It’s not on Abbott’s web site yetbut the FDA has approved a new formulation of ritonavir — a heat-stable 100 mg tablet. From an e-mail release by the FDA:
On February 102010FDA approved Norvir (ritonavir) 100 mg Tablets. These tablets do not require refrigeration. Unlike the capsule formulation [pictured]Norvir tablets must be taken with meals. –snip–
NORVIR tablets are not bioequivalent to NORVIR capsules. Under moderate fat conditions (857 kcal; 31% fat13% protein56% carbohydrates)when a single 100 mg NORVIR dose was administered as a tablet compared with a capsuleAUC(0- ∞) met equivalence criteria but mean Cmax was increased by 26% (92.8% confidence intervals: ↑15 -↑39%).
This is obviously an advance — the Norvir soft-gel capsule is much-despised for a variety of reasonsperhaps most prominently for the glob of melted capsules that results if the medication is left in the carin a warm room in the summertimenear a radiatoretc. When Kaletra switched from capsule to tabletthe heat-stability was a big improvement in convenienceand also made treatment in resource-limited settings much easier.
Time will tell if the increase in peak levels has any effect on tolerabilitya potential concern since much of ritonavir’s toxicity is dose-related. I suspect Abbott will have both formulations available for a while until this is sorted out.
And for those who still have patients still on 600 mg twice-daily — it’s time to switch to something else!