Medication Summary
The goals of pharmacotherapy are to eradicate the infection in order to reduce mortality and morbidity, and to prevent complications. The empiric choice should be based on the overall medical condition of the individual. Because of the progressive increase in the resistance of uropathogens, the local sensitivity profile has become the most important factor in this process (see below [31, 32] ). Anesi et al reported 54% of Enterobacteriaceae UTIs with varying degrees of resistance to extended-spectrum cephalosporins recurred within a median time of 69 days. [33]
Due to the high prevalence of antimicrobial resistance among N gonorrhoeae, it is important to carefully review relevant clinical history of the patient and precisely determine the etiology of urinary symptoms in males. If gonorrhea is suspected, a fluoroquinolone antibiotic should not be prescribed because of widespread resistance by N gonorrhoeae. Dual therapy with ceftriaxone IM/IV plus azithromycin PO is recommended by the CDC sexually transmitted diseases treatment guidelines. [34]
Antibiotics
Class Summary
Empiric antimicrobial therapy must be comprehensive and should cover all likely pathogens in the context of the clinical setting. Below are listed commonly employed antibiotics
Ciprofloxacin (Cipro)
Ciprofloxacin is a fluoroquinolone with activity against pseudomonads, streptococci, methicillin-resistant S aureus (MRSA), S epidermidis, and most gram-negative organisms, but it has no activity against anaerobes. This agent inhibits bacterial deoxyribonucleic acid (DNA) synthesis and growth. Ciprofloxacin is indicated for urinary tract infections (UTIs) and chronic bacterial prostatitis.
Levofloxacin (Levaquin)
Levofloxacin is a fluoroquinolone with better gram-positive activity but less activity against Pseudomonas aeruginosa than ciprofloxacin. This agent is an active L-isomer of ofloxacin. Ciprofloxacin is indicated for complicated and uncomplicated urinary tract infections. It is also used for the treatment of chronic bacterial prostatitis.
Trimethoprim-sulfamethoxazole (Bactrim, Bactrim DS, Septra, Septra DS)
Trimethoprim-sulfamethoxazole (TMP-SMZ) is a combination antimicrobial agent designed to take advantage of synergy between TMP and sulfonamides. The antibacterial activity of TMP-SMZ includes common urinary tract pathogens, except Pseudomonas aeruginosa.
SMZ inhibits dihydropteroate synthetase, preventing incorporation of para-aminobenzoic acid (PABA) into dihydrofolate and subsequent synthesis of tetrahydrofolate. This agent has broad bacteriostatic activity against aerobic gram-positive and gram-negative organisms, with little activity against anaerobes; unfortunately, SMZ does not penetrate well into the kidney.
Ampicillin (Omnipen, Polycillin, Principen)
Ampicillin is an aminopenicillin beta lactam that impairs cell wall synthesis in actively dividing bacteria by binding to and inhibiting penicillin-binding proteins in the cell wall. This agent has enhanced activity against anaerobes and gram-negative aerobes and is generally used in combination with an aminoglycoside for empiric or directed activity against E faecalis urinary tract infections (UTIs).
Amoxicillin (Moxatag, Trimox)
Amoxicillin is a penicillin antibiotic that interferes with the synthesis of cell wall mucopeptides during active multiplication, resulting in bactericidal activity against susceptible bacteria.
Gentamicin (Garamycin, Gentacidin)
Gentamicin is a bactericidal aminoglycoside antibiotic that inhibits bacterial protein synthesis by binding to the ribosome. This agent has activity against a variety of aerobic gram-negative bacteria, as well as E faecalis and staphylococcal species, and it is used with or without ampicillin to treat acute prostatitis in the hospitalized patient when Enterococcus is a concern. Gentamicin is the only aminoglycoside with appreciable activity against gram-positive organisms.
The dosing regimens for gentamicin are numerous. Adjust the dose based on creatinine clearance (CrCl) and changes in the volume of distribution. Ideal body weight (IBW) should be used for calculations (the drug is not fat soluble).
Trough serum levels should be monitored to ensure adequate clearance and reduce toxicity (< 2 mcg/mL). Peak levels should also be monitored after 4-5 half-lives when it is dosed more often than once daily (qd).
Once-daily dosing should only be used when treating gram-negative infections, as this takes advantage of its concentration-dependent killing and its postantibiotic effect. However, gentamicin exhibits neither of these properties against gram-positive infections. (For synergy against gram-positive organisms, use 1 mg/kg q8h).
Tobramycin (TOBI)
Tobramycin is an aminoglycoside used for gram-negative bacterial coverage, with better pseudomonal coverage than gentamicin. This agent is commonly used in combination with agents against gram-positive organisms and those that cover anaerobes.
Consider using tobramycin when penicillins or other less-toxic drugs are contraindicated, when bacterial susceptibility tests and clinical judgment indicate its use, and in mixed infections caused by susceptible strains of staphylococci and gram-negative organisms. Its dosing regimens are numerous and are adjusted based on the CrCl and changes in the volume of distribution.
Ceftriaxone (Rocephin)
Ceftriaxone is a third-generation cephalosporin that has a broad gram-negative spectrum, lower efficacy against gram-positive organisms, and higher efficacy against resistant organisms. By binding to 1 or more penicillin-binding proteins, this agent arrests bacterial cell wall synthesis and inhibits bacterial growth.
Vancomycin (Firvanq, Vancocin)
Vancomycin is a potent antibiotic directed against gram-positive organisms and active against Enterococcus species. It is indicated for patients who cannot receive or have failed to respond to penicillins and cephalosporins or who have infections with resistant staphylococci. It is used in conjunction with gentamicin for prophylaxis in penicillin-allergic patients undergoing gastrointestinal or genitourinary procedures.
Ceftazidime (Fortaz, Tazicef)
Ceftazidime is a third generation cephalosporin and a bactericidal agent that exerts its effect by inhibiting the enzymes responsible for cell wall synthesis. Caution should be used with this agent, as nephrotoxicity has been reported following concomitant administration of cephalosporins with aminoglycoside antibiotics or potent diuretics such as furosemide.
In addition, chloramphenicol has been demonstrated to be antagonistic to beta-lactam antibiotics, including ceftazidime, based on in vitro studies and time kill curves with enteric gram-negative bacilli. Because of the possibility of antagonism in vivo, particularly when bactericidal activity is desired, avoid this drug combination.
Doxycycline (Vibramycin, Vibra-Tabs)
Doxycycline is a broad-spectrum, bacteriostatic antibiotic in the tetracycline class. It inhibits protein synthesis and, thus, bacterial growth by binding to the 30S and, possibly, the 50S ribosomal subunits of susceptible bacteria. It may block dissociation of peptidyl tRNA from ribosomes, causing RNA-dependent protein synthesis to arrest.
Ertapenem (Invanz)
Ertapenem has bactericidal activity from inhibition of cell wall synthesis, which is mediated through ertapenem binding to penicillin-binding proteins. This agent is stable against hydrolysis by a variety of beta lactamases, including penicillinases, cephalosporinases, and extended-spectrum beta lactamases. Ertapenem is hydrolyzed by metallo–beta lactamases.
Aztreonam (Azactam, Cayston)
Aztreonam is a monobactam that inhibits cell wall synthesis during bacterial growth. It is active against gram-negative bacilli but has very limited gram-positive activity and is not useful against anaerobes. It lacks cross sensitivity with beta-lactam antibiotics, and it may be used in patients allergic to penicillins or cephalosporins.
Nitrofurantoin (Macrodantin, Furadantin)
Nitrofurantoin is a bactericidal antibiotic indicated for acute cystitis and UTIs caused by E coli, enterococci, S aureus, and strains of Klebsiella and Enterobacter species.
Rifampin (Rifadin)
Rifampin is an antituberculosis agent that inhibits RNA synthesis in bacteria by binding to the beta subunit of DNA-dependent RNA polymerase, which, in turn, blocks RNA transcription.
Analgesics, Urinary
Class Summary
Urinary analgesics, such as phenazopyridine, can help to treat the symptoms of dysuria.
Phenazopyridine
Phenazopyridine is compatible with antibacterial therapy and can help to relieve pain and discomfort before antibacterial therapy controls infection. It is used for symptomatic relief of pain, burning, urgency, frequency, and other discomfort arising from irritation of the lower urinary tract mucosa caused by infection, trauma, surgery, endoscopic procedures, or passage of sounds or catheters. The analgesic action may reduce or eliminate the need for systemic analgesics or narcotics.
Oxazoiidinone
Linezolid
Epoxide
Fosfomycin
Tetracycline
Minocycline
Cephalasporine
Cefepime
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Prostatic calcifications in a male with a urinary tract infection.
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Bladder calculi in a male with a urinary tract infection.
