A 50-year-old client is being discharged on ciprofloxacin 500 mg PO twice daily for complicated UTI. Which client teaching is most important?

Fluoroquinolones (ciprofloxacin, levofloxacin, moxifloxacin) are broad-spectrum antibiotics with significant black box warnings. Important teaching: (1) absorption is reduced by polyvalent cations — separate dose by 2 hours before or 6 hours after dairy, calcium, magnesium, iron, zinc, antacids, sucralfate, multivitamins; (2) drink plenty of water to limit crystalluria; (3) photosensitivity — use sunscreen and protective clothing, limit sun and tanning bed exposure; (4) tendon disorders including rupture (Achilles, biceps, others) — risk increases with age over 60, concurrent corticosteroids, kidney transplant; report new tendon pain, swelling, or "pop" sensation and stop the drug; avoid weight-bearing on affected limb until evaluated; (5) QT prolongation — avoid combinations with other QT-prolonging drugs and electrolyte abnormalities; (6) C. difficile colitis — report severe diarrhea or bloody stool; (7) CNS effects — confusion, agitation, hallucinations, peripheral neuropathy, mood/sleep changes, especially in elderly; (8) glucose disturbances — hypoglycemia and hyperglycemia, especially in diabetics; (9) avoid in pregnancy and children under 18 unless other options unavailable because of cartilage damage in animal studies; (10) FDA recommends not using fluoroquinolones for uncomplicated UTI, sinusitis, or bronchitis when alternatives exist because of risks. Milk/antacids, stopping when urine clears, and grapefruit juice are wrong.

Polyvalent cation separation, sunscreen, tendon and CDiff and CNS surveillance. The 2-hour-before / 6-hour-after spacing rule is the most-tested NCLEX detail.