Penicillin should be used with caution in individuals with histories of significant
allergies and/or asthma.
Care should be taken to avoid intravenous or intra-arterial admin-istration,
or injection into or near major peripheral nerves or blood vessels, since such
injections may produce neurovascular damage. (See WARNINGS, and DOSAGE
AND ADMINISTRATION sections. ) A small percentage of patients are sensitive
to procaine. If there is a history of sensitivity, make the usual test:Inject
intradermally 0. 1 mL of a 1 to 2 percent procaine solution. Development of
an erythema, wheal, flare, or eruption indicates procaine sensitivity. Sensitivity
should be treated by the usual methods, including barbiturates, and procaine
penicillin preparations should not be used. Antihistaminics appear beneficial
in treatment of procaine reactions.
The use of antibiotics may result in overgrowth of nonsusceptible organisms.
Constant observation of the patient is essential. If new infections due to bacteria
or fungi appear during therapy, the drug should be discontinued and appropriate
Whenever allergic reactions occur, penicillin should be withdrawn unless, in
the opinion of the physician, the condition being treated is life-threatening
and amenable only to penicillin therapy.
In prolonged therapy with penicillin, and particularly with high-dosage schedules,
periodic evaluation of the renal and hematopoietic systems is recommended.
Diarrhea is a common problem caused by antibiotics which usually ends when
the antibiotic is discontinued. Sometimes after starting treatment with antibiotics,
patients can develop watery and bloody stools (with or without stomach cramps
and fever) even as late as two or more months after having taken the last dose
of the antibiotic. If this occurs, patients should contact their physician as
soon as possible.
In streptococcal infections, therapy must be sufficient to eliminate the organism;
otherwise, the sequelae of streptococcal disease may occur. Cultures should
be taken following completion of treatment to determine whether streptococci
have been eradicated.
Pregnancy Category B
Reproduction studies performed in the mouse, rat, and rabbit have revealed
no evidence of impaired fertility or harm to the fetus due to penicillin G.
Human experience with the penicillins during pregnancy has not shown any positive
evidence of adverse effects on the fetus. There are, however, no adequate and
well-controlled studies in pregnant women showing conclusively that harmful
effects of these drugs on the fetus can be excluded. Because animal reproduction
studies are not always predictive of human response, this drug should be used
during pregnancy only if clearly needed.
Soluble penicillin G is excreted in breast milk. Caution should be exercised
when penicillin G benzathine and penicillin G procaine are administered to a
Carcinogenesis, Mutagenesis, Impairment of Fertility
No long-term animal studies have been conducted with these drugs.
(See INDICATIONS AND USAGE and DOSAGE
AND ADMINISTRATION section.)
Clinical studies of penicillin G benzathine and penicillin G procaine did not
include sufficient numbers of subjects aged 65 and over to determine whether
they respond differently from younger subjects. Other reported clinical experience
has not identified differences in responses between the elderly and younger
patients. In general, dose selection for an elderly patient should be cautious,
usually starting at the low end of the dosing range, reflecting the greater
frequency of decreased hepatic, renal, or cardiac function, and of concomitant
disease or other drug thera-py. This drug is known to be substantially excreted
by the kidney, and the risk of toxic reactions to this drug may be greater in
patients with impaired renal function (see CLINICAL PHARMACOLOGY). Because
elderly patients are more likely to have decreased renal function, care should
be taken in dose selection, and it may be useful to monitor renal function.
1. SHAW, E. :Transverse myelitis from injection of penicillin.
Am. J. Dis. Child., 111:548, 1966.
2. KNOWLES, J. :Accidental intra-arterial injection of penicillin.
Am. J. Dis. Child., 111:552, 1966.
3. DARBY, C.et al:Ischemia following an intragluteal injection
of benzathine-procaine penicillin G mixture in a one-year-old boy. Clin.
Pediatrics, 12:485, 1973.
4 . BROWN, L. & NELSON, A. :Postinfectious intravascular
thrombosis with gangrene. Arch. Surg., 94:652, 1967.
5. BORENSTINE, J. :Transverse myelitis and penicillin (Correspondence).
Am. J. Dis. Child., 112:166, 1966.
6. ATKINSON, J. :Transverse myelopathy secondary to penicillin
injection. J. Pediatrics, 75:867, 1969.
7. TALBERT, J. et al:Gangrene of the foot following intramuscular
injection in the lateral thigh:A case report with recommendations for prevention.
J. Pediatrics, 70:110, 1967.
8. FISHER, T. :Medicolegal affairs. Canad. Med. Assoc. J.
, 112:395, 1975.
9. SCHANZER, H. et al:Accidental intra-arterial injection of
penicillin G. JAMA, 242:1289, 1979.