Pharmacokinetics erythromycin

Harris, R. Z., Tsunoda, S. M., Mroczkowski, R, Wong, H., and Benet, L. Z. (1996) The effects of menopause and hormone replacement therapies on prednisolone and erythromycin pharmacokinetics. Clin. Pharmacol. Then 59,429-435. 

Brannan MD, Reidenberg P, Radwanski E, Shneyer L, Lin CC, Cayen MN, Affrime MB. Loratadine administered concomitantly with erythromycin pharmacokinetic and electrocardiographic evaluations. Clin Pharmacol Ther 1995 58(3) 269-78. 

Kinoshita, T., Son, D.-S., Shimoda, M. Kokue, E. (1995) Impact of age-related alteration of plasma i-acid glycoprotein concentration on erythromycin pharmacokinetics in pigs. American Journal of Veterinary Research, 56, 362-365. 

Cimetidine, erythromycin, and dextropropoxyphene had no effect on the pharmacokinetics of MHD. Results with warfarin show no evidence of interaction with either single or repeated doses of oxcarbazepine. 

The macrolide antibacterials (including erythromycin, clarithromycin and telithromycin) are often implicated in interactions, most frequently as a result of inhibition of the CYP3A4 enzyme system in the liver and enterocytes. Erythromycin inhibits the metabolism of carbamazepine, ciclosporin and theophylline significant increases in serum levels and features of toxicity have been documented. Careful clinical and pharmacokinetic monitoring are required in a patient taking any of these drugs who requires concomitant erythromycin. 

Clozapine is metabolized by hepatic CYP 1A2 and, to a lesser degree, CYP 3A3/4 therefore, the drug is subject to changes in serum concentration when combined with medications that inhibit or induce these enzymes. Serum clozapine levels increase with coadministration of fluvoxamine or erythromycin and decrease with coadministration of phenobarbital or phenytoin and with cigarette smoking (Byerly and DeVane 1996). These pharmacokinetic interactions are particularly important because of the dose-dependent risk of seizures. 

Damkier P, Hansen LL, Brosen K. Effect of diclofenac, disulfiram, itraconazole, grapefruit juice and erythromycin on the pharmacokinetics of quinidine. Br J Clin Pharmacol 1999 48(6) 829-838. 

Kanazawa S, Ohkubo T, Sugawara K. The effects of grapefruit juice on the pharmacokinetics of erythromycin. Eur J Clin Pharmacol 2001 56(11) 799-803. 

Pharmacokinetics attd Pharmacology. Older macrolides such as erythromycin exhibit relatively low serum concentrations, short in vivo half-hves, highly variable oral absorption, and low oral bioavailability. Improvements in these pharmacokinetic parameters have been accomplished for newer derivatives. The principal side effects of macrolides aie gastrointestinal problems, such as pain, indigestion, diarrhea, nausea, and vomiting. 

Dey, S., Gunda, S., Mitra, A. K. Pharmacokinetics of Erythromycin in Rabbit Corneas after Single-Dose Infusion Role of P-Glycoprotein as a Barrier to in Vivo Ocular Drug Absorption. J. Pharmacol. Exptl. Then 2004, 311, 246-256. 

By use of these basic concepts, Wu et al. [87] conducted an examination of the pharmacokinetics of cyclosporine after administration in the presence of two known CYP3A inhibitors, ketaconazole and erythromycin and the CYP3A inducer rifampin. Alterations to the cyclosporin hepatic extraction ratio were measured in the presence of the inducer/inhibitor, and oral cyclosporin biovailability (relative to IV administration in the presence/absence of the interacting species) was calculated. These data are reproduced in Table 3 and provide several impor-... 

Tran JQ, Di Cicco RA, Sheth SB, et al. Assessment of the potential pharmacokinetic and pharmacodynamic interaction between erythromycin and argatroban. J Clin Pharmacol 1999 39 513-519. 

Honig PK, Woosley RL, Zamani K, et al. Changes in the pharmacokinetics and electrocardiographic pharmacodynamics of terfenadine with concomitant administration of erythromycin. Clin Pharmacol Ther 1992 52 231-238. 

Phillips J, Antal E, Smith R. A pharmacokinetic drug interaction between erythromycin and triazolam. J Clin Psychopharmacol 1986 6 297-299. 

Cheng CL, Smith DE, Carver PL, et al. Steady-state pharmacokinetics of dela-virdine in HIV-positive patients effect on erythromycin breath test. Clin Pharmacol Ther 1997 61 531-543. 

Triazolam plasma concentrations were determined by gas chromatography with electron capture detection (73,95). The pharmacokinetic results demonstrated that mean clearance during Trials B and C were nearly identical (413 and 416 mL/min, respectively) that is, coadministration of azithromycin had no effect on the pharmacokinetics of triazolam (Fig. 5). However, triazolam clearance was significantly reduced to 146 mL/min by erythromycin (Trial D) and to 95 mL/min by clarithromycin (Trial E). Thus, the in vivo kinetic results are highly consistent with the in vitro data. 

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