No

Antibiotic, Macrolide

Treatment of mild to moderate upper and lower respiratory tract infections due to Moraxella catarrhalis, Streptococcus pneumoniae, Legionella pneumophila, H. influenzae, or S. pyogenes ie, acute exacerbation of chronic bronchitis, secondary bacterial infection of acute bronchitis, community-acquired pneumonia, pharyngitis/tonsillitis, and uncomplicated infections of the skin and skin structure due to Staphylococcus aureus

C

Clinical effects on the fetus: Animal studies indicate the use of dirithromycin during pregnancy should be avoided if possible

Breast-feeding/lactation: Use caution when administering to nursing women

Hypersensitivity to any macrolide or component of dirithromycin; use with pimozide

Contrary to potential serious consequences with other macrolides (eg, cardiac arrhythmias), the combination of terfenadine and dirithromycin has not shown alteration of terfenadine metabolism; however, caution should be taken during coadministration of dirithromycin and terfenadine; pseudomembranous colitis has been reported and should be considered in patients presenting with diarrhea subsequent to therapy with dirithromycin

1% to 10%:

Central nervous system: Headache, dizziness, vertigo, insomnia

Dermatologic: Rash, pruritus, urticaria

Endocrine & metabolic: Hyperkalemia

Gastrointestinal: Abdominal pain, nausea, diarrhea, vomiting, dyspepsia, flatulence

Hematologic: Thrombocytosis, eosinophilia, segmented neutrophils

Neuromuscular & skeletal: Weakness, pain, increased CPK

Respiratory: Increased cough, dyspnea

<1%: Palpitations, vasodilation, syncope, edema, anxiety, depression, somnolence, fever, malaise, dysmenorrhea, hypochloremia, hypophosphatemia, increased uric acid, dehydration, abnormal stools, anorexia, gastritis, constipation, abnormal taste, xerostomia, abdominal pain, mouth ulceration, polyuria, vaginitis, neutropenia, thrombocytopenia, decreased hemoglobin/hematocrit; increased alkaline phosphatase, bands, basophils; leukocytosis, monocytosis, Increased ALT/AST, GGT; hyperbilirubinemia, paresthesia, tremor, myalgia, amblyopia, tinnitus, increased creatinine, phosphorus, epistaxis, hemoptysis, hyperventilation, hypoalbuminemia, flu-like syndrome, diaphoresis, thirst

Symptoms of overdose include nausea, vomiting, abdominal pain, diarrhea

Treatment is supportive; dialysis has not been found effective

CYP3A3/4 enzyme inhibitor

Increased toxicity: Avoid use with pimozide (due to risk of significant cardiotoxicity) and triazolam

Note: Interactions with nonsedating antihistamines (eg, terfenadine, astemizole), cisapride, and theophylline are not known to occur, however, caution is advised with coadministration.

After being converted during intestinal absorption to its active form, erythromycylamine, dirithromycin inhibits protein synthesis by binding to the 50S ribosomal subunits of susceptible microorganisms

Absorption: Rapidly absorbed and nonenzymatically hydrolyzed to erythromycylamine; T_max: 4 hours

Distribution: V_d: 800 L; rapidly and widely distributed (higher levels in tissues than plasma)

Protein binding: 14% to 30%

Metabolism: Hydrolyzed to erythromycylamine

Bioavailability: 10%

Half-life: 8 hours (range: 2-36 hours)

Elimination: Via bile (81% to 97% of dose)

Adults: Oral: 500 mg once daily for 5-14 days (14 days required for treatment of community-acquired pneumonia due to Legionella, Mycoplasma, or S. pneumoniae; 10 days is recommended for treatment of S. pyogenes pharyngitis/tonsillitis)

Dosing adjustment in hepatic impairment: None needed in mild dysfunction; not studied in moderate to severe dysfunction

Administer with food or within 1 hour of eating

Temperature, CBC

May cause insomnia; rarely may cause anxiety, drowsiness, or depression; macrolides have been reported to cause nightmares, confusion, and mood lability

Contraindicated with pimozide; may cause neutropenia; use caution with clozapine and carbamazepine; may increase carbamazepine and triazolam levels

No information available to require special precautions

No effects or complications reported

Take with food or after meals around-the-clock. Do not chew, cut, or crush tablets. Take complete prescription even if you are feeling better. You may experience dizziness or drowsiness (use caution when driving or engaging in tasks that require alertness until response to drug is known); nausea or vomiting (small frequent meals, frequent mouth care, sucking lozenges, or chewing gum may help); constipation (increased exercise, dietary fiber, fruit, or fluid may help); or diarrhea (buttermilk, boiled milk, or yogurt may help). Report skin rash or itching, easy bruising or bleeding, unhealed sores of mouth, itching or vaginal discharge, fever or chills, unusual cough, muscle cramping or weakness, or palpitations or chest pain. Pregnancy/breast-feeding precautions: Inform prescriber if you are or intend to be pregnant. Consult prescriber if breast-feeding.

Do not crush tablets

Tablet, enteric coated: 250 mg

"Dirithromycin," Med Lett Drugs Ther, 1995, 37(962):109-10.

McConnell SA and Amsden GW, "Review and Comparison of Advanced-Generation Macrolides Clarithromycin and Dirithromycin," Pharmacotherapy, 1999, 19(4):404-15.

Niederman MS, Bass JB Jr, Campbell GD, et al, "Guidelines for the Initial Management of Adults With Community-Acquired Pneumonia: Diagnosis, Assessment of Severity, and Initial Antimicrobial Therapy," Am Rev Respir Dis, 1993, 148(5):1418-26.

"Pimozide (Orap) Contraindicated With Clarithromycin (Biaxin) and Other Macrolide Antibiotics," FDA Medical Bulletin, October 1996, 3.

Sharma R and Cramer M, "Focus on Dirithromycin: A New Once Daily Macrolide Antibiotic," Formulary, 1995, 30:769-83.

Tartaglione TA, "Therapeutic Options for the Management and Prevention of Mycobacterium avium Complex Infection in Patients With the Acquired Immunodeficiency Syndrome," Pharmacotherapy, 1996, 16(2):171-82.

Wintermeyer SM, Abdel-Rahman SM, and Nahata MC, "Dirithromycin: A New Macrolide," Ann Pharmacother, 1996, 30(10):1141-9.