Pharm Exam 2: Infectious disease Flashcards

Question

``` Aminoglycosides Pharmacodynamics mono therapy no recommended Gentamicin Amikacin Tobramycin Neomycin Streptomycin ```

Answer 1

They are actively taken up by bacteria and subsequently bind to the smaller 30S subunit of the bacterial ribosome, thus inhibiting bacterial protein synthesis. Active against gram negative bacilli e.coli, clebsiella, enterobacter Must be used in combination with a cell wall agent for gram+ activity Staph, enterococcus, strep

Answer 2

IV administration only, poorly absorbed GI Weakly serum protein bound and excreted by kidneys Adjust dose in renal patients – removed by hemodialysis Monitor renal function and serum levels * narrow therapeutic range

Answer 3

Drug-resistant gram-negative infections Synergy against gram positive cocci in combination with cell-wall agent (i.e. gentamicin) Empiric treatment in combination with other abx for hospital acquired infections - UTI, pneumonia

Answer 4

Mild and transient GI and CNS effects Rare hypersensitivity Nephrotoxicity and ototoxicity - Accumulation of drug in the proximal tubule cells - Otoxicity may be irreversible and Is associated with high serum trough levels. Extended interval dosing (i.e. 6mg/kg q24hr) associated with lower risk of renal and ototoxicity (may be irreversible)

Answer 5

Pharmacodynamics - Inhibits bacterial protein synthesis by binding to the 30S subunit of the ribosome. Pharmacokinetics - Food decreases absorption (take on empty stomach) - Highly protein bound - Renally excreted (except doxycycline) - Milk and dairy products impair absorption

Answer 6

Possess activity against gram +/- and atypical organisms Doxycycline is considered first-line therapy for Chlamydia trachomatis and the drug of choice for early Lyme disease, Community acquired PNA Tetracycline and minocycline used to treat P. acnes Minocycline/doxycycline-community-acquired MRSA infections Patient Education Administration, ADRs, avoid pregnancy

Answer 7

Do not prescribe to pregnant women, lactating women or children < age 8 yrs Drug-drug CYP3A4 interactions Anorexia, nausea, vomiting, epigastric pain Thrombophlebitis Hepatotoxicity Tooth discoloration Sun sensitivity (avoid the sun) * infuse slowly w/ large volume

Answer 8

Work by inhibiting the incorporation of paraaminobenzoic acid used by bacteria to synthesize dihydrofolic acid, the first step leading to folic acid synthesis, which is required for bacterial cell growth. Readily absorbed in the GI tract and well distributed Metabolized by the liver and eliminated by the kidneys Half lives vary from hours to days

Answer 9

Active against a wide range of gram +, gram - organisms. Most commonly used for UTI, pyelonephritis (BACTRIM) Low cost alternative PCN allergies

Answer 10

Anorexia, n/v, diarrhea, stomatitis Rash Stevens-Johnson syndrome/toxic epidermal necrolysis - Rare

Answer 11

Monitoring: Culture and susceptibility if treating for UTI long term use check CBC Resistance potential * Cx and sensitivity prior to starting abx Patient Education: Complete antibiotic course ADR’s

Answer 12

Pharmacodynamics - Work by inhibiting the binding of the D-alanyl-D-alanine portion of the cell precursor or by interfering with the polymerization and cross-linking of peptidoglycan. - Gram + aerobic/anerobic bacteria - Weight-based dosing Pharmacokinetics - IV only for systemic therapy - PO is reserved for C-Diff treatment - Poorly absorbed from the GI tract - Must monitor renal function

Answer 13

Empiric therapy for severe infections with risk for gram-positive organisms - Endocarditis - Meningitis - Neutropenic fever with gram-positive risk - MRSA * for pt unable to tolerate beta lactams Clostridium difficile - PO only * for those unresponsive to metronidazole

Answer 14

Fever, chills, phlebitis Nephrotoxicity/Ototoxicity (transient or permanent) ``` “Red Man” syndrome Infusion related Prolong infusion time to avoid (i.e. 2 hours) redness, itching, hypotension * stop med * premed w/ Benadryl ```

Answer 15

Pharmacodynamics - Disrupts bacterial protein synthesis - Most effective against gram-positive aerobic bacteria - Enterococci, staphylococci, and streptococci - Resistance emerging Pharmacokinetics - Well absorbed orally from the GI tract - Does not use CYP 450 enzymes - Considered bacteriostatic agents

Answer 16

Linezolid has been FDA approved for the treatment of: Community acquired and nosocomial pneumonia Skin and soft tissue infections Osteomyelitis Vancomycin-resistant enterococcus MRSA PCN resistant streptococci, VRE Tedizolid: Only for treatment of skin and skin structure infections

Answer 17

Diarrhea, headache, nausea, vomiting, and taste perversion. Myelosuppression has been reported, resolves with discontinuation Decreased blood counts - Thrombocytopenia, anemia, leukopenia, pancytopenia * can decrease blood counts over long term

Answer 18

Pharmacodynamics - Binds to the 50S subunit of the bacterial ribosome and inhibits protein synthesis. - Well absorbed and converts to active form in the blood. Pharmacokinetics - Metabolized by the liver - Reaches most tissues/bone, limited distribution into CSF - Half-life is approximately 3 hours

Answer 19

Used to treat gram +/- and anaerobic bacterial infections Toxoplasmosis, PCP, or in combo with other agents to treat PID. Pregnancy category B

Answer 20

Boxed warning for severe colitis-or CDAD * diarrhea Skin –pain at the IV site - Rash , burning, itching, erythema Hematologic - Transient eosinophelia, neutropenia, thrombocytopenia

Answer 21

Monitoring - Stop medication if significant diarrhea occurs Patient Education: - Advise patients to take probiotic with therapy - Complete therapy - ADR’s

Answer 22

Pharmacodynamics - It is reduced to a toxic product that interacts with DNA, causing stand breakage results in protein synthesis inhibition. - Metronidazole treats both protozoal and bacterial infections , gram +/- anaerobes - Active against trichomoniasis, Clostridium difficile, H. Pylori regimen, and bacterial vaginosis. Pharmacokinetics - Metronidazole is well absorbed when taken orally

Answer 23

Clinical Use and Dosing Empiric therapy, often in combination with other antibiotics, for infections with risk for anaerobic organisms Intra-abdominal, aspiration pneumonia, bacterial vaginosis Adverse Drug Reactions GI complaints: N/V, abdominal pain, and a metallic taste. High doses: risk of seizures Prolonged courses: risk of peripheral neuropath* pancreatitis avoid ETOH can enhance anticoagulation of warfarin Patient Education Inhibitor of CYP3A4 Metallic taste with metronidazole Avoid alcohol due to disulfiram-like reactions

Answer 24

Is a type of germ that grows slowly and are relatively resistant to drugs that are largely dependent on how rapidly cells are dividing Have a lipid-rich cell wall relatively impermeable to many drugs Are usually resistant to drugs that do not have good intracellular penetration Have the ability to go into a dormant state Easily develop resistance to any single drug

Answer 25

Pharmacodynamics - Rifampin suppresses initiation of chain formation for RNA synthesis in susceptible bacteria by inhibiting DNA- dependent RNA polymerase. - Resistance develops rapidly to monotherapy - Extremely active against gram + cocci with moderate activity against aerobic gram - bacilli Pharmacokinetics - Well absorbed orally - Metabolism of isoniazid is highly variable

Answer 26

Clinical Use and Dosing Follow CDC guidelines Active TB requires 4 drug therapy Preventive therapy with INH Rational Drug Selection Follow CDC guidelines Monitoring Directly Observed Therapy (DOT) Patient Education Importance of taking medication daily Reporting of ADRs

Answer 27

Adverse Drug Reactions INH: peripheral neuropathy INH, rifampin & pyrazinamide: hepatotoxicity Rifampin: red-orange color to body fluids Monitor LFTS: rare risk of hepatotoxicity Anemia/thrombocytopenia has been reported Drug Interactions Many drug interactions Rifampin is an inducer of CYP450 enzyme

Answer 28

Pharmacodynamics Viruses are obligate intracellular parasites that consist of a nucleic acid core surrounded by one or more proteins. Several mechanisms exist for replication. Antivirals work by inhibiting DNA replication. Acyclovir, valacyclovir, famciclovir: active against HSV 1 and 2; varicella-zoster virus (VZV); Epstein-Barr virus (EBV), herpes B virus

Answer 29

Clinical Use and Dosing Herpes simplex virus: genital herpes both initial outbreak and suppression therapy Herpes zoster (shingles) Varicella (chickenpox) * Not for pt < 12yo * caution in renal disease * C/I in CHF and lactation

Answer 30

Adverse Drug Reactions Headache, nausea, rash, nasopharyngitis, ALT/AST increase Drug interactions Few Monitoring Monitor for improvement and resolution Patient Education Drug started at earliest sign of infection Hydration

Answer 31

Pharmacodyanimcs - Zanamivir and oseltamivir inhibit influenza virus neuraminidase, - Amantadine and rimantadine inhibit replication of influenza A - Amantadine, rimantadine (Flumadine) and - - - Oseltamivir (Tamiflu) are used to treat influenza A - Amantadine (Symmetrel) has been discontinued in the US - Zanamivir (Relenza) treat influenza A or B (inhaled) - Sensitivity varies by year Pharmacokinetics - Most are well absorbed after oral administration - Zanamivir is inhaled, 4 – 17% absorbed

Answer 32

Adverse Drug Reactions amantadine and rimantadine: CNS disturbances, abnormal dreams amantadine : peripheral edema Zanamivir: nausea, dizziness, headache, bronchitis, cough, nasal symptoms, ear/nose/throat infection, fever, malaise/myalgias, appetite changes Clinical Use and Dosing CDC updates recommendations annually. Amantadine has several drug interactions

Answer 33

Monitoring Resolution of flu symptoms CNS disturbances Patient Education Take full course of therapy ADRs Advise annual influenza vaccination * Encourage flu vaccine and dispel myths

Answer 34

Most common bacterial cause is Streptococcus pneumoniae Chest radiograph should be obtained A sputum gram stain should be obtained Travel history, local epidemiology, and other epidemiologic and clinical clues should be considered when selecting an empiric regimen. Drug-resistant Streptococcus pneumoniae complicates the use of empiric treatment.

Answer 35

Provide adequate hydration (replace losses). Bronchodilators for dyspnea. Fever control. Supplemental oxygen for hypoxia. Early identification of causative microorganism.

Answer 36

No requirement for hospitalization, have no major co-morbidities, and have not used antibiotics within the last 3 months, and reside in a region in which there is not a high prevalence of macrolide-resistant S. pneumoniae (<25 percent) Treatment: advanced macrolide-Azithromycin (500 mg on day 1 followed by four days of 250 mg a day or 500 mg daily for 3 days), clarithromycin (500 my twice daily), or clarithromycin XL (two 500 mg tablets once daily). For non pregnant patients with CAP who do not require hospitalization, have no major co-morbidities, and have not used antibiotics within the last 3 months but cannot take a macrolide due to a high local rates (> 25%) of macrolide-resistant S. pneumoniae or a contraindication and who live in a region in which the local rate of doxyclcyine-resistant S. pneumonia is 25% or is unknown- Treatment: doxycycline 100 mg PO twice daily. Most outpatients with CAP should be treated for 5 days, including those receiving azithromycin 500 mg on the first day followed by 250 mg daily on subsequent days and those receiving any other antibiotic. Because of its long half-life, patients receiving azithromycin at a dose of 500 mg daily can usually be treated for 3 days. Patients should be afebrile for >48 hours and clinically stable before therapy is discontinued. Patients who have not responded to therapy after 48 to 72 hours should be re-evaluated

Answer 37

A clinical prediction tool validated to predict mortality from CAP Assists with the decision to admit to hospital vs. outpatient management ``` Confusion BUN > 20 RR > 30 SBP < 90 DBP < 60 > 65 ``` CURB-65 is only used as a guide to decision making PNA s/s: cough, sputum production, chills, SOB, chest pain Physiologic exam: fever, tachycardia, crackles, tachypnea, decreased breath sounds

Answer 38

1st line: <60 yo, no comorbidities Macrolide Fluorquinolone 2nd line: comorbidities, > 60 yo Beta-lactam Beta-lactamase inhibitor 3rd line If no improvement Tx for 5-10 days

Answer 39

Induces defects in the immune response system. Patient is susceptible to various infections and neoplasms. Transmitted via blood, sexual contact and mother to child (vertical transmission). Prevention is the key to avoiding transmission. HIV is the virus that causes acquired immunodeficiency syndrome (AIDS). * primarily in lymph node and genital secretion

Answer 40

Stage I: Acute HIV infection 2-4 weeks after exposure Flu like illness with fever, rash, pharyngitis, adenopathies and myalgias Very contagious Stage 2: Clinical latency (HIV inactivity or dormancy) sometimes called asymptomatic HIV infection or chronic HIV infection. HIV is still active but reproduces at very low levels. Patients may or may not have any symptoms. Stage 3: Acquired immunodeficiency syndrome (AIDS)AIDS is the most severe phase of HIV infection. Advanced HIV/AIDS: CD4 below 200 cells/mm3 * very infectious; high viral load Develop common opportunistic infections s/s: chills, fever, swollen lymph glands, sweats, wt loss, weakness,

Answer 41

Diagnosis of HIV is based on the presence of: RNA or p24 antigen in serum/plasma Often with a negative/indeterminate HIV antibody test The CD4+ T-cell count indicates the extent to which HIV has damaged the immune system. Normal: 500-1600/mm3 * viral load tells how much HIV is reproducing * successful tx: rise in CD4 count and decrease in viral load to undetectable amount

Answer 42

Maximal suppression of viral load Also diminishes spread of virus. Restoration and preservation of immune system function. Enhancement of quality and duration of life. Reduction in morbidity and mortality from HIV-related complications. Prevention of HIV transmission

Answer 43

Work in the target cells to interfere with the transcription of RNA to DNA. Break into the chain of the RNA and replace a nucleoside analog or another non-nucleoside component so that the DNA is not produced. Many drug interactions due to CYP450.

Answer 44

Renally excreted. Need dose adjustment in renal failure. Lactic acidosis with hepatic steatosis. Decrease in bone mineral density. Hypersensitivity reaction. Headache, malaise, GI disturbances. Some dosing schedules are based on weight. Combination drugs: Truvada

Answer 45

By binding to reverse transcriptase, NNRTIs also interfere with the conversion of RNA to DNA. Adverse effect: GI disturbances. Rash. Elevated hepatic transaminases. All of the NNRTIs are metabolized by the cytochrome P-450 3A4 isoenzyme system in the liver. Caution w/ liver disease

Answer 46

Activity late in the reproduction phase of the HIV virus, inhibiting the ability of the polyprotein chains to break apart and create new chains of the virus. Ultimately this decreases the production of viral RNA. Food decreases absorption unless boosted with another PI, Ritonavir.

Answer 47

N/V/D Increase in hepatic transaminases. Monitor for hepatotoxicity Fat maldistribution: Fat lipodystrophy Hyperlipidemia Hyperglycemia -> DM Management: diet and exercise

Answer 48

Fuzeon (Enfuvirtide)-injected subcutaneously BID. Prevents fusion of the virus to the cell membrane of the CD4 host cell. Often useful in patients with other drug resistance. Local injection site reactions. <1% experience hypersensitivity reactions (rash/fever).

Answer 49

Prevents integration of viral DNA into the host cell’s genome. Includes dolutegravir, elvitegravir, and raltegravir Used in drug resistance/earlier treatment naïve patients.

Answer 50

Maraviroc Blocks the CCR5 receptor on the CD4 cell membrane. Not all viruses use this receptor for cell entry Co-receptor tropism must be performed to determine if pt virus enters via CCR5 BLACK BOX WARNING: Hepatotoxicity. Numerous drug interactions Requires dose adjustments s/s: cough, orthostatic hypotension, rash, fever

Answer 51

Adherence is the most crucial factor to success. ART is recommended for all patients with HIV. Recommended initial therapy is comprised of 2 NRTIs plus a third drug, either a boosted PI or INSTI. Evaluate HIV RNA and CD4+ count. LFTs, CBC with diff, CMP

Answer 52

Infant testing can start at birth and by age 4 months Initial test negative: repeat at age 1-2 months and age 4-6 months. CD4+ T cell counts in children <5 years higher than adult counts. Use CD4+ T cell count and viral load to accurately predict prognosis/survival. An HIV expert should manage pediatric patients.

Answer 53

ART thresholds same for men and women. ART selection in childbearing women-balance efficacy/potential of teratogenicity ART reduces efficacy of many PO contraceptives In pregnancy: 1. ART of HIV in the mother. 2. Prophylaxis to reduce risk of perinatal HIV infection. During Labor: ART chemoprophylaxis IV zidovudine * recommended for pregnant women w/ viral load > 1000 copies/mL during late pregnancy Postnatally: infant receives oral chemoprophylaxis

Answer 54

Post Exposure Prophylaxis (PEP) Occupational O-Pep-begin as soon as possible. Non-occupational N-Pep Begin within 72 hours of exposure for 28 days Preferred regimen: tenofovir/emtricitabine (TRUVADA) tablet PO daily PLUS raltegravir 400 mg PO BID

Answer 55

Pre exposure prophylaxis (PrEP) Truvada once daily 44% relative risk reduction in HIV infection incidence ADHERENCE IS IMPORTANT! Must receive safer sexual practices counseling. Must test negative for HIV within 1 week of PrEP initiation and every 3 months during treatment -> to prevent resistance 90 day supply, follow-up every 3 months.

Answer 56

Retrovirus Each molecule has 2 single strands of RNA Virus is transcribed, via reverse transcriptase, into DNA that inserts into DNA host cell -> replication Host cells: CD4, T-lymphocytes, WBC Host cell destruction -> immunocompromised stated * increase in CD4 may indicate noncompliance with medication

Pharm Exam 2: Infectious disease Flashcards

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