Block 8 Flashcards
(161 cards)
Which anti-TB agent is able to inhibit membrane-bound ATP synthase and block ATP production in mycobacteria?
Bedaquiline
Define the MOA of thiazide diuretics.
They affect the distal renal tubular mechanism of electrolyte absorption –> they reduce the amount of salt and wter in the body by reducing tubular reabsorption
How do polyene antifungal agents work?
They are membrane disruptors
- they are the broadest spectrum antifungals
- MOA: bind to ergosterol and form pores (making the membrane leaky); affinity for ergosterol > cholesterols
** the number of double bonds directly correlates with fungal toxicity and selectivity
Which NA inhibitor is a prodrug that is orally active? How is it activated to its active form and what is that active form?
Which one is given via inhalation?
Which one is given by IV?
Oseltamivir - orally active prodrug; cleaved by esterase to active drug (oseltamivir carboxylate)
Zanamivir - inhalation
Peramivir - IV
What are the primary and secondary insults associated with NSAIDs and gastric damage?
Primary - direct acid damage, an indirect contact effect, and a back diffusion of hydrogen ions
Secondary - inhibition of PG biosynthesis in the GIT, where PGs exert a cytoprotective effect (COX1 inhibition)
What is the purpose of the drug Kionex (polystyrene sulfonate)?
Identify its MOA.
Controls potassium levels
MOA - as the resin passes along the intestine or is retained in the colon after administration by an enema, the sodium ions on the molecule are partially released and replaced by potassium ions
What is a noticeable structural different between imidazoles and triazoles?
Triazoles have 3 nitrogens in a 5 member ring.
Imidazoles only have 2.
What is unique about triazole function when compared to imidazoles?
they exhibit more selective toxicity and are associated with fewer side effects
What is typically given alongside isoniazid? Why?
Vitamin B6 because INH is an antagonist of it; adding more vitamin B6 to the patient’s diet prevents the side effects associated with the antagonistic activity
identify the MOA of epinephrine.
adrenergic receptor agonist
acts on both alpha and beta receptors
- alpha activation causes vasoconstriction and decreases vascular permeability that occurs during anaphylaxis
Which two steps (enzymes) in ergosterol biosynthesis can be targeted?
1 - squalene epoxidase (it’s the last non-cyclic molecule in the synthesis pathway, so by inhibiting this enzyme with allylamine antifungals we can inhibit the first step in producing ergosterol)
2 - P450 14-alpha demethylase (CYP51) (lanosterol is eventually converted to ergosterol by this enzyme, so azole antifungals will prevent synthesis in the final stages)
What are the two drugs that belong to the “aryl and heteroarylacetic acids” category of NSAIDs?
How do they differ?
Diclofenac - most widely used NSAID; is more potent than aspirin in anti-inflammatory and antipyretic properties; MOA is COX inhibition and reduced production of PGs along with inhibition of the lipoxygenase pathway and arachidonic acid release
Nabumetone - prodrug of 6MNA, which is an effective inhibitor of COX in joints; more active than aspirin at inflammation reduction bu 1/2 as potent in analgesic properties; pro - less gastric irritancy
Identify the drug and its MOA.

Montelukast (Singulair)
MOA - high affinity CysLT1 receptor binder, so it inhibits the activity of LTD4 at the receptor
What are important mechanisms to resistance to antifungal agents?
- target alterations
- reduced access to targets
Drugs for herpes are broken down into what 3 categories?
1 - Nucleoside Analogs
2 - Nucleotide Analogs
3 - Pyrophosphate Analogs
Describe the ideal qualities of an antifungal agent.
- broad spectrum activity against a variety of yeast and mold
- fungicidal rather than fungistatic (we want to kill it, not just stop it from dividing because immunocompromised people still won’t be able to kill it off themselves)
- selectivity for fungal vs. human cells
- multiple delivery methods (particularly oral availability) to enable prolonged out-patient care
- minimal side effects/toxicities
- essential to identify biological targets that are unique to fungi!
Core structures of nucleoside-guanosine analogs contain _____________ instead of ____________.
What is required for activity of this drug class? Why is this important?
Acyclic side chain instead of a ribose sugar
They have to undergo phosphorylation by a viral kinase for activity –> meaning this class is relatively nontoxic because they cannot be activated in uninfected host cells
The four types of asthma therapeutic agents are:
Adrenergic Agonists (alpha and beta)
Antimuscarinics
Adrenocorticoids
Leukotriene Modifiers
Match each drug with the appropriate description:
acyclovir, ganciclovir, foscarnet, cidofovir, oseltamivir, zanamivir
1 - this drug is administered by intravitreal injection to treat CMV retinitis
2 - a pyrophosphate analog which does not require activation by viral kinase
3 - an obligate DNA chain terminator
4 - is a nucleotide analog
5 - drugs of choice in ganciclovir resistant CMV as well as acyclovir resistant HSV
6 - orally effective prodrug used against flu virus
1 - Ganciclovir
2 - Foscarnet
3 - Acyclovir
4 - Cidofovir
5 - Foscarnet and Cidofovir
6 - Oseltamivir
How do corticosteroids reduce mucus secretion?
They inhibit the release of secretagogue from macrophages. They also inhibit the late phase reaction by inhibiting the inflammatory response and interfering with chemotaxis
How do PDE inhibitors help with COPD?
They increase cAMP and cGMP levels in cell types associated with release of inflammatory chemicals (such as T cells, B cells, monocytes, neutrophils, and eosinophils)
(COPD is associated with neutrophils)
What characteristics are needed for a good topical antihistamine?
- slow rate of receptor dissociation (long duration of action)
- logD ~1.0 +/- 0.5 at pH 7.4 (drugs with logD in this range are most efficacious and their water-soluble salts also show a low incidence of causing ocular irritation)
Give an example of a non-selective NSAID and its therapeutic benefits.
Salicylic Acid
Benefits: antipyretic, analgesic, and anti-inflammatory properties, promotes the excretion of uric acid (gouty arthritis); inhibits COX in platelet membranes, so irreversibly blocks formation of TXA2
Why can COX inhibitors be useful against fungi?
mPGES = microsomal PGE2 synthase (only in fungi)
COX inhibitors prevent the formation of PGE2, so COX inhibitors may reduce the activity that produces biofilms


























