10.4 Flashcards
Selective toxicity is the ideal, but chemotherapy involves contact with foreign
chemicals that can harm the host:
How many persons taking an antimicrobial drug will experience an adverse side effect?
5%
What is an allergy? what does it act as? how is it provoked? When does sensitization occurs and what can the second exposure lead to?
Heightened sensitivity to a drug
Drug acts as an antigen that stimulates the allergic response
Can be provoked by the intact molecule or by substances that develop from the metabolic alteration of the drug
Allergies have been reported for every major type of drug, but allergy to penicillins is most common.
Sensitization occurs during the first contact with the drug.
Second exposure can lead to hives, respiratory inflammation, or anaphylaxis.
Describe the biota
Normal microbial colonists of healthy body surfaces
Normally consist of harmless or beneficial bacteria
A few may be pathogens
Broad-spectrum antimicrobials destroy healthy biota along with pathogens.
What is a superinfection
microbes that were once small in number overgrow when normal resident biota are destroyed by broad-spectrum antimicrobials
Urinary tract infection caused by E. coli treated with antibiotics:
superinfection
Lactobacilli in the female vagina are killed by the broad-spectrum cephalosporin used to treat the UTI.
Overgrowth of Candida albicans occurs, causing a vaginal yeast infection or oral thrush.
What is antibiotic-associtaed colitis
Oral therapy with tetracyclines, clindamycin, and broad-spectrum penicillins kills off normal biota of the colon.
Overgrowth of Clostridium difficile invades the intestinal lining and releases toxins that cause diarrhea, fever, and abdominal pain.
What is worldwide problem in the management of antimicrobia drugs
Seen as a “cure-all” for infections such as the common cold and acne
In many instances these drugs have no effect or are harmful
Nearly 200 million prescriptions for antimicrobials are written in the US every year.
75% percent of these prescriptions are for pharyngeal, sinus, lung, and upper respiratory infections that are viral in origin.
Physicians have used a “shotgun” approach, using broad-spectrum antimicrobial therapy for minor infections:
Why is this bad?
This has lead to superinfections and other adverse reactions.
Caused the development of resistance in “bystander” microbes (normal biota) that were exposed to the drug as well, leading to the spread of resistant pathogens
Tons of excess antimicrobial drugs in the US are exported to countries where controls are not as strict:
It is common for individuals in Latin America and Asia to self-medicate with antibiotics.
Drugs used in this way are largely ineffectual and lead to drug resistance.
Every allied health professional should be critically aware not only of the admirable and utilitarian nature of antimicrobials, but also their
limitations
