Chapter 12 Flashcards
what are the 3 principles of antimicrobial therapy?
*administering a drug to an infected person that destroys the infective agent without harming the host’s cells
*target infectious microbes by destroying/interfering microbial structures and enzymes
*produced naturally or synthetically
antibiotics are common metabolic products of ___ and _____
aerobic bacteria and fungi
what did Paul Ehrlich do?
coined the term chemotherapy to describe chemicals that would act as “magic bullets” and selectively kill pathogens
who introduced the first “sulfa” drug?
Gerhard Domagk
who was the first to discover a naturally produced antimicrobial, pcn, in 1928?
Alexander Fleming
what is a chemotherapeutic agent?
any chemical used in the treatment, relief, or prophylaxis of a disease
what is an antibiotic?
a metabolic product of one microorganism that inhibits or destroys other microorganisms.
A drug that will kill a wide range of bacteria can be classified as a
broad spectrum
A drug that will kill a few types of bacteria (limited) can be classified as a
narrow spectrum
a drug that is made totally in the lab is considered___
synthetic
a drug that is chemically modified in the lab after being isolated from the natural source is considered as
semisynthetic
the amount of medication given during a certain time interval is the ____
dosage
_____ is determined carefully to ensure the optimum therapeutic drug levels are achieved at the site of infection without causing significant toxicity (side effects) to the patient. allergic reactions and other potential S/E may still occur.
dosage
what is the route of administration?
is the method used to introduce the drug into the body. Drugs that can be administered orally are generally preferred because the patients can more conveniently take the drugs at home
when drugs cannot be absorbed in the GI tract, the drug is administered by a _____ route. (IV or IM injection)
parenteral
antimicrobial drugs work in through what 5 different ways?
- cell wall
- cell membrane
- protein synthesis
- nucleic acid
- cytoplasm
describe how antimicrobial drugs work in the cell wall
peptidoglycan in the cell wall helps provide a rigid structure that protects against changes in the osmotic pressure in the environment. Active cells are constantly producing more peptidoglycan to place in the cell wall. Some drugs interfere with one or more of the enzymes required to compete this process, causing the cell to develop weak points at growth sites and to become osmotically fragile.
Examples: pcn and cephalosporins
describe how antimicrobial drugs work in the cell membrane
damage to cell membrane causes disruption in metabolism or lysis. These drugs target a special type of lipids.
Examples: polymyxins, amphotericin B, nystatin
describe how antimicrobial drugs work through protein synthesis
block transcription or translation
Examples: streptomycin, gentamicin, tetracyclines, chloramphenicol, erythromycin
describe how antimicrobial drugs work in nucleic acid
block synthesis of nucelotides or replication. Examples: chloroquine and antiviral drugs like AZT
describe how antimicrobial drugs work in the cytoplasm
prevent metabolic pathway
Examples: sulfonamides and trimethoprim
fungal cells are eukaryotic; a drug that is toxic to fungal cells is also toxic to human cells
true or false
true
antifungal drugs are divided to treat 2 types of disease ____ and _____
superficial and systemic
what is the most common mode of action for antifungal drugs?
disrupting the cell membrane of the fungus
name 4 different types of antifungal drugs
Polyenes, Allylamines, Fluconazole, Imidazoles
describe Imidazole (antifungal drug)
otc with topical application
include: miconazole, ketoconazole, clotrimazole
found in otc products: Micatin, Lotrimin, Nizoral
used for ringworm and vaginal yeast infections
describe Fluconazole (antifungal drug)
orally or IV
systemic yeast infections: oral thrush and cryptococcal meningitis
describe Allylamines (antifungal drug)
most common, mostly used topically for ringworm
brand name: Lamisil
describe Polyenes (antifungal drug)
*Amphotericin B- used for systemic fungal infections = “Gold standard”
*Nystatin- used topical or orally for treatment of yeast infections of skin, mouth or vagina
what are the 4 major modes of action for antiviral drugs
*inhibition of viral release
*inhibition of nucleic acid synthesis
*inhibition of reverse transcriptase
*inhibition of viral assembly or release
antiviral drugs that inhibit viral release are
Amantadine (rimantadine), Tamiflu, and Relenza
*used in the treatmetn of influenza infections, decreased flu symptoms and shorten duration
antiviral drugs that inhibit nucleic acid synthesis
Acyclovir (zovirax)= Guanine analog (used to treat herpes inf. chickenpox & shingles)
Ribavirin= Guanine analog (used to treat hepatitis and RSV)
antiviral drugs that inhibit reverse transcriptase
AZT (azidothymidine)
thymine analog, used to treat AIDS
what are some major s/e people have after taking antimicrobial drugs
5% of people will experience s/e
damage to tissues or toxicity: liver/kidney
disruption in balance of normal flora= development of a superinfection
ex: diarrhea, vaginal yeast inf.
what are some considerations in selecting an Antimicrobial drug
*identify the microorganism causing the infection
*test the microorganism’s susceptibility to various drugs in vitro when indicated
*overall medical condition of the patient
what tests are used to test for drug susceptibility
Kirby-Bauer technique, tube dilution technique, E-test diffusion test
