Erythromycin biliary excretion

Drugs that interfere with biliary excretion of glucuronidation (erythromycin, rifampin, cholestyramine) might decrease entacapone elimination. 

The macrolides are orally absorbed but they are acid-labile. They therefore need to be administered in acid-resistant capsules or as acid-resistant esters. The macrolides are widely distributed into all fluids except the CNS. Protein binding is about 90%. They are eliminated via biliary excretion with extensive enterohepatic circulation. Elimination half-lives vary from 1.4 h for erythromycin to 40-60 h for azithromycin. 

Chelvan P, Hamilton-Miller JMT, Brumfitt W. Biliary excretion of erythromycin after parenteral administration. Br J Clin Pharmacol 1979 8 233-235. 

IS% of the 14-hydroxy metabolite is excreted in the urine. Biliary excretion of clarithromycin is much lower than that of erythromycin. Clarithromycin is widely distributed into the tissues, which retain much higher concentrations than the plasma. Protein-binding fractions in the plasma range from 65 to 70%. The plasma half-life of clarithromycin is 4.3 hours. 

Eliminated primarily by metabolism and biliary excretion follow package insert for dose adjustments Drug interaction with phenytoin decreases phenytoin levels drug interaction with erythromycin (may inhibit vinorelbine metabolism) increased risk of vinorelbine toxicity... 

Erythromycin (estolate is best absorbed oral form)—wide distribution into tissue and is eliminated mainly via biliary excretion. 

Answer B. Erythromycin is eliminated largely via biliary excretion, and decreases in renal function do not usually require a dosage reduction unless creatinine clearance <10 mL/min, All of the other antimicrobial drugs listed are eliminated by the kidney, at rates proportional to creatinine clearance, so major dose reductions would be needed in patients with renal dysfunction to avoid toxicity. 

It has been postulated that only those compounds which are readily excreted in bile are inhibitory of the BSP and bilirubin excretory mechanisms (H4). Both antibiotics have high biliary excretion rates (B65) and both are concentrated to a considerable degree in bile. Erythromycin, another antibiotic with high biliary excretion (B55) has been implicated in a transient cholestasis (PIO). It would be of interest therefore to test the effect of other antibiotics which have high biliary excretion rates, e.g., penicillin. 

AnsB Erythromycin is eliminated largely via biliary excretion, and... 

Antimicrobial drugs that are eliminated via hepatic metabolism or biliary excretion include erythromycin, cefoperazone, clindamycin, doxycycline, isoniazid, ketoconazole, and nafcillin. The answer is (C). 

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