penicillin V (penicillin V potassium)
(pen i sill' in)
Nadopen-V (CAN), Novo-Pen VK (CAN), Pen-VK, Veetids
Pregnancy Category B
Drug classes
Antibiotic
Penicillin (acid stable)
Therapeutic actions
Bactericidal: Inhibits cell wall synthesis of sensitive organisms, causing cell death.
Indications
• Mild to moderately severe infections caused by sensitive organisms—
streptococci, pneumococci, staphylococci, fusospirochetes
• Prophylaxis against bacterial endocarditis in patients with valvular heart disease
undergoing dental or upper respiratory tract surgery
• Unlabeled uses: Prophylactic treatment of children with sickle cell anemia, mild
to moderate anaerobic infections, Lyme disease, post-exposure anthrax
prophylaxis
Contraindications and cautions
• Contraindicated with allergies to penicillins, cephalosporins, or other allergens.
• Use cautiously with renal disorders, pregnancy, lactation (may cause diarrhea or
candidiasis in the infant).
Available forms
Tablets—250, 500 mg; powder for oral solution—125, 250 mg/5 mL
Dosages
ADULTS AND PATIENTS > 12 YR
• Fusospirochetal infections: 250–500 mg q 6–8 hr PO.
• Streptococcal infections (including otitis media, URIs of mild to moderate
severity, scarlet fever, erysipelas): 125–250 mg q 6–8 hr PO for 10 days. Or,
500 mg q 12 hr for 10 days.
• Pneumococcal infections: 250–500 mg q 6 hr PO until afebrile for 48 hr.
• Staphylococcal infections of skin and soft tissues: 250–500 mg q 6–8 hr PO.
• Prophylaxis against bacterial endocarditis, dental or upper respiratory
procedures: 2 g PO 30 min–1 hr before the procedure, then 500 mg q 6 hr for 8
doses.
• Alternate prophylaxis: 1 million units penicillin G IM mixed with 600,000 units
procaine penicillin G 30 min–1 hr before the procedure, then 500 mg penicillin V
PO q 6 hr for 8-hr doses.
• Lyme disease: 500 mg PO qid for 10–20 days.
• Mild, uncomplicated cutaneous anthrax: 200–500 mg PO qid.
ADULTS AND PATIENTS > 9 YR
• Anthrax prophylaxis: 7.5 mg/kg PO qid.
PEDIATRIC PATIENTS < 12 YR
15–62.5 mg/kg/day PO given q 6–8 hr. Calculate doses according to weight.
• Prophylaxis against bacterial endocarditis, dental or upper respiratory
procedures:
< 60 lb: 1 g PO 30 min–1 hr before the procedure, then 250 mg q 6 hr for 8 doses.
> 60 lb: 2 g PO 30 min–1 hr before the procedure, then 500 mg q 6 hr for 8 doses.
• Alternate prophylaxis: < 30 kg: 30,000 units penicillin G/kg IM mixed with
600,000 units procaine penicillin G 30 min–1 hr before the procedure and then
250 mg penicillin V PO q 6 hr for 8 doses.
• Sickle cell anemia as prophylaxis of S. pneumoniae septicemia: 125 mg PO bid.
• Mild, uncomplicated cutaneous anthrax in children > 2 yr: 25–50 mg/kg daily in
2 or 4 divided doses.
PEDIATRIC PATIENTS < 9 YR
• Anthrax prophylaxis: 50 mg/kg/day PO in 4 divided doses.
Pharmacokinetics
Route Onset Peak
Oral Varies 60 min
Metabolism: Hepatic; T1/2: 30 min
Distribution: Crosses placenta; enters breast milk
Excretion: Urine
Adverse effects
• CNS: Lethargy, hallucinations, seizures
• GI: Glossitis, stomatitis, gastritis, sore mouth, furry tongue, black "hairy" tongue,
nausea, vomiting, diarrhea, abdominal pain, bloody diarrhea, enterocolitis,
pseudomembranous colitis, nonspecific hepatitis
• GU: Nephritis—oliguria, proteinuria, hematuria, casts, azotemia, pyuria
• Hematologic: Anemia, thrombocytopenia, leukopenia, neutropenia, prolonged
bleeding time
• Hypersensitivity reactions: Rash, fever, wheezing, anaphylaxis (sometimes
fatal)
• Other: Superinfections, sodium overload leading to CHF; potassium poisoning—
hyperreflexia, coma, cardiac arrhythmias, cardiac arrest (potassium
preparations)
Interactions
Drug-drug
• Decreased effectiveness with tetracyclines
Nursing considerations
Assessment
• History: Allergies to penicillins, cephalosporins, or other allergens; renal
disorders; pregnancy; lactation
• Physical: Culture infection; skin color, lesions; R, adventitious sounds; bowel
sounds: CBC, liver and renal function tests, serum electrolytes, Hct, urinalysis
Interventions
• Culture infection before beginning treatment; reculture if response is not as
expected.
• Continue therapy for at least 2 days after infection has disappeared, usually 7–10
days.
• Do not administer oral drug with milk, fruit juices, or soft drinks; a full glass of
water is preferred; this oral penicillin is less affected by food than other
penicillins.
Teaching points
• Avoid self-treating other infections with this antibiotic because it is specific for
the infection being treated.
• These side effects may occur: Nausea, vomiting, diarrhea, mouth sores.
• Report difficulty breathing, rashes, severe diarrhea, mouth sores, unusual bleeding
or bruising.
Adverse effects in Italic are most common; those in Bold are life-threatening.
