penicillin V (penicillin V potassium)

penicillin V (penicillin V potassium)

(pen i sill' in)

Novo-Pen VK (CAN), 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 eight 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 eight 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 eight doses.
> 60 lb: 2 g PO 30 min–1 hr before the procedure, then 500 mg q 6 hr for eight 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 eight 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 two or four divided doses.

PEDIATRIC PATIENTS < 9 YR

·        Anthrax prophylaxis: 50 mg/kg/day PO in four divided doses.

Pharmacokinetics

Route	Onset	Peak
Oral	Varies	60 min

Metabolism: Hepatic; T_1/2: 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, LFTs, 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 otherpenicillins.

Teaching points

·        Avoid self-treating other infections with this antibiotic because it is specific for the infection being treated. Complete the full course of drug therapy.

·        You may experience these side effects: 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.