Anti-infections Flashcards
side effect related to antibiotics for children and how they are handled.
If the reaction was not severe, treat adrs by symptoms. For example is the medicine caused an increase risk of sunburn, apply sunblock. If the medicine causes diarrhea add a probiotic to assist with normal flora of the gi tract.
Choice of antibiotics for pregnant patients: what are the safer as in Class A Class B
Azithromycin and erythromycin are Pregnancy Category B, and are considered safe to use during pregnancy
Cross sensitivity with sulfonamides
Risk of cross-allergy with thiazide diuretics, loop diuretics, and sulfonylureas and even some sunscreens with PABA.
Cephalosporins
Cephalosporins are beta-lactam antibiotics, structurally and chemically related to the penicillins. Cefoxitin and cefotetan are actually cephamycins, and loracarbef (no longer available in the United States) is a carbacephem, but they are usually included with the cephalosporins because of their clinical and chemical similarity. The cephalosporin class of drugs is divided into five generations, based on the order of development and spectrum of antibacterial activity. The generations are grouped based on chronology of drug approval, not spectrum of activity or clinical utility. As such, the usefulness of the generation nomenclature is limited; however, their use continues to be pervasive.
Cross sensitivity with antibiotics
Cephalosporins have a 15% chance of cross-sensitivity of allergy in people who have had pcn allergy. Avoid cephalosporins in pcn anaphylaxis. Use cautiously with warnings about possible allergy to cephalosporins in a pcn, with perhaps just a rash.
Cephalosporins list
First generation Third generation
cefadroxil Cefdinir
cefazolin (surgical prophylaxis) Cefpoxime
cefaclor ceftazidime
cefotetan Ceftibuten
cefoxitin Ceftriaxone
cefprozil Cefepime
cefuroxime
Loracarbef
Cephalosporins contraindications
may produce hypersensitivity reaction in a small percentage of patients. Cross-sensitivity with pcn. People who have had type 1 (immediate, anaphylactic) reaction to pcn not recommended. Renal function impairment significantly affects the half life of cephalosporins. Dose adjustments are recommended for most oral agents is GFR less than 30ml/ min. Contraindicated in severe hepatic impairment. instead of ceftriaxone- use cefotaxime. Pregnancy class B, however, given on risk/benefit. Cefotetan reaches therapeutic levels in cord blood. Most cephalosporins are excreted in breast milk. Cefdinir has not been detected in breast milk.
Children and Cephalosporins
Cefazolin, cefotaxime, cefaclor- not recommended for less than 1 month
cefopodoxime not recommended less than 2 months
cefuroxime, cefoxitin not recommended less than 3 months
Cefdinir, cefixime, cefprozil no recommended less than 6 months
Cefditoren not approved for use in children younger than 12 years.
Cephalosporins ADRs
Type 1 allergic reactions, serum sickness-lie reaction, erythema multiforme, other skin rashes, arthralgia, fever.
Type 3 delayed reaction occurs following second course of therapy my be delayed up to 10 or more days. (antihistamines/corticosteroids help manage symptoms). Parental cephalosporins containing a particular chemical group including cefotetan- coagulation abnormalities. Several parenteral are associated with induction of seizure activity, especially with renal impairment. Immune hemolytic anemia in rare instances 2-3 weeks. Bacterial or fungal overgrowth of nonsusceptibility organisms with continued use. Cdiff, liver injury, bloody diarrhea, pulmonary infiltrates with eosinophilia. Ceftriaxone has caused accumulation of biliary sludge or pseudolithiasis.
vaginal itching or discharge, sore mouth or throat, white patches on mucus membranes of mouth, easy bruising or bleeding, altered uop., yellow skin/eyes, lethagy after drug stated, skin rash, aching joints, hives, respiratory problems, false positive on urine testing for glucose, anorexia, epigastric pain, n/v
monitoring cephalosporins
clinical, microbiological, and laboratory data.
diarrhea is common/must be distinguished from cdiff
hemolytic anemia (weakness, tiredness, yellow skin/eyes require RBC
Older patients dose based on renal function-BUN/Creatinine
Patient receiving protracted course of cefotetan require baseline and periodic assessment of PT/also observe for abdominal cramping, facial flushing, headache, hypotension, palpitations, sob, seating, tachycardia, vomiting if exposed to alcohol. (acute disulfiram)
cephalosporins pt education
complete entire course
IM may be irritating and painful
inject deeply into large muscle mass/ avoid repeat im by IV therapy
take with food or milk to avoid stomach irritation/except ceftibuten(empty stomach)
Cefpodoxime proxetil take with food to enhance absorption
Suspensions and antibiotic solutions shake well
PCN
Beta-Lactams
four member ring beta-lactam ring; joined to 6-aminopenicillanic acid
bactericidal against most organisms when concentrations exceed minimum inhibitory concentration (MIC)
hinder bacterial growth by inhibiting the biosynthesis of a bacterial cell wall mucopeptide.
Penicillin V (oral) procaine penicillin (im) benzathine penicillin (im) penicillin G (IV)
active against aerobic, gram-positive organisms including streptococcus species S. pneumoniae, group A beta hemolytic streptococcus, enterococcus strains, and some non-penicillinase-producing staphylococci.
Staphylococcus aureus-only 5-15 % remains susceptible, majority of strains produce penicillinase.
PCN resistance and activity against organisms
pcn resistant strains are also commonly resistant to cephalosporins, macrolides, sulfonamides, clindamycin. There for called drug-resistant S.Pneumonia (DRSP).
PCN has reliable activity against: Pasteurella multocida, actinomyces, clostridium, Pepto streptococcus, treponema pallidum
Pcn G reliable for treating listeria monocytogenes, no longer listed as active against Neisseria gonorrhoeae or against staphylococcus species that are resistant.
Penicillinase-producing organisms have reduced the breadth or organisms this group can treat.
aminopenicillins
reliable activity against gram-positive organisms
including streptococcus, enterococcus species.
greater activity against gram-negative bacteria because of their enhanced ability to penetrated he outer membrane of these organisms. Ampicillin and amoxicillin are the only two available aminopenicillins. Because of the increasing beta-lactamase production among gram-negative pathogens and anaerobes. Ampicillin and amoxicillin are often combined with beta-lactamase inhibitors clavulanic acid and sulbactam to enhance gram-negative and anaerobic activity.
Ampicillin/sulbactam
amoxicillin/ clavulanate
have excellent activity against methicillin-susceptible Staphylococcus aureus (MSSA), Streptococcus, and Enterococcus species, Moraxella catarrhalis, Hemophilus influenzas, Neisseria meningitides, Salmonella, some Shigella species, Pasteurella multicida , Actinomyces, Clostridium, Pepto streptococcus, Bacteroides fragilis.
Susceptible against other gram-negative organism such as Escherichia coli, Klebsiella, Proteus mirabilis has decreased in recent years leading to these agents no longer being recommended for empiric therapy diseases with these organisms.
Nafcillin
oxacillin
dicloxacillin
anti-staphylococcal penicillin
unique spectrum of activity
chemical modifications of pcn yielded this class of antibiotics that is stable in the presence of penicillinase produced by staphylococci. However, activity was eliminated for Enterococcus, listeria, gram-negative bacteria, and most anaerobes. They are active against Streptococcus species, MSSA, some coagulase-negative staphylococci, Pepto streptococcus.
antipseudomonal penicillins
piperacillin combined with a beta-lactamase inhibitor, tazobactam. Piperacillin/tazobactam has enhanced activity against gram-negative bacilli, particularly pseudomonas aeruginosa, Enterobacter, Morganella, Escherichia coli, klebsiella species, proteus mirabilis.
It retains activity against ampicillin-sulbactam-susceptible organisms. Only available for iv in us.
All form of penicillin’s resistance
due to inactivation by beta-lactamases
alteration in targe PBPs on the bacterial cell wall
alteration the outer membrane of cell wall that decreases permeability to the sit of action.
Beta-lactamase production
Most common mechanism.
large group of enzymes: penicillinases, cephalosporinases, carbapenemases.
Produced by S. aureus and Hemophilus species have narrow specificity for pcns.
Beta-lactamase inhibitors
clavulanate
sulbactam
tazobactam
minimal antibacterial activity but irreversibly inactivate beta-lactamase enzymes produced by bacteria by binding to their active site and protecting the antibiotic from inactivation.
Enterobacteriaceae: E coli, Klebsiella species, Enterobacter species extended-spectrum beta-lactamases (ESBLs) that have broader specificity and will hydrolyze both pcns, cephalosporins while sparing carbapenems.
ESBLs
not inhibited by commercially available beta-lactase inhibitors.
Penicillin precautions and contraindications
most likely antibiotics to cause an allergic reaction
A history of serious hypersensitivity reaction (anaphylaxis, serum sickness, exfoliative dermatitis, hemolysis, blood dyscrasia) contraindicates use of any penicillin because of cross-reactivity.
piperacillin may induce hemorrhagic manifestations/caution with anemia, thrombocytopenia, granulocytopenia, bone marrow depression
pregnancy category B, but there are not enough adequate controlled studies in women.
excreted in low concentration in breast milk causing diahrrhea, candidiasis, or allergic response in infant.
Dose adjustment may be required for infants/underdeveloped renal funtion.
contraindication to use pcn based of cephalosporins reactivity
severe type 1 allergic reactions to cephalosporins, carbapenems, or beta-lactamase inhibitors may contraindicate use of pcn, because of cross-sensitivity.
pencillins ADRs type 1
serious/occasional fatal immediate hypersensitivity (anaphylactic shock) 2-30 minutes/n/v, urticaria, pruritus, tachycardia, severe dyspnea, diaphoresis, stridor, vertigo, eventual loss of consciousness and circulatory collapse. epi, antihistamines, corticosteroids skin rashes, serum sickness like (skin rash, join pain, fever) exfoliative dermatitis (red, scaly skin) blood dyscrasias (hemolytic anemia, neutropenia, leukopenia)
A pruritic, maculopapular, measles like, generalized rash with pcns
does not represent a true allergy occasionally occurs with amoxicillin and ampicillin
7-10 days after initiation of therapy remains a few day to a week after med dcd.
pcns ADRs
n/v, diarrhea, epigastic distress
take amoxicillin with food
hepatotoxicity
cdiff (metronidazole, oral vanc, or fidaxomicin required treatment)
PCNs and HIV patients
more susceptible that HIV negative patients to hepatotoxicity (interstitial nephritis)resulting from dicloxacillin, nafcillin, oxacillin.
Pipercillin/tazobactam when combined with vanco leads to higher rates of nephrotoxicity. Pipercillin associated with platelet dysfunction.
High dose procaine pcn G transient mental disturbances, combativeness, irritability, hallucinations
irritability and seizures have occurred with high doses of all pcns especially patients with renal insufficiency.
Choice of antibiotics for pregnant women and breastfeeding women
Azithromycin and erythromycin are pregnancy category B and are considered safe to use during pregnancy.
Clarithromycin should not be used during pregnancy
Azithromycin, erythromycin, clarithromycin are compatible with breastfeeding.
Monitoring pcns
during parenteral therapy, periodic bun, creatinine clearance should be determined especially with agents from pcn resistant group or the antipseudomonal group.
