| barriers to drugs | all cell membranes, plasma proteins ability to bind, and the blood/brain barrier |
| Prontosil | a drug that is activated by the liver, when the part of the drug is cut off and made into a sulfa drug. |
| therapeutic index | toxic index/therapeutic dose= 1/1=one dose is toxic and one dose is required to kill the microbe. this proves that there is going to be a toxic to humans with a high frequency of side effects |
| modes of action of antimicrobial drugs | inhibit the cell wall formation, disrup the cell membrane, inhit nucleic acid or folic acid synthesis. |
| inhibit cell wall formation | penicillins, cephalosporins, vancomycin, bacitracin |
| disrupt cell membrane | polymixin B, amphotericin B |
| polymixin B | an antibacterial drug that is put into many topical creams. A detergent which is able to destroy lipids...which can be found on Gram-negative bacteria |
| amphotericin B | an agent that selectively damages the ergoserol found in fungus. The cholesterol of our body is often mistaken for ergosterol and a lot of damage can be caused to our body |
| inhibit protein synthesis | streptomycin, tetracycline, erythromycin, chloramphenical....these are broad spectrum antibiotics |
| inhibit nucleic acid synthesis | quinolones, cipro, rifamprin |
| inhibit folic acid synthesis | sulfonamides, and trimethoprim....these don't affect humans cells because we don't produce this essential vitamin like bacteria do. |
| penicillins | an bacteriocidal drug whose natural form is narrow (acts against gram +) |
| amphicillin | a broad spectrum penicillin |
| methicillin | a penicillinase resistant penicillin |
| Cephalosporin | a bacteriocidal drug that is closely related to the penicillins, they are broad spectrum drugs, although they are particulary effective against the Gram +. They are able to penetrate into the CNS, long persistance in the bloodstream, although they are highly allergenic. people who are allergic to penicillin are most likely allergic to this drug on their first exposure. some specific examples: cephalothin, and cefoxitin |
| Sulfonamides | a bacteriostatic synthetic drug that interferes with the cell's ability to synthesize folic acid. they are broad spectrum. microbial resistance emerged and spread rapidly with extensive use. They cause more allergies and side effects than newer drugs. Now they are generally restricted to treatment of UTI or in combination with another drug. some specific examples: sulfamilamide and sulfamethoxazole |
| Aminoglycosides | a bactericidal drug that acts against gram -. These must be injected and they do not penetrate the CNS. exterely effective against kidney infections caused by gm -. their use is limited because of their toxicity, there is a rapid emergence of drug-resistant strains and is therefore used in combination with another antimicrobially agent |
| chloroamphenicol | a bacteriostatic drug that is broad spectrum and although was initially thought to be great drug, it proved to have rare but lethal side effects. It caused APLASTIC ANEMIA (when the bone marrow completely stops producing blood cells) and can be fatal to infants. This drug is now only used to treat seriously ill hospitalized patients and is not given to infants. |
| tetracyclines | a broad spectrum bacteriostatic drug that interferes with the bacterial protein synthesis. They can cause tooth decay, GI irritation, and rash. It is not to be given to pregnant women, infants, or kids with developing teeth. specific examples include: tetracyline, doxycycline |
| macrolides | a bacteriocidal drug that acts against gram + and causes minimal side effects. When erythromycin is administered it can cause GI pain (crazy diarrhea), but major side effects are rare. commonly used in patients who are allergic to penicillin. some specific examples include: erythromycin, clindamycin, and azithromycin |
| quinolones | a synthetic drug that blocks DNA replication in bacteria. It is broad spectrum. Side effects are minimal, some abdominal pain can occur, and bacteria can become resistant if used too frequently. some specific examples include: ciprofoxacin (drug of choice against anthrax), and nalidixic acid |
| antimycobacterial drugs | Used to treat TB, because of the waxy cell wall it is hard to kill but effective when using multiple drug therapy. Isoniazid can cause liver damage, but rifampin has very few side effects. Rash and fever may occur. |
| nystatin | an fungicidal drug that is used in topical use only. it damages the cytoplasmic membrane, allowing the cell contents to leak out. it interacts with ergosterol. used commonly in vaginal and skin fungal infections. |
| amphotericin B | a fungicidal drug that disrupts the cell membranes. it is used to treat systemic fungal infections. Human cells suffer substantial damage. The this highly toxic drug's side effects include: fever, and kidney damage. This drug is used only in life-threatening situations. |
