<p><strong>Drugs Binding to Antacids</strong>: There is a potential for Lanthanum Carbonate to interact with compounds which bind to cationic antacids (i.e., aluminum-,magnesium-, or calcium-based); therefore, do not administer such compounds within 2 hours of dosing with Lanthanum Carbonate.<br />
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<strong>Quinolone Antibiotic</strong>s: Co-administration of Lanthanum Carbonate with quinolone antibiotics may reduce the extent of their absorption. The bioavailability of oral ciprofloxacin was decreased by approximately 50% when taken with Lanthanum Carbonate in a single-dose study in healthy volunteers. Administer oral quinolone antibiotics at least 1 hour before or 4 hours after Lanthanum Carbonate. When oral quinolones are given for short courses, consider eliminating the doses of Lanthanum Carbonate that would normally be scheduled near the time of quinolone intake to improve quinolone absorption.<br />
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<strong>Levothyroxine</strong>: the bioavailability of levothyroxine was decreased by approximately 40% when taken together with Lanthanum Carbonate. Administer thyroid hormone replacement therapy at least 2 hours before or 2 hours after dosing with Lanthanum Carbonate and monitor thyroid stimulating hormone (TSH).</p>