what is the purpose of an antibiotic
to stop a bacterial infection (bacteriostatic or bactericidal action)
what is the name of the layer specific to bacteria cell walls
peptidoglycan, made of cross linked polysaccharides and polypeptides
difference between gram positive and gram negative bacteria
- Positive
○ Thick peptidoglycan layer and no outer membrane- Negative
○ Thin peptidoglycan layer and an outer membrane
- Negative
what antibiotics are cell wall inhibitors
penicillins and cephalosporins
mechanism of action of penicillins
- Related to D-alanyl-D-alanine, a chemical necessary for formation of cell walls in bacteria, therefore it interferes with the building of cell walls
- Humans don’t have cell walls so only toxic to bacteria
what antibiotic is a DNA synthesis inhibitor
fluoroquinolones
how do the protein synthesis inhibitors work
tetracyline: bind to 30S subunit of mRNA to prevent addition of amino acids - prevent charged tRNA from binding
Macrolides: bind to 50S subunit and prevent peptide bond formation
what to metabolic inhibitors do
antifolates inhibit folate metabolism in bacteria - terahydrofolic acid is necessary for bacterial growth and these stop that from forming
causes of antibiotic resistance
over-prescription
inappropriate use
use in agriculture
how do organisms become resistant
- Uptake
○ Mutation or lack of pores in membrane to allow things to pass through can make the organism resistant- Target
○ A mutation to this can affect binding, making the antibiotic ineffective - Inactivation
○ Some microorganisms develop and enzyme that inactivates the antibiotic - Efflux Pumps
○ Over express transporters that pump the drug out of the cell before it can cause harm
- Target
what are the a antifungal drugs
Echinocandins
○ Cell wall inhibitors
○ Micafungin and capsofungin
○ Tolerated very well in patients
Imidazole’s (Azoles)
○ Inhibit fungal cytochrome P450, inhibiting ergosterol synthesis (critical for cell wall function and survival)
types of antivirals
Oseltamivir (Tamiflu)
○ Treats influenza
○ Neuraminidase enzyme prevents neighbouring cells from being infected
Acyclovir
○ Inhibits viral DNA replication
○ Selective for cells with the virus
○ Herpes
mechanisms of action of hormonal contraceptives
inhibit hormone release
inhibit sperm migration
inhibit ovum plantation
types of oral contraceptives
fixed combination
multiphasic: better for adverse effects
progestin only
mild and moderate effects of oral contraceptives
mild: nausea, headaches, edema
moderate: breakthrough bleeding, weight gain, increased skin pigmentation (due to estrogen), acne and hirsutism (the progestin is believed to cause these two responses, as some of them have androgenic properties), and increased vaginal and uterine infections.
Non-Contraceptive Benefits of Oral Contraceptives
Reduced risk of ovarian cysts.
* Reduced risk of ovarian and endometrial cancer.
* Reduced incidence of ectopic pregnancy.
* Less iron deficiency anemia, as menstrual flow is reduced.
* Less acne and hirsutism (for those containing newer progestins with less androgenic effects).
what do IUDs commonly release
levonorgestrel
guidelines for the selection of appropriate OTC drugs include
proven efficacy and known toxicity
simple formulations and ingredients
comes in the appropriate dosage form
what are the benefits of aspirin
relieves pain, is an antipyretic, and inflammation (tylenol is not antiinflammatory)
low doses prevent stroke and heart attack
inhibits synthesis of prostaglandins
what are prostaglandins
substances that enhance the mediation of pain, fever, and play a role in inflammation
what is the mechanism of action of acetaminophen (tylenol)
Inhibits prostaglandin synthetases which are enzymes that form prostaglandins
describe antihistamines
- Block histamine receptors to decrease allergy symptoms
- First generation
○ Cause sedation and drowsiness - Second generation
○ Less sedating and are the preferred agents
- First generation
what are the 3 kinds of meds that help with excess stomach acid
antacids: Chemically neutralize acid in the stomach
H2 receptor antagonists: reduces amount of acids excreted
proton pump inhibitors: ○ Bind to proton pump and inhibit acid secretion by 90% or more
the different types of cough suppressants
- Centrally Acting Cough Suppressants
○ Block processing of information in the brain, reducing the frequency of the cough
○ Some contain codeine
○ Dextromethorphan hydrobromide (Hbr)- Peripheral Cough Suppressants
○ Block the nerve endings in the throat and bronchioles, inhibiting the stimulus to cough
○ Camphor and menthol are added to vaporizers
- Peripheral Cough Suppressants
