antibioticsbooks

230 PART 5 Antiviral Drugs
The drug Kaletra (lopinavir/ritonavir) is the only
agent where the booster ritonavir is co-formulated
into the same pill.
Mechanism of Action
When the hijacked HIV-infected cell uses the cell’s
ribosomes to synthesize its own proteins, some of
them are created in long chains that need to be
cut up into their component parts to work correctly.
Protease inhibitors selectively inhibit the
viral enzyme (HIV protease) responsible for this
processing. Think of protease enzymes as a pair of
scissors that cut out prefabricated shapes from a
piece of cardboard paper—take away the scissors
(with protease inhibitors) and the shapes are just
a piece of paper.
Spectrum
Only current clinical use is for HIV. Protease
inhibitors that treat hepatitis C virus (HCV) are
different drugs and are not active against HIV, and
vice versa.
Adverse Effects
Cardiovascular: Patients with HIV living long
enough to suffer from heart attacks and strokes
was viewed (somewhat perversely) as a sign of
the success of potent antiretroviral therapy,
particularly PIs. However, the possibility of
cardiovascular adverse effects is now recognized
as a substantial problem. PIs appear to
interact with conventional cardiovascular risk
factors to increase risk for myocardial infarction
and stroke beyond that expected from just
prolonging lifespan. Atazanavir and darunavir
may confer somewhat lower risk compared