A nurse is caring for an elderly patient who has been taking diphenhydramine (Benadryl) for insomnia. Which central nervous system effect is the nurse most likely to observe in this patient?

A. "If the medicine causes an upset stomach, take an antacid at the same time.": Ciprofloxacin should not be taken with antacids containing magnesium or aluminum because these reduce the medication’s absorption and effectiveness.

B. "Limit your daily fluid intake while taking this medication.": Clients should be encouraged to increase, not limit, fluid intake when taking ciprofloxacin. Adequate hydration helps prevent crystalluria and protects renal function.

C. "This medication will affect your eyesight, wear sunglasses while outside.": Ciprofloxacin does not typically cause vision changes or photosensitivity requiring sunglasses. It is not a significant or common side effect of quinolones.

D. "You should report any discomfort in your tendons while taking this medication.": Ciprofloxacin carries a risk for tendinitis and tendon rupture, especially in older adults and those taking corticosteroids. Reporting tendon pain early allows the healthcare provider to discontinue the drug and prevent permanent tendon damage.

A. A candida fungal infection.: Candida infections are treated with antifungal medications such as fluconazole or nystatin, not acyclovir. Acyclovir is ineffective against fungi because it specifically targets viral DNA synthesis.

B. An MRSA bacterial infection.: Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterial infection treated with antibiotics such as vancomycin or linezolid. Acyclovir has no antibacterial properties and would not be effective for MRSA.

C. A herpes viral infection.: Acyclovir is an antiviral drug primarily used to treat infections caused by the herpes simplex virus (HSV-1 and HSV-2) and varicella-zoster virus. It works by inhibiting viral DNA replication, helping reduce symptom severity and frequency of outbreaks.

D. A giardia protozoal infection.: Giardia infections are caused by protozoa and are typically treated with antiprotozoal medications such as metronidazole. Acyclovir has no activity against protozoa and would not treat this type of infection.