Antimicrobial Drugs Flashcards
Quinine alkaloids are found in this
Chinchona bark
which is a strong cardiodepressant, quinine or quinidine
Quinidine
one used to induce labour or abortion and why
quinine because contracts smooth uterine muscle
what is the mechanism of action of quinine salts
they bind to DNA inhibiting synthesis of plasmoidal nucleic acids
what is the selective toxicity of quinine salts
the uptake of quinine is in erythrocytes leading to an increased concentration at the site of action
In addition to antimalarial propertities, quinine salts also exhibit
antipyretic and analgesic properties
what are common side effects with quinine salts
- tinnitus
- myocardial hypotension
- blurred vision
- headache
- nausea
which stage of the lifecycle are quinine salts effective on
- para-erythrocytic
- schizonts and gametes
what is quinine normally used for
resistant malaria P. Falciparum
Name the antimalarial drugs (9)
- quinines & salts
- mepacrine
- Chloroquine
- primaquin
- mefloquin
- biguanides
- halofanring
- Pyrimethamine
- artemesinin
Chlorquine has a long or short half life which has led to ____dosing following an initial ____dose
- long
- weekly
- load
Chloroquines are more or less toxic than quinine and mepacrine
less toxic
what are some common side effects of chlorquine
- dizziness
- headache
- vomiting
- skin rash
these antimalarial drugs kill schizonts and gametes
- quinines
- mepacrine
- chloroquine
True/False: Primaquin acts against shizonts and gametes of malaria
false, it acts only against gametes
the mechanism of action of primaquin involves
binding to mitochondria of liver forms causing them to swell and be vacuated
primaquin is used for prophylaxis or cure
cure in combination with chlorquine
common side effects of primaquin include
- GI upset
- lukopenia
- hemolytic anemia in those with Glc-6-phosphate dhg
the mechanism of action of mefloquin
depends on interference of transport of hemoglobin from host cell to parasite food vacuole, binding to malrial pigment hemozoin
mefloquin has a long or short half life
long
adverse effects of mefloquin include
GI distrubance
CNS issues - confusion, insomia psychosis
Proquanil and Chlorproquanil are part of this class of antimalarials
Biguanides
this antimalarial is similar to the antibiotic trimethoprim
Pyrimethamine
pyrimethamine acts by inhibiting this enzyme which impairs DNA synthesis
dihydrofolate reductase
Artemesinin is derived from the chinese herb
quinghao
the mechanism of action of artemesinin
- acts on the electron transport chain
- generating local reactive oxygen
- cause depolarization of the mitochondrial memberane
Trichomoniasis is a protozoa commonly causing what
vaginalis
vaginalis is treated with
metronidazole
the source of toxoplasmosis is
the feces of dogs and cats, primarily cats
toxoplasmosis is especially dangerous for this patient population and why
- pregnant woment
- the parasite will cross the blood brain barrier causing fetal or neonatal death or congential deformities
these two drugs are used to treat toxoplasmosis
pyramethamine
sulfphdiazine
giardiasis lablia is treated with
metronidazole
what is selective toxicity
exploiting different structures and functions between host and parasitic organism
what are the four primary mechanisms of action of antimicrobials, give an example of a drug class for each moa
- inhibition of metabolic reactions
- sulfonamides
- inhibition of cell wall synthesis
- penicillin
- modification of cell membrane permeability
- polymixin
- inhibition of protein synthesis
- rifamycin
antimicrobials can be bacteriostatic or bacteriocidal, what are each of these
- Bacteriostatic - inhibits growth and replication, allows body’s immune system to fight infection
- Bacteriocidal - kills bacteria
which groups of drugs exhibit bacteriocidal activity
those that act on the cell wall or cell membrane
which groups of drugs exhibit bacteriostatic activity
those that inhibit protein synthesis or metabolic reactions
when can bacteriostatic drugs be bactericidal
at high doses
True/False: Bacteria synthesize folate, mammals do not
true
which group of drugs is responsible for inhibition of metabolic reactions in cells
Anti-metabolites
what is the selective toxicity of anti-metabolites
absence of biological reactions
what are some drugs in the antimetabolite group
- sulfonamides
- antifolates
- purine analogues
- pyrimidine analogues
what is the mechanism of action of antimetabolites
- they inhibit metabolic reaction by binding to the site of action
- they mimic the metabolite needed for the reaction
what is folic acid necessary for
syntheis of dna and rna
sulfonamides are the structural analogue of
- PABA
- Paba is a part of folic acid structure
- folic is needed for dna/rna synthesis
competitive antagonist with PABA for hydropteroate synthetase
sulfonamides
what is another antimetabolite and what is it an analogue for
trimethorprim
folate
what are the classes of drugs that inhibit cell wall synthesis (3) and provide example of antibiotic in each category
- beta lactams
- penicillins, cephalosporins
- glycopeptides
- vancomycin
- polypeptides
- bacitracin
how do drugs that inhibit cell wall synthesis work
- cause the cells to swell and burst b/c the medium is hypotonic wrt cell interior
- interfering with cell wall synthesis
how do drugs that modify cell membrane permeability work
slectively bind to plasma membrane causing leakage of phosphate and nucleaosides
e.g. polymixin B and C
how do drugs that inhbit protein synthesis work
- by binding to 30 or 50S subunits of ribosomes preventing protein synthesis
- blocking RNA polymerase
Rifamycin has its selective toxicity in that
it only targets RNA synthesis not DNA synthesis therefore no effect on mammalian cells
what are two drugs that inhibit RNA synthesis
rifamycin
4-quinolones
these drugs act at the 30s ribosome and 50s ribosome
- 30s- aminoglycosides, tetracyclines
- 50s - chloramphenicol, erythromycin
name two types of fungi
- dermatophytes
- yeasts
infect skin, hair, nails
dermatophytes
cause candidiasis
yeast
cause ringworm
dermatophytes
what are three species of dermatophytes that cause infection in man
- tricophyton - nails
- epidermophyton - skin
- microsporum - hair
what is the scientific word for ringworm
tinea
how is ringworm treated
- topically with zinc, benzoic acid and salicylic acid
- using grisefulvin
what is a common infection from yeast
thrush
what is used to treat thrush
nystatin topical or oral
nystatin acts by
causing cell membrane to leak amino acids and glucose causing cell lysis
what is used to treat systemic candidiasis and how does it act
flucytosine
inhibits protein synthesis by binding to tRNA preventing transcription of protien
what are the 4 classes of wide spectrum anti-fungals and what can each treat
- natamycin
- dermatophytes and yeast
- anti-trichomonal
- imidazoles & triazoles
- dermatophytes and yeast and trichomonas
- amphotericin
- deep seated systemic yeast
- echioncandins
- aspergillus and candida
what are som drugs in imadizole/triazole family
- clotrimazole
- econazole
- miconazole
- ketoconazole
- fluconazole
- ticonazole
malaria is a bacterial or protozoal disease
protozoal
how do protozoa differ from bacteria
- single celled
- larger than bacteria
- move by means of cilia or flagella or amoeboid movement
- contain nuclei and mitochondria resembling mammalian cells
what cells are injected from an infected mosquito into humans
sporozoites
where does reproduction of malarial cells occur
in the liver via para-erythrocytic stage
