Penicillin V

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 Oral

Onset Varies

Peak 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.