A-Z Drug Facts > Penicillin V (Phenoxymethyl Penicillin, Penicillin V Potassium)

Penicillin V

( Phenoxymethyl Penicillin , Penicillin V Potassium ) Pronouncation: (pen-ih-SILL-in V)
Class: Natural penicillin

Trade Names:
Beepen-VK
- Tablets 250 mg
- Tablets 500 mg
- Powder for oral solution 125 mg/5 mL
- Powder for oral solution 250 mg/5 mL

Trade Names:
Pen-Vee K
- Tablets 250 mg
- Tablets 500 mg
- Powder for oral solution 125 mg/5 mL
- Powder for oral solution 250 mg/5 mL

Trade Names:
Penicillin VK
- Tablets 250 mg
- Tablets 500 mg
- Powder for oral solution 125 mg/5 mL
- Powder for oral solution 250 mg/5 mL

Trade Names:
Veetids
- Tablets 250 mg
- Tablets 500 mg
- Powder for oral solution 125 mg/5 mL

Trade Names:
Veetids ‘250’
- Powder for oral solution 250 mg/5 mL

APO-Pen VK (Canada)
Nadopen-V (Canada)
Novo-Pen-VK (Canada)
Nu-Pen-VK (Canada)
Pen-Vee (Canada)
PVF K (Canada)

Pharmacology

Inhibits mucopeptide synthesis of bacterial cell wall.

Pharmacokinetics

Absorption

Oral absorption is 60% to 73%. T _max is 0.5 to 1 h. C _max is 2 to 3 mcg/mL.

Distribution

Widely distributed to most tissues and body fluids; distribution into CSF is low with noninflamed meninges. Protein binding is 80%. Vd is 0.5 L/kg. Crosses the placenta and distributes into breast milk.

Metabolism

Hepatic biotransformation is 55%.

Elimination

Mainly renal (20% to 40% as unchanged). T _½ is 0.5 to 1 h.

Special Populations

Renal Function Impairment

For CrCl less than 10 mL/min, t _½ increased to 4.1 h.

Indications and Usage

Treatment of upper respiratory tract infections; treatment of pneumococcal, streptococci, and staphylococcal infections and fusospirochetosis (Vincent infection) of oropharynx caused by susceptible microorganisms.

Unlabeled Uses

Prophylactic treatment of sickle cell anemia in children; treatment of anaerobic infections; treatment of Lyme disease ( Borrelia burgdorferi ).

Contraindications

Hypersensitivity to penicillins. Do not treat severe pneumonia, empyema, bacteremia, pericarditis, meningitis, and purulent or septic arthritis with oral penicillin V during acute stage.

Dosage and Administration

Adults and children older than 12 yr of age

PO 125 to 500 mg 4 times daily.

General Advice

Administer without regard to meals. Administer with food if GI upset occurs.

Storage/Stability

Reconstituted oral solution is stable for 14 days when refrigerated (36° to 46°F)

Drug Interactions

Beta-blockers

May potentiate anaphylactic reactions of penicillin.

Contraceptives, oral

May reduce efficacy of oral contraceptives.

Erythromycin

May cause synergism or antagonism to develop.

Tetracyclines

May impair bactericidal effects of penicillin V.

Laboratory Test Interactions

Antiglobulin (Coombs') test

Drug may cause false-positive results.

Urine glucose test

Drug may cause false-positive results with copper sulfate tests (Benedict's test, Fehling's test or Clinitest tablets); enzyme-based tests (eg, Clinistix , Tes-tape ) are not affected.

Urine protein determinations

Drug may cause false-positive reactions with sulfosalicylic acid and boiling test, acetic acid test, biuret reaction and nitric acid test; bromphenol blue test ( Multi-Stix ) is not affected.

Adverse Reactions

CNS

Dizziness; fatigue; insomnia; reversible hyperactivity; neurotoxicity (eg, lethargy, neuromuscular irritability, hallucinations, convulsions, seizures).

EENT

Itchy eyes; furry tongue; black “hairy” tongue; stomatitis; sore mouth or tongue.

GI

Glossitis; gastritis; dry mouth; nausea; vomiting; abdominal pain or cramp; epigastric distress; diarrhea or bloody diarrhea; rectal bleeding; flatulence; enterocolitis; pseudomembranous colitis.

Genitourinary

Interstitial nephritis (eg, oliguria, proteinuria, hematuria, hyaline casts, pyuria); nephropathy; increased BUN and creatinine.

Hematologic

Decreased hemoglobin, hematocrit, RBC, WBC, neutrophils, lymphocytes, platelets; increased lymphocytes, monocytes, basophils, eosinophils, and platelets.

Metabolic

Elevated serum alkaline phosphatase; hypernatremia; hypokalemia; albumin, total proteins and uric acid.

Miscellaneous

Hypersensitivity reactions (eg, urticaria, angioneurotic edema, laryngospasm, laryngeal edema, bronchospasm, hypotension, vascular collapse, death, maculopapular to exfoliative dermatitis, vesicular eruptions, erythema multiforme, serum sickness, skin rashes, prostration); vaginitis; hyperthermia.

Precautions

Pregnancy

Category B .

Lactation

Small amount excreted in breast milk. May cause diarrhea, candidiasis, or allergic response in breast-feeding infant.

Hypersensitivity

Reactions range from mild to life threatening. Administer drug with caution to cephalosporin-sensitive patients because of possible crossreactivity.

Renal Function

Use drug with caution; dosage adjustment may be necessary.

Superinfection

May result in bacterial or fungal overgrowth of nonsusceptible organisms.

Pseudomembranous colitis

May occur because of overgrowth of clostridia.

Streptococcal infections

Therapy must be minimum of 10 days.

Overdosage

Symptoms

Neuromuscular hyperexcitability, agitation, confusion, asterixis, hallucinations, stupor, coma, multifocal myoclonus, encephalopathy, hyperkalemia.

Patient Information

• Instruct patient to complete entire course of therapy even if feeling better.
• Advise patient to use calibrated measuring device for liquid preparation.
• Instruct penicillin allergic patient to carry medical identification (eg, card, bracelet).
• Advise patient to use nonhormonal form of contraceptive during penicillin V therapy.
• Inform patient of the signs of hypersensitivity (eg, skin rash, itching, hives, shortness of breath, wheezing) and other adverse reactions, such as black tongue, sore throat, nausea, vomiting, severe diarrhea, fever, swollen joints. Instruct patient to notify health care provider if these symptoms occur.
• Instruct patient to notify health care provider if there is no improvement in symptoms of infection.
• Instruct patient to notify health care provider of signs of superinfection (eg, vaginitis, black “hairy” tongue).