain a thorough medical history and assessment. Perform liver function studies in patients who are to receive INH or rifampin (especially older adult patients and those who use alcohol daily). Assess for contraindications to the various drugs, conditions for cautious use, and potential drug interactions Patient education is critical. Therapy may last for up to 24 months. Have patient take medications exactly as ordered at the same time every day. Emphasize the importance of strict adherence to the regimen for improvement of condition or for cure. Remind patients that they are contagious during the initial period of illness—instruct them in proper hygiene and prevention of the spread of infected droplets. Antitubercular Drugs: Nursing Implications Teach patients to take care of themselves, including getting adequate nutrition and rest. Patients who are taking rifampin should be told that their urine, stool, saliva, sputum, sweat, or tears may become reddish orange; even contact lenses may be stained. Oral preparations may be given with food to reduce gastrointestinal upset. Observe for and monitor adverse effects Monitor patient for therapeutic effects. Decrease in symptoms of TB, such as cough and fever Laboratory study results (culture and sensitivity tests) and chest X-rays should confirm clinical findings. Watch for a lack of clinical response to therapy, indicating possible drug resistance. ANTIFUNGALS This Photo by Unknown Author is licensed under CC BY Fungal Infections Fungi are a large and diverse group of microorganisms that include all yeasts and moulds Yeasts: Single celled fungi that reproduce by budding Moulds: Multicellular, characterized by long, branching filaments An infection caused by fungus is called a mycotic infection Can be superficial, cutaneous (skin), subcutaneous, or systemic Fungal infections can be acquired by various routes: Ingested orally; Grow in skin, hair, or nails; Inhalation of fungal spores if airborne Fungal Infections Mycotic Infections Candida albicans May follow antibiotic therapy, antineoplastics, or immunosuppressants (corticosteroids) May result in overgrowth and systemic infections Growth in the mouth is called thrush or oral candidiasis. Common in newborn infants and immunocompromised patients Vaginal candidiasis Yeast infection Pregnant women, women with diabetes, women taking oral contraceptives Antifungals Variety, but a small group of drugs because fungus itself has proven to be very difficult to kill MOA: Differ between the drug subclasses, they all ultimately prevent the fungal cells from growing and reproducing OR affect the cell wall of the fungus which causes the cell to swell and burst Examples: Diflucan (fluconazole), Mycostatin (nystatin), Flagyl (metronidazole) Indications: Given Oral, topical, vaginal, as well as intravenous for systemic and topical fungal infections Contraindications: Drug allergy, liver failure, kidney failure are the most common Antifungals Interactions: Table 47.3 pg. 767 Corticosteroid therapy coupled with antifungal use can result in severe superinfection Oral anticoagulant activity is decreased when given with some antifungals Alcohol use with antifungals will increase alcohol potency H2 blockers can interfere with the absorption of some antifungals Flagyl and alcohol have a severe reaction if given together Nursing Implications: Educate on the importance of avoiding alcohol Monitor S/S especially if given with steroids Encourage patient to finish entire duration of therapy Shake oral suspensions before use; keep suspension in the mouth for as long as possible before swallowing ‘swish & swallow’ Keep skin, hair and nails clean Monitor I/V infusion q15 min at the onset to assess for adverse reactions Adverse Effects: Antifungals GI upset most common Can cause renal impairment Hepatic disease Hematologic problems Many reactions to systemic antifungals mimic the disease itself Overdose can include severe nausea, vomiting and diarrhea Table 47-2 for selected antifungals w/ common adverse effects p. 767 “Shake and bake” syndrome r/t IV amphotericin admin p. 767 Antifungals: Nursing Implications Before beginning therapy, assess for hypersensitivity, possible contraindications, and conditions that require cautious use. Obtain baseline vital signs, complete blood count, liver and renal function studies, and electrocardiogram. Assess for other medications used (prescribed and over the counter), to avoid drug interactions. Follow the manufacturer’s directions carefully for reconstitution and administration. Monitor vital signs of patients receiving intravenous (IV) infusions every 15 to 30 minutes. During IV infusions, monitor input and output to identify adverse effects. Antifungals: Nursing Implications amphotericin B To reduce the severity of the infusion-related reactions, pretreatment with an antipyretic (acetaminophen), antihistamines, antiemetics, and corticosteroids may be given. Use IV infusion pumps and the most distal veins possible. Some oral forms should be given with meals to decrease gastrointestinal upset; others require an empty stomach. Be sure to check. Monitor therapeutic effects. Easing of symptoms of infection Improved energy levels Normal vital signs, including temperature Watch for and carefully monitor adverse effects. Across the Lifespan Antimicrobials Need to educate on importance of hand hygiene; especially in young children Question overuse of antimicrobial agents Educate the importance of finishing a course of antimicrobials Monitor senior citizen exposure; educate re: same C & S important in determining necessity of antibiotic Review and compare dosage calculations when administering; especially with young children Monitor children closely especially if given antimicrobial for the first time Comorbidities (especially in older adults) may interfere with compliance