The sulfonamides were the first effective
chemotherapeutic agents to be available in safe
therapeutic dosage ranges. They were the main-
stay of therapy of bacterial infections in humans
before the introduction of the penicillins in 1941.
All the sulfonamides are synthetically produced
and contain the para-amino-benzene sulfanila-
mide group. The spectrum of activity for all the
sulfonamides is similar and all are effective against
both gram-positive and gram-negative organisms.
They are primarily bacteriostatic and act as an
antimetabolite (competitor) to para-aminobenzoic
acid (PABA) in susceptible organisms. PABA is
required in the formation of folic acid.
Excretion of the sulfonamides is chiefly
through the kidneys. Some of the sulfonamides
are relatively insoluble in acidic or neutral solu-
tions so there is some danger that a sulfonamide
would precipitate out of solution leading to crystal
formation, hematuria, or possibly renal shut-
down. Forcing fluids to keep the urine dilute or
administering alkaline solutions can help to pre-
vent precipitation of sulfonamides. With the newer
sulfonamides, this is not a major concern since
many of them are soluble in acidic solutions.
Although the sulfonamides have, for the most
part, been replaced with other agents, there is still
a significant demand in certain types of infection,
most notable urinary tract infections, such as
acute cystitis or prostatitis, and in cases of acute
otitis media. The following lists some of the more
ACTION AND USE. This systemic sulfona-
mide is bacteriostatic and is indicated in the treat-
ment of urinary tract infections and acute otitis
USUAL DOSE. 2 to 4 g initially, then 1 to
2 g four times daily for 10 days. The patient
should be advised to increase fluid intake.
Trimethoprim and Sulfamethoxazole
ACTION AND USE. This is an antiinfec-
tive combination used in the treatment of urinary
tract infections and otitis media. Both drugs are
effective antimetabolites but compete at different
steps in the formation of PABA. In combination,
they are more effective than individually.
USUAL DOSE. Two tablets every 12 hours.
The patient should be advised to increase fluid
ACTION AND USE. Sulfacetamide is an
ophthalmic bacteriostatic for the treatment of
conjunctivitis, corneal ulcer, and other superficial
ocular infections. It is available in solutions of
various strengths and in an ointment form.
Sulfacetamide is inactivated by the para-
aminobenzoic acid in purulent exudates.
USUAL DOSE. Solutions of 1 to 2 drops
three or four times daily depending on the severity
of the infection. The ointment should be applied
four times daily.
Silver Sulfadiazine (Silvadene)
ACTION AND USE. Silver sulfadiazine is
a topical antimicrobial agent used in the treatment
of second- and third-degree burns to prevent
wound sepsis. [t is water soluble and easily washed
off the skin.
USUAL DOSE. Silver sulfadiazine is avail-
able in an emollient cream and should be initially
applied to a burn wound twice daily in a sterile
manner. For each dressing change, the burn
wound should be debrided of any dead or
sloughing tissues and carefully cleaned to remove
any residual purulent exudate.
Penicillin is one of the most important of the
antibiotics. It is derived from a number of
Penicilliumm molds commonly found on breads
and fruit. The mechanisms of action for the
penicillins is the inhibition of cell wall synthesis
during the reproductive phase of bacterial growth.
It is one of the most effective and least toxic of
the antimicrobial agents.
Benzylpenicillin (Penicillin G) is the prototype
form for all the penicillins. It is highly effective
against many of the gram-positive cocci, and, to
a lesser extent, the gram-negative cocci. Semisyn-
thetic preparations have been produced to attempt
to overcome some of the problems of the naturally
occurring penicillins, i.e., instability in an acid
medium, rapid renal excretion, susceptibility to
penicillinase, and a high incidence of hypersen-
sitivity. Significant differences among the agents