<p>Orally administered erythromycin is readily absorbed. Food intake does not appear to exert effects on serum concentrations of erythromycin.<sup class="text-reference-group"><a class="reference-popover-link" data-content="FDA Approved Drug Products: Ery-Ped (erythromycin ethylsuccinate) granules for oral suspension" href="#reference-L7261">21</a></sup> Some interindividual variation exists in terms of erythromycin absorption, which may impact absorption to varying degrees.<sup class="text-reference-group"><a class="reference-popover-link" data-content="FDA Approved Drug Products: Ery-Ped (erythromycin ethylsuccinate) granules for oral suspension" href="#reference-L7261">21</a></sup> The Cmax of erythromycin is 1.8 mcg/L<sup class="text-reference-group"><a class="reference-popover-link" data-content="Wang LQ, Hu ZY, Yu Q, Guo X, Xiong J, Huang ZZ, Cheng ZN: [Pharmacokinetics of erythromycin stinoprate capsule]. Zhong Nan Da Xue Xue Bao Yi Xue Ban. 2005 Apr;30(2):197-201. (PubMed ID 15898434)" href="#reference-A180598">15</a></sup> and the Tmax is 1.2 hours.<sup class="text-reference-group"><a class="reference-popover-link" data-content="Kavi J, Webberley JM, Andrews JM, Wise R: A comparison of the pharmacokinetics and tissue penetration of spiramycin and erythromycin. J Antimicrob Chemother. 1988 Jul;22 Suppl B:105-10. doi: 10.1093/jac/22.supplement_b.105. (PubMed ID 3182434)" href="#reference-A180607">19</a></sup> The serum AUC of erythromycin after the administration of a 500mg oral dose was 7.3±3.9 mg.h/l in one pharmacokinetic study.<sup class="text-reference-group"><a class="reference-popover-link" data-content="Kavi J, Webberley JM, Andrews JM, Wise R: A comparison of the pharmacokinetics and tissue penetration of spiramycin and erythromycin. J Antimicrob Chemother. 1988 Jul;22 Suppl B:105-10. doi: 10.1093/jac/22.supplement_b.105. (PubMed ID 3182434)" href="#reference-A180607">19</a></sup> Erythromycin is well known for a bioavailability that is variable (18-45%) <sup class="text-reference-group"><a class="reference-popover-link" data-content="Amsden GW: Erythromycin, clarithromycin, and azithromycin: are the differences real? Clin Ther. 1996 Jan-Feb;18(1):56-72; discussion 55. (PubMed ID 8851453)" href="#reference-A174451">6</a>,<a class="reference-popover-link" data-content="Mather LE, Austin KL, Philpot CR, McDonald PJ: Absorption and bioavailability of oral erythromycin. Br J Clin Pharmacol. 1981 Aug;12(2):131-40. doi: 10.1111/j.1365-2125.1981.tb01191.x. (PubMed ID 7306427)" href="#reference-A180595">14</a></sup> after oral administration and its susceptibility to broken down under acidic conditions.<sup class="text-reference-group"><a class="reference-popover-link" data-content="Krasniqi S, Matzneller P, Kinzig M, Sorgel F, Huttner S, Lackner E, Muller M, Zeitlinger M: Blood, tissue, and intracellular concentrations of erythromycin and its metabolite anhydroerythromycin during and after therapy. Antimicrob Agents Chemother. 2012 Feb;56(2):1059-64. doi: 10.1128/AAC.05490-11. Epub 2011 Nov 14. (PubMed ID 22083477)" href="#reference-A174448">5</a></sup></p>