A nurse is reviewing the medication administration record of a client who has benign prostatic hyperplasia (BPH). The client asks the nurse about taking saw palmetto. The nurse should instruct the client that which of the following medications interacts adversely with saw palmetto?

Rationale: A. Zolpidem: Zolpidem is a sedative-hypnotic used for insomnia and does not have known interactions with saw palmetto. It primarily affects the central nervous system and does not influence platelet activity or coagulation pathways. B. Ipratropium: Ipratropium is an anticholinergic bronchodilator used for respiratory conditions such as COPD and asthma. It does not interact with saw palmetto, as the herb mainly affects hormonal and coagulation pathways rather than respiratory medications. C. Clopidogrel: Saw palmetto can potentiate the effects of antiplatelet and anticoagulant medications like clopidogrel, increasing the risk of bleeding. The herb exhibits mild antiplatelet activity, which can lead to additive effects and potential hemorrhagic complications when combined with platelet inhibitors. D. Penicillin: Penicillin is an antibiotic with no pharmacologic interaction with saw palmetto. The herb does not interfere with antibacterial mechanisms or alter antibiotic metabolism, making concurrent use safe from an interaction standpoint.