-
What are the first groups of drugs used as antibiotics? And what antibiotics are commonly used?
Sulfonamides.
Commonly used: sulfadiazine, sulfamethoxazole, and sulfisoxazole.
-
What is another name for Bactrim?
sulfamethoxazole/Trimethoprim
-
What is the mechanism of action for Sulfonamides?
- Sulfonamides acts as a bacteriostatic ABT by inhibiting the growth of organisms by preventing bacterial synthesis of folic acid production.
- Sulfonamides don't actually destroy bacteria but inhibits their growth.
- Does not affect human cells or other bacteria but rather bacteria that synthesize their own folic acid.
-
Define bacteriostatic antibiotic?
Antibiotics that do not actually kill bacteria but rather inhibit their growth.
-
Describe the indications for Sulfonamides (especially Sulfamethoxazole/Trimethoprim)
Sulfonamides is a broad spectrum antibiotics and works well against gram-positive and gram-negative organisms.
Sulfametahoxazole/Trimethoprim is commonly used for the TX of UTIs because they achieve a very high conc. in the kidneys, where they are also eliminated through.
-
What are other indications for Sulfamethoxazole/Trimethoprim?
- Also used for growths by organisms such as: Enterobacter species, E.Coli, Klebsiella spp., Proteus mirabilis, Proteus vulgarism, and S. aureus.
- Also used for respiratory infections.
- Also used as a prophylaxis and TX of opportunistic infections of clients with HIV infection, esp. Pneumocystis jirovecii (common cause of HIV pneumonia).
-
What are the contraindications for Sulfonamides?
- Allergy to Sulfonamides (sulfa-allergy)
- Pregnant women at term
- infants younger than 2 months.
-
What are adverse effects of Sulfonamides?
- Blood: agranulocytosis, aplastic anemia, hemolytic anemia, thrombocytopenia
- GI: N/V, diarrhea, pancreatitis, hepatotoxicity
- Integ: epidermal necrolysis, exfoliative dermatitis, Steven-Johnson syndrome, photosensitivity to exposure to sunlight
- Other: convulsion, crystalluria, toxic nephrosis, headache, peripheral neuritis, urticaria, cough, pulmonary infiltrates.
-
What are beta-lactam?
It's a class of ABT that function to inhibit the synthesis of bacterial peptidoglycan cell wall.
-
What are the four subclasses of Beta-lactams?
- Penicillins
- Cephalosporins
- Carbapenems
- Monobactams
-
What are bacteriocidal antibiotics?
Antibiotics that kill bacteria
-
What are the four subgroups/classifications of Penicillins?
- Natural penicillin
- Penicillinase-resistance penicillins
- aminopenicillins
- extended-spectrum penicillins
-
What are the different generic drug names of the subclass Natural penicillins?
- penicillin G (available in injectable form for IV or IM use)
- penicillin V (available in PO form;tablet or liquid)
-
What are the different generic drug names of the subclass penicillinase-resistant penicillins?
- cloxacillin
- dicloxacillin
- nafcillin
- oxacillin
- These are ABT that are stable against hydrolysis by most staphylococcal penicillinases, which are enzymes that normally break down the natural penicillins.
-
What are the different generic drug names of subclass aminopenicillins?
- Amoxicillin
- ampicillin
- These are ABT that have an amino group attached to the basic penicillin structure that enhances their activity against gram-negative bacteria compared to natural penicillins.
-
What are the different generic drug names of the subclass extended-spectrum penicillins?
- piperacillin
- ticarcillin
- carbenicillin
- piperacillin/tazobactam
- These ABT have a wider spectra of activity than other PCN.
- Rarely used by alone. Usually used with other drugs.
-
What are the different kinds of penicillin-beta-lactamase inhibitor combinations?
- amipicillin/sulbactam (Unasyn)
- amoxicillin/clavulanic acid (Augmentin)
- ticarcillin/clavulanic acid (Timentin)
- piperacillin/tazobactam (Zosyn)
-
Describe Penicillins
- First introduced in 1940 from molded bread and fruit.
- Bactericidal
- Kills a wide variety of bacteria
- Produce bacterial capable of destroying penicillins; the enzyme beta-lactamases. This decreases the effectiveness of penicillins, hence the creation of clavulanic acid, tazobactam, and sulfactam.
-
What is the mechanism of action of penicillins?
- Penicillin enter the bacteria via the cell wall
- Inside the cell, they bind to penicillin-binding protein
- Once bound, normal cell synthesis is disrupted
- Resulting in bacteria dying from cell lysis.
- Penicillins does not affect other cells in the body.
-
What are the indications for penicillins?
- Penicillins are used to prevent and treat infections caused by gram-positive bacteria such as:
- Streptococcus spp.
- Enterococcus spp.
- Staphylococcus spp.
-
What are some contraindications for penicillins?
- The only usual contraindication for penicillins is known drug allergy.
- It's very important for nurses to obtain an accurate health hx regarding the type of rxn to PCN.
-
What are some adverse effects of penicillins?
- Allergic reactions (occur in 0.7% p 4% of TX courses) such as: urticaria, pruritus, angioedema.
- Those allergic txn to penicillins also have an increased of allergic rxn to other beta-lactam ABT.
- Cross reactivity between penicillins and cephalosporins is between 1% to 4%.
- The most common adverse effects are GI: N/V, diarrhea, abdominal pain.
-
What drugs interacts with penicillins?
- MANY drugs interact with PCN.
- NSAIDs: it competes for protein binding, resulting in more free and active PCN (may be beneficial.
- Oral contraceptives: Mechanism is unknown, but may decrease the efficacy of the BC
- Warfarin: it reduces vit. K from gut flora, resulting in enhanced anticoagulant effect of warfarin.
-
What are Cephalosporins?
- Cephalosporins can destroy a broad spectrum of bacteria and the ability to kill a bacteria is directly related to the chemical changes made to their basic chemical cephalosporin structure.
- There are five generations:
- Frist generation
- Second generation
- Third generation
- Fourth generation
- Fifth generation
- Each generation is divided according to their antimicrobial activity.
-
What are First Generation Cephalosporins?
- First generation cephalosporins are active against gram-positive bacteria and have limited activity against gram-negative.
- Available in parenteral and oral forms.
- cefadroxil
- cefazolin (Ancef) IV or IM
- cephalexin (Keflex) PO
- cephradine
- Used for surgical prophylaxis and for susceptible staphylococcal infection.
-
What are Second generation Cephalosporins?
- Good gram-positive coverage
- Enhanced gram-negative coverage than first generation.
- cefaclor
- cefprozil
- cefoxitin (Mefoxin)
- cefurozime
- loracarbef
- cefotetan
-
What is Cefoxitin (Mefoxin)
- second generation cephalosporin
- used prophylactically for abdominal and colorectal surgical procedures because it effectively kill intestinal bacteria, including anaerobes.
- Available in IV and IM
-
What is cefuroxime (Zinacef/Ceftin)?
- Two kinds: Cefuroxime sodium (Zinacef) & cefuroxime axetil (Ceftin)
- Zinacef only available in IM (parenteral) form
- Ceftin is only available in PO form but has little antibacterial activity until it is hydrolyzed in the liver to its active form.
-
What are third generation Cephalosporins?
- Most potent group against gram-negative bacteria
- Less active against gram-positive bacteria than first and second generation.
- ceftriaxone (Rocephin) - IM
- ceftazidime (Ceptaz, Fortaz, Tazidime) - IM
- cefotazime - IM
- cefpodoxime - PO
- ceftibuten - PO
- cefdinir - PO
- ceftizoxime - IM
-
What is Rocephin?
- Third generation cephalosporin.
- ONLY given once a day
- available in IV/IM form
- Has a long half life
- Primarily eliminated via the hepatic system
- Easily passes the meninges (therefore given for meningitis)
- Diffuses into the CSF to treat CNS infections.
-
What is ceftazidime?
- Third generation cephalosporin
- Available in IV or IM
- Excellent gram-negative coverage
- Used for difficult-to-treat infections such as psudomonas spp.
- Eliminated by renal instead of biliary route
- Excellent spectrum of coverage
- Resistance is limiting usefulness.
-
What are fourth generation cephalosporins?
- A broader spectrum of antibacterial activity against gram-positive bacteria in comparison to third generation.
- Used to treat uncomplicated UTIs, skin and skin structure infections, and pneumonia.
- Cefepime (Maxipime)
-
What are fourth generation cephalosporins?
- It had a broader spectrum of activity than current cephalosporins
- Newest cephalosporin
- Effective against a wide variety of organisms: MRSA and Pseudomonias spp.
- Available in IM form
- Not yet been marketed.
- Ceftobipriole
-
What are adverse effects of cephalosporins?
- Similar to PCN:
- mild diarrhea
- abdominal cramps
- rash
- pruritus
- redness
- edema
- Has a potential cross-sensitivity with PCN if allergies exist.
-
What are carbapenems?
- It's a subgroup of beta-lactams
- Broadest-spectrum antibacterial action
- Therefore, reserved for complicated body cavity and connective tissue infection in acutely ill patients.
- May cause drug-induced seizure activity, but can be reduced with proper dosage.
- Given parenterally.
- imipenem/cilastatin (Primaxin)
-
What is imipenem/cilastatin (Primaxin)?
- Effects by binding to penicillin-binding proteins, inhibiting bacterial cell wall synthesis.
- Indicated for TX of bone, joint, skin, and soft tissue infections; and many more.
- Cilastatin inhibits an enzyme that breaks down imipenem.
-
What are other antibiotic drugs of carbapenems?
- meropenem (Merrem)
- ertapenem (Invanz)
- doripenem (Doribax)
-
What are monobactams?
- It's a subgroup of beta-lactams
- It's synthetic beta-lactams antibiotics.
- Primarily active against aerobic gram-negative bacteria (E.coli, Klebsiella spa., Pseudomonas spp.)
- Bactericidal
- Parenteral use only
- Used for moderately to severe system infections and UTIs.
-
What are macrolides?
- It's a class of ABT.
- considered bacteriostatic, but in high concentrations may be bacteriocidal to some susceptible bacteria.
- Four main macrolide antibiotics:
- erythromycin (E-mycin, E.E.S., others)
- azithromycin (Zithromax)
- clarithromycin (Biaxin)
- dirithromycin
-
What is the mechanism of action for macrolides?
- Prevent protein synthesis within bacterial cells
- Considered bacteriostatic
- Bacterial will eventually die
- May be bactericidal in high concentrations.
-
What are the indications of macrolides?
- Step infections: streptococcus pyogenes (group A beta-hemolytic streptococci)
- Mild to moderate URI and LRI: Haemophilus influenzae
- Spirochetal infections: Syphilis and Lyme disease
- Gonorrhea, Chlamydia, and Mycoplasma
-
What are other indication for use of azithromycin and clarithomycin?
Recently approved for mycobacterium avium-intracelllar complex infection, which is an opportunistic infection associated with HIV/AIDS.
-
What are other indication for use of clarithromycin?
Recently approved for use in combination with omeprazole for TX of active ulcer disease associated with Helicobacter pylori infection.
-
What are adverse effects of macrolides?
- GI effects primarily with erythromycin: N/V, diarrhea, hepatotoxicity, flatulence, jaundice, anorexia.
- Newer drugs, azithromycin and clarithromycin have fewer GI adverse effects, longer duration of action, better efficacy, and better tissue penetration.
-
What are ketolides?
- It's a class of ABT.
- Better antibacterial coverage than macrolides
- Derived from erythromycin A.
- Active against gram-positive bacteria, including multi-drug resistance strains of S. pneumoniae
- Use is limited because it has been associated with sever liver damage.
- Telithromycin (Ketek)
-
What are Tetracyclines?
- Bacteriostatic drugs that inhibit bacterial protein synthesis by binding to the 30S bacterial ribosome.
- Obtained from cultures Streptomyces.
- Is a natural and semisynthetic ABT
- Stops many function of essential bacteria
-
What does Tetracyclines bind to and what food should be avoided?
- Binds (chelate) to Ca2+ and Mg2+ and Al3+ ions to form insoluble compounds, therefore, should not be taken with:
- dairy products
- antacids
- iron salts
- These reduces the oral absorption of tetracyclines.
-
Why shouldn't Tetracyclines be given to pregnant/lactating women and children under the age of 8 years?
It's not given because it causes discoloration of the teeth if it binds with the calcium in the teeth. This could also be considered as a contraindication.
-
What are the indications for Tetracycline?
- It's has a wide spectrum of activity:
- gram-negative/gram-positive organisms
- protozoa
- mycoplasma
- Rickettsia
- Chlamydia
- Syphilis
- Lyme disease
- Acne
- others
- Demecocycline is also used to treat SIADH by inhibiting the action of ADH.
-
What are the different kinds of Tetracycline?
- demeclocycline
- oxytetracycline
- tetracycline
- doxycicline
- minocycline
- tigecycline
-
What are the adverse effects of Tetracycline?
- Strong affinity for calcium, causing:
- discoloration of permanent teeth and tooth enamel in fetuses and children or nursing infants if taken by the lactating mother.
- May retard fetal skeletal development if taken during pregnancy.
- Alters intestinal flora, leading to: superinfection (overgrowth of nonsusceptible organisms such as Candida), diarrhea, pseudomembranous colitis.
- May also cause:
- vaginal candidiasis
- gastric upset
- enterocolitis
- maculopapular rash
- other effects
-
Define superinfection
- (1) infection occurring during antimicrobial treatment for another infection, resulting from overgrowth of an organism not susceptible to the ABT used.
- (2) a secondary microbial infection that occurs in addition to an earlier primary infection, often due to weakening of the patient's immune system function by the first infection.
-
What are aminoglycosides?
- Natural and semisynthetic ABT
- Produced from Streptomyces
- Has many route of administration but has a very poor PO oral absorption through the GI tract (no PO forms)
- Bactericidal; preventing protein synthesis
- It very potent ABT with serious toxicities requires therapeutic monitoring.
- Kills mostly gram-negative and some gram-positive.
-
What are the different kinds of aminoglycosides?
- gentamicin (Garamycin) - commonly used
- neomycin (Neo-fradin) - available in oral and not IV. used for GI tract. Can also be given as an enema to decontaminate the GI tract before surgical procedures.
- tobramycin (Nebcin) - commonly used
- amikacin (Amikin) - commonly used
- kanamycin
- streptomycin - still used for TB
-
What is the mechanism of action for aminoglycosides?
- Works similar to tetracyclines, in that it binds to ribosomes 30S and prevent the protein synthesis in the bacteria.
- Used synergistically with beta-lactams or vancomycins.
-
Why does the aminoglycosides have postantibiotics effect?
Because aminoglycosides works on the bacteria by gaining access to the ribosomes after the beta-lactams breaks down the cell wall.
-
What is postantibiotic effect?
a period of continued bacterial suppression that occurs after brief exposure to certain antibiotic drug classes, especially aminoglycosides and carbapenems.
-
What are the indications for aminoglycosides?
- Used to kill gram-negative bacteria: Pseudomonas spp., E.coli, Proteus spp., Klebsiella spp., and Serratia spp.
- Often used in combination with other ABT for synergistic effect.
- Used for certain gram-positive infections that are resistant to other ABT.
-
What are adverse effects of Aminoglycosides?
- Can cause serious toxicities:
- Nephrotoxicity (renal damage) evident by urinary casts, proteinuria, elevated BUN and serum creatinine levels. Usually reversible.
- Ototoxicity (renal impairment and vestibular impairment resulting from injury to cranial nerve VIII). Less common and is often not reversible
- Other adverse effects: headache, paresthesia, fever, superinfection, vertigo, skin rash, and dizziness
-
Define nephrotoxicity
Toxicity to the kidneys, often drug induced or manifested as compromised renal function
-
Define ototoxicity
Toxicity to ears, often drug induced and manifesting as varying degrees of hearing loss that is more likely to become permanent than nephrotoxicity.
-
When on Aminoglycosides, what should be closely monitored?
- Renal function (BUN/creatinine level, as well as urine output.
- Monitor therapeutic effect by checking peak & trough 5-7 days while on therapy.
-
When is peak and trough checked?
- Only when patient is on IV ABT TX.
- Trough is to be drawn 1 hour before next dose of IV ABT
- Peak is to be drawn 30 min after IV ABT administration is complete.
-
Why does aminoglycosides possibly cause superinfection?
Because it is broad spectrum ABT.
-
What are Quinolones?
- It is a class of ABT that is very potent bactericidal broad-spectrum ABT.
- Also called flouroquinolones
- Excellent oral absorption comparable to IV injection.
- Effective against gram-negative organisms and some gram-positive organisms.
-
What the different kinds of Quinolones?
- Ciprofloxacin (Cipro) - commonly used to treat with infection below the diaphragm Gram-neg
- norfloxacin (Noroxin) - bad oral absorption.
- levofloxacin (Levaquin) - commonly used
- moxifloxacin (Avelox) - commonly use.
- The last two are referred to as respiratory criminals to treat pneumonia.
-
What is the mechanism of action for Quinolones?
- Bactericidal
- Kills bacteria by altering their DNA, causing cell death.
- Does not affect human DNA.
-
What are the indications for Quinolones?
- Gram-negative bacteria such as pseudomonas
- Respiratory infections
- Bone and joint infections
- GI infection (salmonella)
- Skin and soft tissue infection
- Sexually transmitted diseases
- Used to treat complicated UTIs because have high conc in kidneys and effects gram-negative bacteria.
- Anthrax
-
What are some adverse effects of Quinolones?
- CNS: headache, dizziness, fatigue, depression, restlessness, insomnia
- GI: N/V, diarrhea, constipation, thrush, increased liver function studies, others
- Cardiac: Prolonged QT interval - causes cardiac dysrhytmia when pt are taking disopyramide and amiodarones.
- Integ: rash, pruritus, urticaria, flushing, photosensitivity (with lomefloxacin)
- Others: fever, chills, blurred vision, and tinnitus.
-
What is the black box warning for quinolones?
- Increased risk for tendonitis and tendon rupture.
- Less common in short term tx, but rather longer term care in elderly patients, patients with renal failure, and those receiving concurrent glucocorticoid therapy.
-
What are some interactions with quinolones?
- Anticoagulant should be used with caution with quinolones becuase it affects the vit K synthesis by altering the intestinal flora.
- Nitrofurantoin (macrobid) also interact with quinolones.
-
What are symptoms of superinfection?
fever, perineal itching, unusual discharge, cough and lethargy
|
|