- The patient is unwilling or unable to avoid 10 days before and 3 days after the protocol scheduled liver biopsies the use of medications or herbal supplements that are potentially hepatotoxic (eg, 3-hydroxy-3-methyl glutaryl coenzyme A reductase inhibitors, erythromycin, valproic acid, anti-depressants, kava, echinacea) and/or may cause or prolong bleeding (eg, anti-coagulants, ibuprofen, aspirin, garlic supplements, ginkgo, ginseng).