275 - We have prepared a Patient Tear Off Sheet for Product X which provides information on the indication, dosing/administration, side effects, talk to your doctor immediately if you have x,y and z and interactions with drugs. My question is with respect to "Product X may interact with drugs to treat: Chest pain, angina (e.g. amyl nitrate "poppers") HIV infections (e.g. indinavir or itraconazole) Fungal infections...

  • continued ... (e.g. ketoconazole or itraconazole) Infections (e.g. gatifloxacin) Irregular heartbeat (e.g. amiodarone, sotalol, quinidine, procainamide) Prostate problems or high blood pressue (e.g. alpha-blockers).

    I would like to propose a change to Infections (in the list above) to replace "e.g. gatifloxacin" with "e.g. erythromycin and chlarithromycin" because these latter 2 drugs are contraindicated with use with product X (and are missing from the list)...and because gatifloxacin 400 mg is no longer available in Canada. There is a 0.3% gatifloxicin eye-drop solution available in Canada but it has no clinical bearing on the drug-drug interactions that were investigated with Product X. Note that the 0.3% gatifloxacin eye drop solution is not mentioned in the current approved Label for Product X. Only the 400 mg gatifloxacin is mentioned in Part 1/2 of the Product Monograph under Warnings/Precations, Drug-Interactions and Detailed Pharmacology.

    Health Canada did not inform us of the removal of 400 mg gatifloxacin product...and we have only just stumbled upon gatifloxacin in Section 3 of the PM (which states: Drugs that may interact with Product X include - gatifloxacin (used to treat infections). We propose to revise this statement in the product label with Health Canada. If this tear off sheet is intended to provide relevant patient information, would it be OK to replace "gatifloxacin" with "erythromycin and chlarithromycin". Or does "gatifloxacin" need to remain in this list...and "erythromycin and clarithromycin" be added too. Looking forward to your response. Thank you.

    Response: There is generally no need to disclose risks relating to concomitant use with particular products which have been completely withdrawn from the Canadian market. BUT the fact that the specific agent, gatifloxacin, is presented as an example denotes that the risk extends to other drugs used to treat infections. It is therefore clear that the risk relating to concomitant use with drugs used to treat infections must still be conveyed in some manner (albeit not necessarily by including "gatifloxacin" as the example). Assessment of the complete monograph typically reveals signals indicating which agents could be used as examples in place of the withdrawn product. It is possible that your proposed plan is workable, but this could only be confirmed after assessment of the complete product monograph in the context of the therapeutic area (and the corresponding current medical practice).