Drug Dosing Issues and Resources

 

Appropriate dosage precautions are needed with hepatically metabolized drugs. Evaluation of medicine lists with the metabolic fate in mind can help to arrive at the optimized therapeutic dosage. All hepatically metabolized drugs should be dosed with caution, but it may be possible to cautiously use a drug metabolized by simple conjugation (morphine, for example) at a moderately reduced dose, even in severe hepatic impairment. Avoiding drugs with more complex metabolism or potential hepatotoxicity in the patient with hepatic impairment makes sense. But often we must devise ways to treat disorders with the “safer” of two options. For this reason it is important to learn and recognize the subtle differences in metabolism. In terms of dosage adjustment, also remember that if we are concerned about accumulation, the amount of an initial/individual dose may not be altered, but the adjustment may be to give this less often.