Hepatic impairment can alter the pharmacokinetic profiles of
cardiovascular drugs, which can lead to unwanted toxicity. In the presence of
cirrhosis, portosystemic shunting occurs and
cytochrome P450 activity is reduced. Impaired
oxygen uptake caused by changes in the liver's sinusoids, as proposed by the
oxygen limitation theory, may also explain the alteration of
drug metabolism seen in
cirrhosis. With
congestive heart failure, sinusoidal congestion and hypoperfusion of the liver are seen. Similar to
cirrhosis, the common pathway for hepatic damage in
congestive heart failure seems to be liver
hypoxia, which may explain the disease's effect on
drug metabolism. Since routine hepatic function tests do not always relate to the liver's ability to eliminate drugs, existing guidelines for dosing
cardiovascular drugs in patients with hepatic impairment are limited. This article provides guidance for dosing
cardiovascular drugs in cirrhotic and
heart failure patients based on available research data. Altered
drug metabolism, especially in
congestive heart failure, tends to be overlooked or not realized in clinical practice. Therefore, further research is needed in
congestive heart failure to better elucidate safe prescribing patterns.