Appropriate Prescribing of Oral Beta-Lactam Antibiotics

American Family Physician,  August 1, 2000  by Keith B. Holten,  Edward M. Onusko

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TABLE 1

Oral Beta-Lactam Antibiotics

Class                      Drug

Natural penicillin         Penicillin V

Penicillinase-resistant    Cloxacillin (Tegopen)
 penicillin                Dicloxacillin (Dynapen)
                           Nafcillin (Unipen)[*]
                           Oxacillin (Prostaphlin)[*]

Aminopenicillin            Amoxicillin
                           Ampicillin
                           Bacampicillin (Spectrobid)

Beta-lactam-beta-          Amoxicillin-clavulanate
 lactamase inhibitor       (Augmentin)
 combination

Antipseudomonal            Carbenicillin (Geocillin)
 penicillin

First-generation           Cefadroxil (Duricef)
cephalosporin              Cephalexin (Keflex)
                           Cephradine (Velosef)

Second-generation          Cefaclor (Ceclor,
 cephalosporin             Ceclor CD)
                           Cefprozil (Cefzil)
                           Cefuroxime axetil (Ceftin)

Carbacephem                Loracarbef (Lorabid)

Third-generation           Cefdinir (Omnicef)
 cephalosporin             Cefixime (Suprax)
                           Cefpodoxime (Vantin)
                           Ceftibuten (Cedax)

Class                      Antimicrobial spectrum

Natural penicillin         Streptococcus species and oral cavity anaerobes

Penicillinase-resistant    Methicillin-sensitive Staphylococcus aureus
 penicillin                 and Streptococcus species

Aminopenicillin            Same coverage as penicillin V, plus Listeria
                            monocytogenes, Enterococcus species, Proteus
                            mirabilis and some strains of Escherichia coli

Beta-lactam-beta-          Same coverage as aminopenicillins, plus beta-
 lactamase inhibitor        lactamase-producing strains of
 combination                methicillin-sensitive S. aureus,
                            Haemophilus influenzae and Moraxella
                            (formerly Branhamella) catarrhalis

Antipseudomonal            Limited activity against Pseudomonas and
 penicillin                 Klebsiella species

First-generation           Improved coverage of methicillin-sensitive
cephalosporin               S. aureus, E. coli, P. mirabilis and
                            Klebsiella species

Second-generation          Compared with first-generation agents, better
 cephalosporin              coverage of beta-lactamase-producing organisms
                            such as methicillin-sensitive S. aureus,
                            H. influenzae, M. catarrhalis, E. coli,
                            P. mirabilis and Klebsiella species

Carbacephem                Same coverage as second-generation cephalosporins
Third-generation           Variable loss of Staphylococcus and Pneumococcus
 cephalosporin             coverage; compared with second-generation
                           cephalosporins, somewhat expanded coverage of
                           gram-negative organisms; enhanced coverage
                           of Proteus vulgaris and Providencia species

[*]--Poorly absorbed.
TABLE 2

Comparison of Oral Cephalosporins and Penicillins

Factors              Cephalosporins

Allergic reactions   Fewer immediate and delayed hypersensitivity
                      reactions; must be avoided in patients with a
                      history of immediate hypersensitivity to penicillin
Patient tolerance    Better taste, which increases compliance in
                      children; fewer gastrointestinal side effects
Cost                 More expensive
Antimicrobial        Broader antibacterial spectrum
 spectrum

Factors              Penicillin V[*]

Allergic reactions   Allergic reactions common
Patient tolerance    More gastrointestinal side effects
Cost                 Less expensive
Antimicrobial        Narrower antibacterial spectrum;
 spectrum             less likely to induce antimicrobial
                      resistance; some penicillins cover
                      anaerobes, Listeria, Enterococcus
                      or Pseudomonas species

[*]--For purposes of comparison, penicillin V is used as the
prototype penicillin.

Information from references 1, 5, 6, and 9 through 11.
TABLE 3

Selected Differences Among the Oral Cephalosporins

Cephalosporins             Comments

First-generation agents
Cefadroxil (Duricef)       Kinetics allow once-daily or twice-daily dosing;
                            convenience offset by significantly higher cost
                            than other first-generation cephalosporins
Cephalexin (Keflex)        Extensive clinical experience with its use; well
                            tolerated; good pharmacokinetics
Cephradine (Velosef)       Similar properties as cephalexin, but not as
                            widely used
Second-generation agents
Cefaclor (Ceclor,          May cause serum sickness-like syndrome; absorption
Ceclor CD)                  decreased by food; of second-generation
                            cephalosporins, has highest incidence of
                            Haemophilus influenzae resistance
Cefprozil (Cefzil)         Absorption not affected by food
Cefuroxime axetil          Parenteral form available (cefuroxime sodium
 (Ceftin)                   [Zinacef]); absorption enhanced by food; only
                            second-generation agent labeled for the
                            treatment of urinary tract infections
Third-generation agents
Cefixime (Suprax)          Oral suspension better absorbed than tablets
                            (therefore, less likely to cause diarrhea); single
                            oral dose indicated for the treatment of
                            uncomplicated gonorrhea
Cefpodoxime (Vantin)       Of the third-generation agents, provide best
 and cefdinir (Omnicef)     coverage of penicillin-sensitive Pneumococcus
                            and methicillin-sensitive Staphylococcus aureus
Ceftibuten (Cedax)         Poor efficacy against Streptococcus pneumoniae,
                            which limits its clinical usefulness

Information from references 1, 5, 6, and 9 through 11.
TABLE 5

Clinical Indications for Oral Beta-Lactam Antibiotics

Infection             Preferred drug(s)

Otitis media          Amoxicillin
Streptococcal         Penicillin V
 pharyngitis
Sinusitis             Amoxicillin, trimethoprim-
                       sulfamethoxazole
Animal and            Amoxicillin-clavulanate
 human bites
Bacterial             Amoxicillin
 endocarditis
 prophylaxis
Pneumonia             Macrolide antibiotics,
                       quinolone antibiotics
Bronchitis            Doxycycline, trimethoprim-
 (controversial)       sulfamethoxazole,
                       amoxicillin-clavulanate
Skin and soft         First-generation cephalosporins,
 tissue infections     cloxacillin (Tegopen),
 (cellulitis)          dicloxacillin (Dynapen)
Urinary tract         Quinolone antibiotics,
 infection             trimethoprim-
                       sulfamethoxazole

Infection             Alternative drug(s)

Otitis media          Amoxicillin-clavulanate (Augmentin), trimethoprim-
                       sulfamethoxazole (Bactrim, Septra), second-
                       generation cephalosporins, some third-generation
                       cephalosporins, macrolide antibiotics
Streptococcal         In patients with penicillin allergy: macrolide
 pharyngitis           antibiotics, first-generation cephalosporins
Sinusitis             Amoxicillin-clavulanate, second-generation
                       cephalosporins, third-generation cephalosporins
Animal and            Depends on type of bite (e.g., cefuroxime axetil
 human bites           [Ceftin] or doxycycline [Vibramycin] for cat bites)
Bacterial             In patients with penicillin allergy: clindamycin
 endocarditis          (Cleocin), cephalexin (Keflex), azithromycin
 prophylaxis           (Zithromax), clarithromycin (Biaxin)
Pneumonia             Amoxicillin-clavulanate, second-generation
                       cephalosporins, third-generation cephalosporins
Bronchitis            Macrolide antibiotics, quinolone antibiotics, second-
 (controversial)       generation cephalosporins, some third-generation
                       cephalosporins
Skin and soft         Macrolide antibiotics, amoxicillin-clavulanate,
 tissue infections     cefpodoxime (Vantin), cefdinir (Omnicef)
 (cellulitis)
Urinary tract         Amoxicillin, amoxicillin-clavulanate, cefuroxime axetil
 infection             or other cephalosporins, doxycycline, nitrofurantoin
                       (Furadantin)

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