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85 Cards in this Set
- Front
- Back
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What are the two major groups of Antitubercular Agents?
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Synthetic Antitubercular Agents and Antitubercular Antibiotics
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What are the three major synthetic Antitubercular Agents?
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Aminosalicylic acid, Isoniazid, and ethambutol
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Which synthetic Antitubercular agent has good oral absorption, is distributed into most body fluids but lower levels are in cerebrospinal fluid?
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Aminosalicyclic Acid
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What antitubercular agent helps to increase levels of free Isoniazid?
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Aminosalicylic Acid
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What is the mechanism of action of aminosalicylic acid?
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Aminosalicylic acid works by preventing incorporation of PABA inot the dihydrofolic acid molecule catalyzed by the synthetase.
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Which Antitubercular agent is active on growing tubercle baccili but not on resting forms?
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Isoniazid
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Which antitubercular agent causes a loss of lipid content of the bacilli?
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Isoniazid
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True or False?
Isoniazid is rapidly absorbed and distributed even to the CSF. |
True
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Which anti-tuber agent is metabolized by acetylation of NH2?
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Isoniazid
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Which Anti-tuber agent is only active against dividing mycobacteria, NOT encapsulated forms?
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Ethambutol
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What anti-tuber agent works by inhibiting the incorporation of mycolic acids into cell walls of the mycobacteria?
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Ethambutol
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What anti-tuber agent is stereospecific dependent?
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Ethambutol
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Pyrazinamide, Ethionamide, Clofazimine
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Other Synthetic Anti-tuber Agents
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What are the Antitubercular Antibiotics?
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Cycloserine, vinactins, capreomycins, and rifampin
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What is the mechanism that Anti-tubular antibiotics work by?
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They prevent the synthesis of cross-linking peptides in the formation of bacterial walls.
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What antituber Antibiotic is wide spectrum, most notable active against gram positive bacteria and TB. Most active agent for the treatment of TB.
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Rifampin
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The area of the body that Rifampin is not distributed throughout the body at effective concentrations.
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The Brain
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One of the most potent inhibitors of DNA directed RNA polymerase in bacteria but no activity against the mammalalian enzyme.
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Rifampin
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What two components make up the cell wall?
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The outer membrane and the peptidoglycan layer.
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The peptidoglycan layer is thicker in gram + or gram - bacteria?
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Much thicker in Gram + bacteria.
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Tolbutamide and Furosemide
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Non-Antibacterial Sulfonamides
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How can you tell if a sulfonamide is antibacterial?
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1. Must have H2N free
2. Must have ionizable Hydrogen |
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Inhibit DNA synthesis by competing with PABA
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Antibacterial Sulfonamides
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Antibiotic with similiar mechanism as sulfonamides and used mainly for treatment of Leprosy.
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Dapsone
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A substance that antagonizes the growth of one or more species of microorganisms.
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Antibiotic
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What are the B-lactam antibiotics?
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Penicillins, B-lactamase inhibitors, Cephalosporins, and Monobactams
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Broad spectrum antibiotics that affect cell wall synthesis. i.e. Inhibit the biosynthesis of dipeptidoglycan that is needed to provide strength to the cell wall. Also acylates a bacterial D-trans-peptidase rendering it inactive.
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B-lactam Antibiotics
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What is a reason why penicillins have poor oral absorption?
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pH < 3 leads to rearrangement of the lactam ring. (i.e. in the stomach)
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What are the reasons for penicillin resistence of bacteria?
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B-lactamase and acylase enzymes and decreased permeability to penicillin and altered penicillin binding proteins.
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Can be used in combination with B-lactamase sensitive penicillins.
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B-lactamase Inhibitors
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Clavalanic Acid, Sulbactam, and Carbapemens
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B-lactamase Inhibitors
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Cephalosporins are not synthetic. True or False?
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False. They are semisynthetic.
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What does SAR stand for?
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Structural Activity Relationships
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Where do Cephalosporins have an unsaturation point?
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3-position (CAS)
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Cephalosporins are broad spectrum like penicillins and much more resistent to inactivation by B-lactamases. True or False?
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True
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Monocyclic, highly resistent to B-lactamases, and extensive SAR including side-chain w/ heterocyclic rings.
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Monobactams
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What are the Aminoglycosides?
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Kanamycin, Streptomycin, and Neomycin
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Can be used in combination with Penicillin but not in the same solution as the two are chemically incompatible.
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Aminoglycosides
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What is the Mechanism of Action of aminoglycosides?
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They act on the bacteria ribosomes (30s subunit) to inhibit the initiation of protein synthesis and to interfere with the fidelity of translation of genetic message.
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Very poorly absorbed upon oral administration. Therefore they are good for GI and skin infections.
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Aminoglycosides
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Broad spectrum antibiotic used mainly for serious systemic infection caused by aerobic gram - baccilli. However fairly toxic.
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Aminoglycosides
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Considering Aminoglycosides, ring II is crucial and is primary target for inactivating enzymes. True or False?
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False. Ring I is crucial.
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How are aminoglycosides inactivated?
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Bacterial enzymes that are capable of actylating, phophorylating or adenylating key amino or hydroxyl groups of the aminoglycosides.
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Broadest spectrum antibiotic known.
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Tetracycline
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Is Tetracycline subject to degradation by strong bases only?
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No. It is subject to degradation from strong acids and bases.
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Obtained from streptomyces species or semi-synthetic.
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Tetracycline
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Forms chelate complexes with metals including CA2+, Mg2+, Fe2+, and Fe3+
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Tetracycline
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What antibiotic has a high affinity for Ca2+, such as in milk and in bone?
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Tetracycline
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What is the mechanism of action of Tetracycline?
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Inhibit protein synthesis by binding to the 30s ribosomal subunit and thereby preventing the binding of aminoacyl tRNA to the mRNA ribosome complex.
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Resistence is mainly by efflux.
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Tetracycline
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Erythromycin, Clarithromycin (Biaxin), and Axithromycin
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Examples of Antibacterial Macrolides
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Mechanism of action is binding selectivly to 50s ribosomal subunit to prevent the translocation step of bacterial protein syntheis.
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Erythromycin
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Sulfur containing and binds to 50s ribosomal subunit to inhibit protein synthesis.
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Lincomycins
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Limited to clinical use because of toxicity and lacks systemic activity when used orally.
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Polypeptides
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Production is now systemic and is the only major antibiotic so produced.
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Chloramphenicol
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Is Chloramphenicol cidal or static?
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Bacteriostatic
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Can penetrate the CNS and therefore used for Menigitis.
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Chloramphenical
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Believed to act by inhibition of DNA synthesis by inhibiting bacterial DNA gyrase (topoisomerase II)
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Quinolones
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Urinary tract anti-infective agents
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Quinolones
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Examples of Quinolones
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Quinoline, naphthyridine, and cinnoline
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Obligate cellular parasites composed of a nucleic acid core surrounded by a proteinaceous outer shell.
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Viruses
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The development of site-specific antiviral agents can take advantage of 5 targets.
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1. Attachment of the virus to the surface of the host cell and its penetration into the cell.
2. Release of viral nucelic acid form the protein coat. 3. Replication of the genome and synthesis of viral proteins. 4. Assembly of the virus particle to from virion. 5. Release of the mature virus from the cell. |
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Special class of RNA viruses that possess a RNA-dependent DNA polymerase (reverse transcriptase) that is required for viral replication.
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Retroviruses
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What are examples of Retroviruses?
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HIV and human T-cell leukemia viruses
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What is an example of a DNA virus?
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herpes virus
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They block replication by 3 general mechanisms after getting phosphorylated.
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Nucleoside analogs (see B50 for the 3 mechanisms)
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Examples of the nucleoside drugs are...?
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Idoxiuridine, trifluridine, and Didarabine
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What type of virus does Idoxiuridine work against?
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DNA viruses
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What phosphoylates the nucleosides?
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viral thymidylate kinase
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Mimics deoxyguanosine. Most effective member of a series of acylic nucleosides with antiviral activity.
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Acyclovir
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DOC for genital herpes
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Acyclovir
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How does Acyclovir work?
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It mimics Deoxyguanosine and ends chain elongation
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What type of virus does AZT fight?
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Retroviruses
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Ribavirum, Inosiplex, and Vidarabine
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Other nucleosides
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What type of drug is Adamantadine?
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Non-nucleoside
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How does Adamantane work?
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It blocks penetration and uncoating. Therefore it cannot work once infection has occurred, but it can be used within 48 hours to prevent infection of more cells.
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What is a six-membered cage compound called?
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Adamantanes
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What is adamantane used for?
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Prevention but not treatment of influenza by influenza A virus
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What drug is well absorbed upon oral administration and has a side effect of dopamin release?
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Adamantane
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How many deaths are caused each year from malaria?
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1 million world wide
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What are the ways to treat or prevent malaria infections?
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1. destruction of the vector
2. vaccines 3. drug treatment |
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What are some treatments for malaria?
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Quinoline and analogues, tetrahydrofolate synthesis inhibitors.
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Platyhelminthes and Nemathelminthes
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Two phyla from which helminthes are derived
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Do you know the four mechanisms of action exerted by antihelminthes?
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Yes (but see B56 anyway)
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What are some antiscabious and Antipedicular drugs?
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Benzlbenzoate, Lindane, and Permethrin
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