Terfenadine Category

But terfenadine and astemizole are both potentially cardio-toxic, and drug interactions are an important concern. Can we manage the potential risks in our system? Both drugs are available without prescription. Therefore it depends mostly on the patient and pharmacist to deal with potential interactions. But the drugs of concern are not just erythromycin and ketocona-zole. […]

Decreased clearance of terfenadine by inhibitors of CYP3A4 explains raised serum concentrations. But if ter-fenadine is normally completely metabolized, how does it work when taken orally? The answer is as an active metabolite. Terfenadine is really a pro-drug. It is not terfenadine that is doing the job – it is metabolized to the real antihistamine: […]

Of these, it was drug interactions that focused attention on terfenadine. In the United States over a seven-year period, the FDA received reports of 25 cases of ventricular arrhythmias in patients who had taken terfenadine. Eleven of these patients were also taking drugs that inhibit drug metabolism, such as imidazoles or macrolide antibiotics. The cytochrome […]

Terfenadine (Seldane; Hoechst Marion Roussel) and astemizole (Hismanal; McNeil Consumer Products) were introduced in Canada approximately 17 years ago as the first nonsedating antihistamines. This was a noteworthy event because the use and safety of antihistamine therapy was often limited by unwanted sedation. It is now clear that both terfenadine and astemizole are associated with […]