Q: What are the four important questions to answer before prescribing an antibiotic? A: 1. Disorder is caused by infection. 2. Infection is a threat to patient. 3. Infection is sensetive to drug. 4. Appropriate route of administration. Q: What four characteristics are important when proposing a drug: A: 1. effectiveness. 2. toxicity 3. spectrum 4. expense. Q: Patient factors to consider when prescribing a drug? A: 1. History of clinical illness. 2. Ongoing pathologies. 3. Immune system status. Q: What are two exceptions to the rule that one should wait for organism culture before beginning antibiotic therapy? A: 1. Gross appearance of infection is sufficient to diagnose. 2. Serious infection. Q: Should one always culture as a backup, even if one has begun broad-spectrum therapy? A: Yes, always culture as a backup. Q: What does MIC stand for? A: Minimum Inhibitory Concentration, important in determining drug sensitivities of the organism. Q: Should "overkill" drug concentrations be used in therapy? A: Yes, because actual MIC at site of infection is unknown, high concentrations are bacteriocidal rather than bacteriostatic, and it discourages resistance. Q: How is antibiotic treatment initiated? A: ASAP and at the largest possible dose. Q: How long after infection symptoms end should a patient continue treatment? A: At least two days. Q: For what two reasons should one monitor drug concentrations? A: 1. As a guide to dose. 2. To mimimize intoxication. Q: What two distribution principles should be considered in relation to the blood brain barrier? A: 1. Lipid solubility of the drug. 2. Active transport out to the CSF. Q: What two distribution principles should be considered in relation to urine? A: Resorption and active transport, both of which can concentrate drugs in the urine up to one thousand times. Q: How does an ideal antimicrobial drug effect microorganisms versus host? A: An ideal antimicrobial drug ONLY effects the microorganism, not the host. Q: What is meant by the term broad spectrum antibiotic? A: Drugs that are active against a large number of pathogens of many different types. Q: Is a drug's spectrum of action the same as its useful therapeutic range? A: No. Q: Give 5 reasons why we use a therapeutic agents in combination. A: 1. To improve efficacy. 2. Initial treatment of serious infection. 3. Treatment of mixed infections. 4. Allows use of lower, less toxic doses. 5. Prevent resistance. Q: When might one consider prophylactic antimicrobial therapy? A: Surgery, travel in undeveloped countries, and epidemics. Q: What justifies prophylactic antimicrobial therapy? A: 1. Probability of infection is greater than 5 percent. 2. Drug has high therapeutic index. 3. History of prophylactic succes with drug. Q: What are the four sources of drug resistance mutations and genes? A: 1. spontaneous mutation. 2. transformation. 3. transduction (significant). 4. Conjugation (very significant). Q: How can you reduce the frequency of drug resistant strains? A: Decrease overall frequency of use of drugs. Q: What is cross resistance? A: When a drug resistance mechanism makes an organism resistant to many drugs within a class and possibly across classes. Q: Where is drug resistance most common? A: In the hospital setting. Q: Can hospitals reduce drug resistance by implementing controls through protocol? A: Yes. Q: What are 4 common adverse effects of antimicrobial action? A: 1. Superinfection. 2. Hypovitaminosis. 3. Surge of microbial toxin release. 4. Diarrhea. Q: What type of antibiotic is more likely to result in a superinfection? A: A broad spectrum antibiotic is more likely to result in superinfection than a narrow spectrum. Q: What are two adverse effects of antimicrobial drugs that are independent of drug mechanism? A: Irritation and allergy.