Penicillins extended-spectrum

There are four groups of penicillins natural penicillins, penicillinase-resistant penicillins, aminopeni-cillins, and the extended-spectrum penicillins. See the... 

When used for intraabdominal infection, aminoglycosides should be combined with agents that are effective against the majority of B. fragilis. Clindamycin or metronidazole is the agent of first choice, but others, such as antianaerobic cephalosporins (e.g., cefoxitin, cefotetan, or ceftizoxime), piperacillin, mezlocillin, and combinations of extended-spectrum penicillins... 

Cirrhosis Peritoneal Cefotaxime Regimen based on organism isolated 1. Add clindamycin or metronidazole if anaerobes are suspected 2. Other third-generation cephalosporins, extended-spectrum penicillins, aztreonam, and imipenem as alternatives 3. Aminoglycoside with antipseudomonal penicillin... 

Other Imipenem/cilistatin, meropenem, ertapenem, or extended-spectrum penicillins with B-lactamase inhibitor 1. Ciprofloxacin with metronidazole 2. Aztreonam with clindamycin or metronidazole 3. Antianaerobic cephalosporins.3... 

These agents are generally effective for susceptible bacteria. The extended-spectrum penicillins are more active against P. aeruginosa and enterococci and are preferred over cephalosporins. They are very useful in renally impaired patients or when an aminoglycoside is to be avoided. 

Pseudomonas Cephtazidime, cefepime, imipenem, aztreonatn, ciprofloxacin, aminoglycoside, and extended-spectrum penicillin... 

Other third-generation cephalosporins, extended-spectrum penicillins, aztre-onam, and imipenem as alternatives... 

Antianaerobic cephalosporins or extended-spectrum penicillins are effective in preventing most infectious complications after acute bacterial contamination, such as with abdominal trauma where GI contents enter the peritoneum, and when the patient is seen soon after injury (within 2 hours) and surgical measures are instituted promptly. 

Monotherapy with imipenem 0.5 g IV every 6-8 hours, meropenem 1 g IV every 8 hours, ertapenem 1 g IV every 24 hours, extended-spectrum penicillins with a /3-lactamase inhibitor (piperacillin/tazobactam 4.5 g IV every 6 hours), or tigecycline 100 mg IV as loading dose, then 50 mg IV every 12 hours... 

Complicated coli Proteus mirabiiis Klebisella pneumoniae Pseudomonas aeruginosa Enterococcus faecalis 1. Quinolone x 14 days (B, III)0 2. Extended-spectrum penicillin plus aminoglycoside (B, III)0 Severity of illness will determine duration of IV therapy culture results should direct therapy Oral therapy may complete 14 days of therapy... 

Cystic fibrosis Cystic fibrosis patients have a higher incidence of side effects (eg, fever, rash) when treated with extended-spectrum penicillins (eg, piperacillin, carbenicillin). 

Obstetric infections can be treated with penicillin-beta-lactamase inhibitors such as amoxicillin-clavulanic acid, with extended spectrum penicillins (with or without beta-lacamase inhibitors if justified by local resistance surveillance data), with a first or second generation cephalosporin combined with metronidazole. In severe cases of streptococcal infection high doses of penicillin in combination with clindamycin is the treatment of choice. In amnionitis, maternal morbidity resolves with delivery. In endometritis, antibiotics should be stopped after the... 

Figure 1.6 Number of antibiotic prescriptions per 1000 inhabitants per antibiotic anatomical therapeutic chemical (ATC) classification in 13 European countries in 1997. In parentheses are the ATCs used by the WHO. Tet = tetracyclines, Pen = penicillin, Ex-Pen = extended-spectrum penicillins, B-Lac = (3-lactamase-sensitive penicillins. Cep = cephalosporins, TMP = trimethoprim (alone or in combination), Mac + Lin = macrolides and lincosamides, Mac = macrolides, Lin = lincosamides. Ami = aminoglycosides, and Qui = quinolone. The 13 countries are SP = Spain, GR = Greece, BG = Belgium, PR = Prance, PL = Portugal, IT = Italy, PI = Pinland, UK = United Kingdom, DE = Denmark, AU = Austria, GE = Germany, SW = Switzerland, and NL = Netherlands. (Based on data from Molstad et al., 2002.)...

Chemical Class Penicillin derivative, extended-spectrum p-lactamase inhibitor (tazobactam)... 

Generally replaced by the aminoglycosides or extended-spectrum penicillins for serious infections still used for bladder irrigation and gut decontamination used in combination wit hot her antibiotics and/or corticosteroids topically to treat infections of the eye and skin... 

Extended-Spectrum Penicillins (Ampicillin and the Antipseudomonal Penicillins)... 

Penicillin is rapidly excreted by the kidneys small amounts are excreted by other routes. About 10% of renal excretion is by glomerular filtration and 90% by tubular secretion. The normal half-life of penicillin G is approximately 30 minutes in renal failure, it may be as long as 10 hours. Ampicillin and the extended-spectrum penicillins are secreted more slowly than penicillin G and have half-lives of 1 hour. For penicillins that are cleared by the kidney, the dose must be adjusted according to renal function, with approximately one fourth to one third the normal dose being administered if creatinine clearance is 10 mL/min or less (Table 43-1). 

EXTENDED-SPECTRUM PENICILLINS (AMINOPENICILLINS, CARBOXYPENICILLINS, AND UREIDOPENICILLINS)... 

Cephalosporins are similar to penicillins, but more stable to many bacterial 3 lactamases and therefore have a broader spectrum of activity. However, strains of E coli and Klebsiella species expressing extended-spectrum 3 lactamases that can hydrolyze most cephalosporins are becoming a problem. Cephalosporins are not active against enterococci and L monocytogenes. 

Piperacillin-Tazobactam (Zesyn) [Anribioric/Extended Spectrum Penicillin, Beta Lactamase Inhibitor] Uses Infxns of skin, bone, resp urinary tract, abd, sepsis Action PCN plus 3-lactamase inhibitor bactericidal i cell wall synth Dose Adults. 3.375-4.5 g IV q6h i in renal insuff Caution [B, M] Contra PCN or 3-lactam sensitivity Disp Powder for inj frozen, premix inj 3.25, 3.375, 4.5 g SE D, HA, insomnia, GI upset, serum sickness-like Rxn, pseudomembranous colitis Interactions T Effects W/ probenecid T effects OF anticoagulants, MTX i effects W/ macrolides, tetracyclines i effects OF OCPs EMS T Effects of anticoagulants monitor for signs of electrolyte disturbances and hypovolemia d/t D such as X- K+ may cause allergic Rxn in pts sensitive to PCN OD May cause N/V/D, resp difficulty, and Szs symptomatic and supportive... 

Amoxicillin [Amoxil, Polymox, others] Ampicillin [Omnipen, Polycillin, others] Bacampicillin [Spectrobid] Extended-spectrum penicillins Carbenicillin [Geocillin, Geopen, Pyopen] Mezlocillin [Mezlan]... 

Correct answer a D. Amoxicillin plus clavulanic acid is an extended spectrum formulation that is penicillinase resistant because of the presence of a p-lactamase inhibitor, and is stable in acid. Methicillin, an antistaphylococcal penicillin, is penicillinase resistant but is not stable in acid. Carbeniciliin and piperacillin, antipseudomonai penicillins, are neither penicillinase resistant nor stable in acid. Penicillin V is a narrow spectrum antibiotic that is not penicillinase resistant but is stable in acid. 

Enzymatic inactivation or modification of antibiotics has been discussed by many authors [179-182, 186-188], As described earlier, /(-lactams may be susceptible to /(-lactamases. During the past 30-odd years, several -lactams have been synthesized that are less susceptible to these enzymes. Such drugs include (i) newer types of /(-lactam structures, e.g. carbapenems (37), cephamycins (40) and carbacephems (53), and (ii) modifications of the side-chains of existing penams (38) or cephems (39) [317]. Nevertheless, the wide diversity of /(-lactamases [180,181,318] means that organisms producing enzymes with broad-spectrum activity may be able to resist some members of the /(-lactam group, /(-lactamase inhibitors such as clavulanic acid (36), and the penicillanic acid sulphone (54) derivatives, tazobactam (55) and sulbactam (56) have been combined with, and protect, appropriate /(-lactamase-susceptible penicillins, with useful clinical results. Most extended-spectrum /(-lactamases are susceptible to these inhibitors, but newer -lactamase inhibitors may still be needed. 

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