Zithromax is available in 2 dosages that is azithromycin 250 mg and azithromycin 500 mg. It also contains dibasic calcium phosphate anhydrous, pregelatinized starch, sodium croscarmellose, magnesium stearate, sodium lauryl sulfate, and an aqueous film coat consisting ofhypromellose, titanium dioxide, lactose, and triacetin. Fact Table Formula C38H72N2O12 License EU EMA, US FDA Bioavailability 38% for 250 mg capsules Legal status RX Only Chemical Name Azithromycin Elimination half-life 11–14 hour (single dose), 68 hours (multiple dosing) Dosage (Strength) 250mg (30 tablets), 500mg (30 tablets) Pregnancy Consult a doctor Brands Zithromax, Zithromax Tri-Pak, Zithromax Z-Pak, Zmax Protein binding 90% PubChem CID 55185 MedlinePlus a697037 ChEBI 2955 ATC code J01FA10 DrugBank DB00207 KEGG D07486 Routes of administration By mouth