Drugs For Treating Infection Flashcards
4 main types of microorganisms:
- bacterium
- fungus
- virus
- parasite
What is bacteria?
Single called microorganisms with rigid outer cell wall in addition to the cell membrane
Bacteria is classified by:
- gram straining (gram-positive or gram-negative)
- oxygen requirements
- morphology (shape)
- encapsulation
Name 3 common strains of bacteria:
- staphylococcus
- streptococcus
- bacillus
Name 3 general shapes of bacteria:
- cocci
- rods
- spiral
What is fungi?
groups of organisms that include yeasts and mold
Fungi thrive in what environments?
- moist, dark, warm
- found in superficial keratinized tissues (nails, hair, skin)
What is the most common cause of fungi?
Dermatophytes
Why is the name ringworm misleading?
There is no worm in human ring worms. It’s called ringworm based on what it looks like. Annular (round) plaque.
What is the proper term for ringworm?
Tinea
Where can tinea be found?
- capitals (on the head/scalp)
- pedis (foot, aka athlete’s foot)
- cruris (groin, aka jock itch)
- unguium (finger or toe nails. Can have some cross over with tinea pedis)
- corporis (of the body, otherwise not identified by terms above - mostly shoulders and back)
What is the proper term for yeast infections? Where is it typically found?
- candidiasis
- can be in tongue, throat, genitals etc.
- most common in the mouth, associated with people who use corticosteroid inhalers (makes them susceptible to oral candidiasis, aka thrush)
Why is it debated whether viruses are a living agent?
Because it cannot live without a host cell
What is a virus?
- ultramicroscopic organisms that require host cells
- virus will reproduce, at the expense of the host cells
Give examples of viruses.
- covid
- mononucleosis
- influenza
- cold
- measles
- herpes
- hepatitis
- Ebola
- polio
- chicken pox
How can drugs stop viruses?
Most drugs interfere with the virus’ ability to replicate itself
If someone has a viral infection, an _______ will not help them.
Antibiotic
How are antimicrobial agents named?
- “____cidal” vs “____ static”
- ex. Germocidal and germostatic
- ex. Fungicidal and fungistatic
Antimicrobial agents can have ________ vs ________ toxicity.
- selective
- non-selective
Why is it not always ideal for antimicrobial agents to kill the bacteria completely?
If the drug can dampen the effects and the immune system can fight the illness with help, it may be better for the immune system.
What is the main risk with using broad spectrum drugs?
- may kill off good bacteria, causing health issues long term
- selective is ideal so that it does not kill off other cells
Antimicrobial drugs aka…
Antibiotics
4 types of antimicrobial drugs:
- antibacterial
- antifungals
- antivirals
- antiparasitics
What are antiseptics? Give examples.
- substances that can be place on living tissue (organic surfaces) for killing microorganisms or inhibiting growth of such
- ex. Iodine, chlorahexidine
Name some products that can function as both an antiseptic and a disinfectant.
- alcohol (ethyl and isopropyl)
- hydrogen peroxide
What are disinfectants? Give examples.
- used to combat microorganisms but should be applied to non-living objects (non organic surfaces)
- ex. Chlorine, phenyl, bromine, other chemicals
What is antimicrobial resistance?
- Microorganism becomes less sensitive or loses its sensitivity to a previously sensitive antimicrobial
- worst in anti-bacterials. Argument that we are overdoing it. Microbes become capable of overcoming these products
Why does antimicrobial resistance develop?
Develops due to change in genetic make-up of microorganism (spontaneous random mutation, ra safer of genetic material)
Mechanisms of action for antibacterial agents:
- inhibition of cell wall synthesis (most common)
- inhibition of protein synthesis (2nd most common)
- alteration of cell membrane structure
- inhibition of nucleic acid synthesis
- anti metabolic activity
Describe the difference between broad and narrow spectrum of activity.
- broad spectrum: casts a wide net since it is unclear what the infection is while it is being established. Has a better chance of being successful.
- narrow spectrum: very effective for a select few, not for others
Routes of administration for antibacterial agents:
- oral
- intravenous (often when septic or severe)
Issues with oral medication:
- adherence
- disrupting GI tract (diarrhea, stomach upset, vomiting)
- light sensitivity
- some have drug food interactions (esp with calcium)
- heart arrhythmias
- tendon pathologies
Describe pharmacokinetics of antibacterial agents:
- absorption affected by many factors
- distribution via binding to serum proteins
- metabolized in liver
How does penicillin work?
- beta lactam antibiotics (medications have beta lactam ring, which is how it attacks the cell wall)
- inhibit bacterial cell wall synthesis (bacteriocidal)
- inactivated by beta lactamase (can become drug resistant)
- primarily renally excreted
Penicillin is more effective with what type of bacteria?
Actively growing bacteria (acute stages)
How are penicillins named?
- ….icillin
- ex. Amoxicillin, methicillin
Therapeutic uses for penicillins:
Used for a variety of types of infections:
- UTI
- respiratory tract infections
- endocarditis
- ear infections
- syphilis
Which drug is often a first line drug if someone has suspected bacterial infection (unless allergic or has sensitivity)?
Penicillins
Penicillins are generally more effective for gram _____ than gram _____ bacteria.
- gram positive
- gram negative
Adverse effects of penicillins:
Allergic/hypersensitivity reactions:
- symptoms range from skin rash to anaphylaxis
- cross-allergy between penicillins
- prior penicillin exposure required for reaction
Why do many people think they have an allergy to penicillins but it is not a true allergy?
- most of the time it is a hypersensitivity
- often first time exposed to penicillin causes minor immune response. Without getting proper allergy testing, it is hard to determine if it is a true allergy without a second exposure
Cephalosporins are very similar in structure and action to _________.
Penicillin
What are cephalosporins?
- beta-lactam antibiotics
- inhibit bacterial cell wall synthesis
- bactericidal
- inactivated by beta-lactamase
- less drug resistance to cephalosporins than there is to penicillin
- primarily renally excreted
If someone is allergic to penicillins, can you give them cephalosporins?
- rare to have a cross allergy. Enough difference from penicillin that is unlikely that you will have an allergy to both.
- if person had severe allergic reaction to penicillin, cephalosporins may also be avoided
What are the different classes of cephalosporins?
- 5 generations (evolved drugs). Different generations are better at different things
- antibacterial spectrum is broader as generation increases
- starts with gram-positive coverage and adds gram-negative coverage
- more resistance to beta-lactamase
How are cephalosporins named?
Cef/ceph/kef….
What are tetracyclines?
- inhibit bacterial protein synthesis
- bacteriostatic
- broad spectrum
- names ….cycline
Why are tetracyclines used less commonly than decades ago?
- lots of side effects
- drug resistance
Therapeutic uses for tetracyclines:
- certain infectious diseases (ex. Rocky Mountain spotted fever, Lyme disease, pneumonia caused by mycoplasma pneumoniae)
- acne (can be topical or oral)
- peptic ulcer disease
Drug and food interactions of tetracyclines:
- bind to minerals
- calcium, iron, magnesium, etc.
- dairy products, supplements, laxatives, antacids
- give 1 hour before or 2 hours after (decreased adherence)
Adverse effects of tetracyclines:
- tooth discolouration (yellow or grey. Can also happen in-utero or in kids)
- altered bone development
- GI
- photosensitivity (important to use sunscreen, sunglasses. Susceptible to skin or eye damage)
Who should not take tetracyclines?
- children younger than 8 years
- pregnant or nursing women
What are macrolides?
- inhibitors of protein synthesis
- bacteriostatic
- spectrum of activity similar to penicillins (works on similar bacterial infections, often substituted when penicillin is not an option)
- resistance
- …mycin
Adverse effects of macrolides:
- most common are GI
- epigastric irritation, diarrhea, nausea, vomiting
- can be reduced by taking with food, but it impacts absorption of drug
What are sulfonamides?
- aka sulfa drugs
- broad spectrum
- bacteriostatic
- systemic vs topical
Sulfonamides may be mixed with silver for what purpose?
Burn care for serious wounds to promote healing and fight infections in deep MSK tissue.
Uses for sulfonamides:
UTI (most common)
Adverse effects of sulfonamides:
- renal damage
- allergy/hypersensitivity
- increased free concentration of bilirubin
Sulfonamides should not be used in what populations?
- infants
- near-term pregnant women
- nursing mothers
What are fluoroquinolones?
- relatively newer antibiotic
- started getting used to treat anthrax where nothing else worked
- broad spectrum
- bactericidal (kills bacteria)
- inhibit bacterial DNA synthesis
- penetrate into many tissues
- …floxacin (most common: ciprofloxacin)
Why is fluoroquinolones considered a hammer?
Can work where other medications do not
Why shouldn’t fluoroquinolones be used as a first line defence?
There are severe cases of side effects
Adverse effects of fluoroquinolones:
- risk of tendon problems when taking the drug and shortly after. Risk increased in those over 60, substantially more significant if they are on corticosteroids (esp injectable) at the same time.
- phototoxicity
Fluoroquinolones are not recommended for which populations?
- children younger than 18 years old
- pregnant women
If someone develops signs of ______ while taking fluoroquinolones, it should be discontinued.
Tendinopathy
Food and drug interactions with fluoroquinolones:
- similar to tetracyclines
- bind to minerals
- calcium, iron, magnesium etc.
- dairy products, supplements, laxatives and antacids
- give 1 hour before or 2 hours after
Pros and cons of using topical antibiotics:
- wide range of conditions benefit from topical antibiotics
- reduce infection rate
- excessive use promotes resistance, hypersensitivity, impedes wound healing
- wounds heal faster covered in a occlusive dressing and with topical antibiotic until it stops seeping.
- some people may react to it
Name 3 topical antibiotics and what type of bacteria they work on.
- bacitracin: gram-positive bacteria
- neomycin: gram-negative and some staphylococcus species. Higher rate of allergic skin reactions
- polymyxin-B: gram-negative bacteria
Antifungals are available in what forms?
- available in topical, suppository and oral preparations
- topical preparations sometimes combined with cortisone
- …fine, …azole
For fungal skin infections, _______ is the best medicine.
Prevention
Describe antivirals:
- narrow spectrum
- mechanism of action varies by agent
- resistance
- wide range of adverse effect potentials
- oral, parenteral, and topical therapies
Important patient education for drugs that treat infections:
- may experience abdominal pain, nausea/vomiting, diarrhea
- extended release needs to be swallowed whole, not split or broken
- doses should not be skipped
- photosensitivity associated with select antibiotics
- overuse promotes development of resistant strains (especially broad-spectrum antibiotics)
- superinfections
- up to half of antibiotics are unnecessary, poor choices, dosed wrong, or ineffective (viral infection)
Red flags (contact provider) to look out for in those taking drugs for treating infection:
- tachycardia or abnormal heartbeat; syncope
- difficulty breathing
- hearing or vision changes
- dark urine, light-colour stools, jaundice
- diarrhea and fever
