Codeine are not available without a prescription. Preparations containing pure codeine (e.g., codeine phosphate tablets or codeine phosphate linctus) are available on prescription and are considered S8 (Schedule 8, or "Controlled Drug Possession without authority illegal"). Schedule 8 preparations are subject to the strictest regulation of all medications available to consumers. In Canada tablets containing 8 mg of codeine combined with 15 mg of caffeine and 300 mg of acetaminophen are sold as T1s (Tylenol Number 1) without a prescription. A similar tablet called "A.C. & C." (which stands for Acetylsalicylic acid with Caffeine and Codeine) containing 325–375 mg of acetylsalicylic
Aminohippuric acid was given along with penicillin in order to prolong the time penicillin circulated in the blood. Because both penicillin and "para"-aminohippurate compete for the same transporter in the kidney, administering "para"-aminohippurate with penicillin decreased the clearance of penicillin from the body by the kidney, providing better antibacterial therapy. Transporters found in the kidney eliminate organic anions and cations from the blood by moving substances, in this case, drug metabolites, from blood into urine. In vultures, the NSAID diclofenac, which is extraordinarily toxic to vultures, interferes with the renal transport of uric acid via the PAH channel. p"K" = 3.83 Aminohippuric