antibiotics, antivirals, antihelminthics, antifungals, antiparasitics Flashcards
categories, idications, drug interactions, adverse reactions activity
Categories of antibiotics
PCNs, cephalosporins, macrolids, fluoroquinolones, lincoside, azalides, ketolides, oxalodinones, sulfonamides, trimethaprim, nitrofurantoin, tetracycline, vancomycin, antimycobacterials
What are the main causes of antimicrobial resistance?
Overuse of broad spectrums, use in children under 2 and older than 65, day care centers, exposure to young children, multiple medical comorbidities, immunosuppression
What is an antibiogram?
Chart that shows antibiotic resistance in your area
What vaccination has decreased antibiotic resistance?
Pneumococcal vaccine
What are PCNs and cephalosporins known as?
Beta-lactmas
How do beta lactams kill bacteria?
Inhibits peptidogylcan in cell walls; leads to cell lysis
What bacteria are the natural PCNs good against?
Streptococcus, some Enterococcus, some non-penicillinase producing staphylococcus
Which PCN is more able to attack gram negative?
Ampicilllin, because it can more easily penetrate outer membrance
What strains is ampicillin effective against?
gram negative UTI and GI, like E coli, P. mirabilis, salmonella, some shigella and some enterrococcus
What respiratory pathogens is ampicillin effective against?
moraxella catarrhalis and H influenzae type by
What are often combined with beta lactams to broaden their spectrum of activity?
clavulanate, tazobactam, slbactam
How are PCNs absorbed?
Well absorbed in GI, some affected by acid
Which PCNs are absorbed the best?
Doxacillian and amoxicillin better than ampicillin
What is the distribution, metabolism and excretion of PCNs?
Most bound to plasma proteins, well distributed, small amount metabolized, largely in urine
What drug prolongs the half-life of PCNs and increases its risk for toxicity?
Probenecid
What are the most common adverse reactions of PCNs?
- allergic reactions within 2 to 30 minutes; can be relieved by desensitization therapy
- rash that is not allergic within 7 to 10 days
- GI stuff made worse by clavulanate
- Fungal overgrowth and C diff
What pregnancy category are PCNs?
Category b
What are PCNs primarily used for, and dosing?
- infections seen in primary care
- first line for AOM and sinusitis
- Streptococcal pharyngitis (strep A)
- UTI in pregnant women
What is the first line of treatment for bites?
Amoxicillin-clavulanate
What are key considerations in rational drug selection?
rapid strep test vs. empirical, and cost
What should be monitored in PCNs?
symptom relief , possible resistance, possible viral
What should patient education of PCNs be?
course completion, resistance, adverse reactions
How do cephalosporins work?
inhibit mucopeptide synthesis in cell wall, leads to lysis
How many generations of cephalosporins are there?
4 primary
What are the first generation cephalosporins active against?
skin and soft tissue infections caused by gram positive bacteria like s. aureus and s. epidermis
What are second generation cephalosporins active against?
same as first generation plu kiebsiella, proteus, and E coli
What are third generation cephalospoins goos against?
broader spectrum and better against gram negative
What are fourth generation cephalosporins good for?
They are resistant to beta lactamase and are active against both gram positive and gram negative bacteria.
What is a hospital associated pathogen that fourth generation cephalosporins are active against?
Pseudenomas
How are cephalosporins absorbed, metabolized, and excreted?
absorbed in GI, widely distributed to tissues, mostly bound to proteins; some metabolites formed, most excreted through kidneys, varying degrees of unchanged drug in urine
What are adverse drug reactions assoicated with cephalosporins?
allergies, skin rashes, arthalgia, coagulation abnormalities, anemai, neutropenia, leukopenia, thrombocytosis, fever, seizures, renal/hepatic failure
What are cephalosporins used for, and dosing?
Used in acute otitis media when PCNs have failled;
The first generations are used for strep pharyngitis and skin infections;
They can be used as second line drugs for UTIs
Several can be used for comunity acquired pneumonia
What should be monitored with cephalosporins
C diff and renal function
What is patient education for cephalosproins?
Use as prescribed
How do fluoroquinolones work?
Interfere with enzyme needed for DNA synthesis
What bacteria are fluoroquinolones really good against?
gram negative
Which population should not receive fluoroquinolones?
Children under age of 18
What can fluoroquinolones no longer be used for because of resistance?
Gonorrhea and resistance TB
How should fluoroquinolones be taken?
On empty stomach for good absorption
What is the black box warning for fluoroquinolones?
tendon rupture
What are other adverse reactions of fluoroquinolones?
C diff, CNS symptoms, renal/hepatic failure, cardiovascular issues and arrythmias, pregnancy issues
What are the clinical uses for fluoroquinolones?
complicated UTIs, kidney infections, complicated bacterial prostatitis
pneumonia and chornic bonchitis exacerbation
PCN-resistant S. pneumonia, skin infections, bone/joint infections, serious intraabdominal diarrhea
What should be monitored for when using fluoroquinolones?
watch for prolonged use, in high risk patients get EKG before using moxifloxacin, alcohol use, tendonitis rupture
What should patient education for fluoroquinolones be?
food delays absorption, lots of drug interactions, take with a glass of water, watch out for dizziness, if tendon tenderness stop and notify doctor
What is the only used drug of the lincosides?
Clindamycin (Cleocin)
What is Clindamycin used for?
only gram positive: corynbacterium acnes, garnarella vaginallis, some MRSA
What does Clindamycin not work against?
gram negative
How is clindamycin absorbed?
Oral completely absorbed, not affected by gastric acid
What are adverse drug reactions associated with clindamycin?
severe colitis, dermatological stuff, thrombocytopenia, neutropenia, eosinophilia
What is clindamycin used for, and dosing?
First line for MRSA in some areas, used in PCN resistnat patients, resistant strep pneumonia, dental infections
What is the rational drug selection for clindamycin?
It’s considered 2nd line, and only has narrow spectrum aerobic activity; it can be first line in children and pregnancy
What should be monitored for with clindamycin?
diarrhea, especially C diff potential
What should patients be educated about with clindamycin?
diarrhea and C diff, finish therapy
What is a well known drug from the macrolides, azalides, and ketolides?
Erythromycin
How do macrolides work?
inhibits ribosome protein synthesis
What makes macrolides increase in activity
alkaline environments/media
What kinds of bacteria are susceptible to macrolides?
atypicals and intracellular organisms that are resistant to beta lactams
What is the resistance in macrolides like?
Cross resistance to all in the class
Describe absorption and metabolism for macrolides?
Well absorbed in duodenum; inhibitors of CYP 450 enzyme
What happens when macrolides are combined with statins?
Increases risk of myopathy
What unusual thing does macrolides do after absorption?
Enterohepatic recycling, which leads to build up in system; causes N/V; levels higher in tissues than in serum
What are precautions for macrolides?
Statins; safe in pregnancy and children
What are adverse drug reactions in macrolides?
dose related GI issues, N/V/D, abdominal cramping
skin issues, Steven-Johnson
What are drug interactions of macrolides?
statins, CYP 450 enzyme
What are clinical dosing and use of macrolides?
primary use for mycoplasm community acquired pneumonia (zithromax); chlamydia, pertussis, H. pylori (clarithromycin), chronic bronchitis
What is the rational drug selection for macrolides?
alternative to PCn allergy, inreasing resistance, don’t use for AOM or sinusitis
What should be montiored for with macrolides?
altered metabolism responses to other drugs by CYP450 and 2C9; hepatic/renal problems, hearing loss
What should patients be educated about with macrolides?
ADR and drug interactions
How do sulfonamides work?
inhibit folic acid synthesis
How does trimethaprim work?
inhibits DNA synthesis
How does nitrofurantoin work?
inhibits acetyl coenzymes
What kind of bacteria are sulfonamides, trimethaprim, and nitrofurantoin effective against?
Gram positive and gram negative
What specific bacteria can s, t, and n be used with?
E coli, s. pyogenes, s. pneumonia, h. influenze, and some protozoa
What are adverse drug reactions of s, t, and n?
GI issues, stomatitis, rashes, hypersensitivity, photosensitivity, CNS, dizziness, drug interactions
When should s, t, and/or n be avoided?
G6PD defiency
What is the clinical use and dosing of s, t, and n?
Mostly UTI, sometimes MRSA
What is the rational drug selection for s, t, and n?
lost cost alternative in children when they have PCN allergies
What should be monitored with s, t, and n?
control in UTI, CBC if using long term, chest xray if cough with nitrofurantoin
What is the patient education for s, t, and n?
Finish course, ADRs, reactions
What is the primary drug in oxazolidinones?
Linezolid
How does linezolid work?
inhibits ribosomal protein synthesis
What is linezolid most helpful against?
aerobic gram positive
What is the absorption for linezolid?
well absorbed orally, doesn’t interfere with CYP450 enzymes
What are ADRs with linezolid?
D/HA/N, myelosuppression that resolves after quitting drug
When should linezolid be used?
pneumonia and complicated skin infections, but try less expensive drugs first
What is the rational drug selection for linezolid?
high cost, use if resistance to vanc is a problem
What is the patient education for linezolid?
ADRs and patient administration
What are the two main drugs in the tetracyclines?
Tetracycline and doxycycline
How do tetracyclines work?
they bind to the 30S unit of the ribosome
How is absorption of tetracylcines affected?
Food, milk and calcium decrease absorption
What are precautions and contraindications with tetracyclines?
don’t give to pregnant or lactating women, children less than 8 because of dental issues
What are the drug interactions with tetrayclines?
many
What is the clinical use and dosing for tetracylcines
doxycycline is first line for trachomatis and U.urealyticum, p. acnes, and some h. pylori regimens
What is the rational drug selection for doxycycline?
doxycycline and minocycline can be taken with food; tetracycline not so great anymore b/c of resistance
What is patient education for tetracyclines
administration, AdRs, avoid during pregnancy
What is an example of a lipoglycopeptide?
Vancomycin, telavancin, and dalbavancin
What are lipoglycopeptides used for?
severe gram positive infections that are resistant to first line
How do lipoglycopeptides work?
Inhibit cell wall synthesis
How are lipoglycopeptides abosrbed?
Not well orally, given IV
What are ADRs for lipoglycopeptides?
ototoxicity, nephrotoxicity, Red Man syndrome if given too fast
What is the clinical use and dosing for lipoglycopeptides?
serious gram positive when MRSA coverage is necessary or there are PCN issues
What should be monitored for with lipoglycopeptides?
Hearing and renal function
What should patient education for lipoglycopeptides be?
Administration and ADRs
What are mycobacteria?
Slow growing bacteria that are resistant to drugs that depend on how rapidly cells divide
What makes mycobacteria resistant to drugs?
Lipid rich cell wall
What is unique about mycobacteria?
They can go dormant and easily become resistant to single drugs
What are the main mycobacterials?
isoniazid, ethambutol, and rifampin
How do isonizaid, ethambutol, and rifampin work?
INH and ethambutol inhibit synthesis of mycolic acides, ehtambutol inhibits arabinogalactan needed for cell walls, rifampin binds to subunit of RNA polymerase and inhibits RNA synthesis
What are the resistant issues with mycobacteria drugs?
Quickly develop resistance, cross resistance with INH and ethionamide
How are mycobacteria drugs absorbed?
Well absorbed orally, metabolism of INH varies widely, dependent on acetylator status
What are the ADRs of antimycobacterials?
INH: peripheral neuropathy,
INH, rimfapin, and pyrazinamide: hepatotoxicity
ethambutol: optic neuritis
streptomycin and capreomycin are ototoxic
Rifabutin: thrombocytopenia and neutropenia
What are the drug interactions of antimycobacterials?
many drug interactions; rifampin is CYP450 inducer
What is the clinical use and dosing for antimycobacterials?
Follow CDC guidelines, TB requires 4 drug therapy, Preventive therapy with INH
What is rational drug selection for antimycobacterials?
Follow CDC guidelines
How should antimycobacterials be montiored?
Directly observed
What is the patient education for antimycobacterials?
Take medications daily, report ADRs
What are nucleoside analogues for?
antirvirals
How do nucleoside analogues work?
block entry to cells or be active inside cells to be effective
What is acyclovir active against?
herplex simplex 1 and 2, varicella-zoster, epstein-barr, cytomegalovirus and herpes virus 6
What is valacyclovir good against?
converts to acyclovir and then active against same things
What is famciclovir good against?
HS1-2, VZ, EB, and Hep B
What is ganciclovir good for?
CMV
What are ADRs of the nucleoside analogues?
acyclovir: few when given orally
valacyclovir can causes thrombocytopenia pupura and hemolytic uremia in immunosuppressed
famciclovir causes headeache
Ganciclovir can cause blood cell issues, carcinogenic
What are the drug interactions of nucleoside analogues?
Few
What are the clinical uses and dosing for nucleoside analogues?
herpes simplex genital herpes intial outbreak and suppression;
Herpes zoster (shingles) start within 3 days;
Varicella (chickenpox) start within 24 hours;
gingivostomatitis in children
Bell’s palsy
What are the rational drug choices regarding nucleoside analogs?
Choice based on cost and convience
What is the monitoring for nucleoside analogs?
monitoring rash, temperature, BUN and creatinine in high risk patients
What is the patient education for nucleoside analogs?
Start drug at earliest sign of infection, stay hydrated, and teach signs of renal failrue, encephalopathy, and blood dyscrasias
What are the main antivirals for influenza?
oseltamivir (tamiful), peramivir (rapivab), and zanamivir (Relenza)
Which flus do the influenza antivirals treat?
A and B
What are the pharmacodynamics of the flu antivirals?
Sensitivity varies each year; rimartidine and amratidine have resistance - no longer recommended for the flu
Describe absorption for flu antivirals?
oseltamiviir is well absorbed orally; Zanamivir is inhaled with less than 17% absorption; peramivir is givene IV
What are the adverse drug reactions for flu antivirals?
Zanamivir: bronchitis and SOB
What is the clinical use and dosing for flu antivirals?
oseltamivir and zanamivir good for prophylaxis and treatment of A and B; peramivir is only for acute flu in those 18 or older; CDC guidelines need to be evaluted annually
What should be montiored for with the flu antivirals?
renal function in older people, hallucinations, confusion and cognitive impairment in elderly
What is the patient education for flu antivirals?
complete full course of therapy, ADRs, get flu vaccination every year
What type of drug are system azoles?
Anti-fungals
What are the polyene macrolides?
Anti-fungals amphotericin B and nystatin
What azoles have broad spectrum activity?
butoconazole, clotrimazole, ketoconazole, minonazole, terconazole, etc.
What kind of anti-fungals are good against yeast and dermatophytes?
alklyamines
What are examples of the alklyamine anti-fungals?
naftifine, terbinafine
What are nuclear acid synthesis inhibitors for?
anti-fungal
What is an example of a nuclear acid synthesis inhibitor?
flucytosine
What is griseofulvin?
An anti-fungal
What are the pharmokinetics of antifungals?
absorption of itraconazole is enhanced by food;
absorption of griseofulvin is enhanced by fat;
fluconazole inhibits CYP450 and 2C9
itraconazole and ketoconazole inhibit CYP450
What are the adverse drug reactions of the antifunglas?
hepatotoxicity
What are the drug interactions of anti fungals?
Many mess with CYP 450
What is the clinical use and dosing for antifungals?
oral fungals treat yeast and dermatophytes, and invasive systemic mycoses; fluconazole requries a loading dose
What is the rational drug selection for anti-fungals?
Fluconazole has the fewest drug interactions
What should be monitored with the anti fungals?
ketoconazole needs liver enzyames and bilirubin every 3-4 months
What is patient education for antifungals?
take with food, don’t use alcohol, watch for signs fo liver damage
How do antihelminthics work?
intestintal nematodes treated with mebendazole, pryantel, and thiabendazole;
tissue nematodes treated with mebendazole, thiabendazole, ivermectin, and albendazole
How many cases of pinworm are treated yearly in the US?
50 million
What are the adverse drug reactions for antihelminthics?
N/V/D, abdominal pain, mebendazole can cause neutropenia, Ivermectin can cause Mazzotti reaction.
What is the clinical use and dosing for antihelminthics?
pinworms: single dose of mebendazole or pyrantel, or albendazole;
whipworms: mebendazole, albendazole, or pyrantel;
round worms: mebendazole;
hookworms: mebendazole, albendazole, pyrantel
threadworm: ivermectin or thiabendazole
scabies: off label ivermectin in immunocomprimised people
What is the rational drug selection for antihelminthics?
See CDC guidelines
What should be monitored for with antihelminthics?
albendazole and mebendazole need to be given with high fat meal;
Ivermectin should be taken without food;
Albendazole should not be taken during pregnancy and there should be back up contraceptive
What is metronidazole?
Treats both bacterial and parasitic infections;
Good against trichonomas, amoebas, h. pylori, and C fdiff
What is nitazoxanide for?
Treats giardia and cryptosporidium
What is tinidazole for?
amoebas, giardia, and trichonomas
What are the pharmakinetics of metrinodazole?
Well absorbed orally
What are the ADRs with the antiparasitic drugs?
mitronidazole can cause anorexia, N/V, metallic taste, abdominal pain
What is the clinical use and dosing for the antiparasitics?
metronidazole and tinidazole are for protozoan infections;
metronidazole can help with anaerobic bacterial infections, vaginosis, and is used in H. pylori treatment
What is the rational drug selection for the antiparasitics?
metronidazole is cheap, don’t use during first trimester of pregnancy
What should be monitored with the anti parasitics?
resolution and signs of neutropenia
What is the patient education for antiparasitics?
administration, metallic taste, avoid alcohol, partner might also need treatment
