Medications and Drugs
Pharmacy Author: Omudhome Ogbru, PharmD
Medical and Pharmacy Editor: Jay W. Marks, MD
GENERIC NAME: penicillin V
BRAND NAME: Veetids (Pen-Vee-K is no longer available in the U.S.)
DRUG CLASS AND MECHANISM: Penicillin V is an oral form of the antibiotic,
penicillin, that is used to treat bacterial infections. In 1928, Alexander
Fleming noted that mold belonging to the genus Penicillium inhibited the growth
of bacteria. Fleming called this unknown antibacterial substance penicillin. Ten
years later, a group at Oxford University began to investigate penicillin in
laboratory mice. Penicillin was hailed as a miracle drug and saved countless
lives in World War II.
Today, many derivatives of penicillin have been developed
which inhibit more types of bacteria than the original, life-saving drug.
Penicillin stops bacteria from multiplying by preventing bacteria from forming
the walls that surround them. The walls are necessary to protect bacteria from
their environment and to keep the contents of the bacterial cell together.
Bacteria cannot survive without a cell wall. Penicillin is most effective when
bacteria are actively multiplying and forming cell walls. Penicillin itself is
active against Streptococci (including Streptococcus pneumoniae),
Listeria,
Neisseria gonorrhoeae, Clostridium, Peptococcus, and Peptostreptococcus. Most
staphylococci now are resistant to penicillin.
PRESCRIPTION: Yes
GENERIC AVAILABLE: Yes
PREPARATIONS: Tablets: 250, 500mg. Powder: 125, 250 mg/5 mL.
STORAGE: Tablets should be kept between 15 C (59 F) and 30 C (86 F). The
solution should be kept refrigerated and can be used for up to 14 days after it
is reconstituted by the pharmacist. It must be shaken before each use and should
be kept well-sealed.
PRESCRIBED FOR: Penicillin V is effective for treatment of laryngitis,
bronchitis, pneumonia, and soft tissue and skin infections caused by susceptible
bacteria. It also is used for preventing recurrence of
rheumatic fever and
chorea (a disorder of uncontrolled movement of the body). Only mild to moderate
infections are treated with oral penicillin V. Patients with more severe
infections are given penicillin by injection.
DOSING: The usual adult dose of penicillin V is 125 to 500 mg every 6-8
hours.
DRUG INTERACTIONS: Probenecid (Benemid) causes an increase in the level of
penicillin in the blood by reducing the elimination of penicillin by the
kidneys. In fact, sometimes probenecid is combined with penicillin so that a
smaller amount of penicillin results in higher blood levels.
PREGNANCY: Penicillin is considered safe during
pregnancy.
NURSING MOTHERS: Penicillin is excreted in breast milk and may cause diarrhea
or allergic responses in nursing infants. If penicillin is used while nursing,
the potential benefit of penicillin for the mother should be weighed against the
potential risk of side effects in the infant.
SIDE EFFECTS: Common side effects of penicillin V include nausea,
vomiting,
diarrhea, abdominal pain, rash, and itching. Patients with a history of allergic
reactions to other penicillins should not receive penicillin V. Persons who are
allergic to the cephalosporin class of antibiotics, which are related to the
penicillins, for example, cefaclor (Ceclor), cephalexin (Keflex), and cefprozil
(Cefzil), may or may not be allergic to penicillins. Serious but rare reactions
include seizures, severe allergic reactions (anaphylaxis), and low platelet or
red blood cell count. Penicillins can alter the normal bacteria in the colon and
encourage overgrowth of some bacteria such as
Clostridium difficile which causes
inflammation of the colon (pseudomembranous colitis). Patients who develop signs
of pseudomembranous colitis after starting penicillin (diarrhea, fever,
abdominal pain, and possibly shock) should contact their physician immediately.
Reference: FDA Prescribing Information
Last Editorial Review: 3/27/2009
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
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