Which Diltiazem? June 2006

There are 4 different formulations of diltiazem and 9 different products Plain SR CD LA

Plain Tablets – Dilzem® Release diltiazem immediately Usually administered THREE or FOUR times daily (only lasts ~ 8 hrs) Must NOT be substituted for slow release preparations 30mg tablet 60mg tablet

Sustained Release Capsules – Dilzem SR® Gelatin capsule filled with coated beads SR = sustained release but not for 24 hours! Release diltiazem slowly over 12 to 16 hours Usually administered TWICE daily SR 90mg capsule SR 120mg capsule

Controlled Delivery Capsules – Cardizem CD® Gelatin capsule filled with coated beads of differing thickness Release diltiazem slowly over 24 hours Usually administered ONCE daily CD 120mg capsule CD 180mg capsule CD 240mg capsule

Long Acting Tablets – Dilzem LA® Inner core of diltiazem surrounded by a porous membrane Release diltiazem slowly over 24 hours Usually administered ONCE daily LA 180mg tablet LA 240mg tablet

Diltiazem Release Characteristics PreparationPeak concentrationDuration of action Plain 30mg, 60mg tablets (Dilzem) 2-4 hours ~ 8 hours SR 90mg, 120mg (Dilzem SR) 2-8 hours ~ 12 to 16 hours CD 120mg, 180mg, 240mg (Cardizem CD) hours (based on CD 360mg dose) ~ 24 hours LA 180mg, 240mg (Dilzem LA) 2-8 hours ~ 24 hours

Case Patient received one dose of ordinary release diltiazem 60mg Ward round, dose increased to 240mg daily No formulation specified on drug chart “Nurse instructed to “make up dose” Patient received 60mg x 3 as one dose Patient transferred to ICU

Summary Slow release preparations – SR, CD, LA: – are not interchangeable - SR is a BD formulation – must not be crushed Plain, ordinary release tablets must not be used to make up the difference Specify the formulation/brand name –Eg Cardizem CD, Dilzem LA When changing formulation/brand consider the timing of the next dose