Brand Name(s):

  • Fosrenol®

WHY is this medicine prescribed?

Lanthanum is used to reduce blood levels of phosphate in patients with kidney disease. High levels of phosphate in the blood can cause bone problems. Lanthanum is in a class of medications called phosphate binders. It works by preventing absorption of phosphate from food in the stomach.

HOW should this medicine be used?

Lanthanum comes as a chewable tablet to take by mouth. It is usually taken with or immediately after food several times a day as directed by your doctor. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take lanthanum exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Chew the tablets completely before swallowing; do not swallow the tablets whole. If you have trouble chewing the tablets you may crush them before chewing.

Your doctor will probably start you on a low dose of lanthanum and gradually increase your dose, not more often than once every 2 to 3 weeks.

Are there OTHER USES for this medicine?

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

What SPECIAL PRECAUTIONS should I follow?

Before taking lanthanum,

  • tell your doctor and pharmacist if you are allergic to lanthanum, any other medications, or any of the ingredients in lanthanum chewable tablets. Ask your pharmacist for a list of the ingredients.
  • tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: ampicillin, calcium channel blockers such as amlodipine (Norvasc), diltiazem (Cardizem, Dilacor, Tiazac, others), felodipine (Plendil), isradipine (Dynacirc), nicardipine (Cardene), nifedipine (Adalat, Procardia), nimodipine (Nimotop), nisoldipine (Sular), and verapamil (Calan, Covera, Isoptin, Verelan); cholesterol-lowering medications (statins) such as atorvastatin (Lipitor) and rosuvastatin (Crestor); fluoroquinolone antibiotics such as ciprofloxacin (Cipro), gemifloxacin (Factive), levofloxacin (Levaquin), moxifloxacin (Avelox), norfloxacin (Noroxin), or ofloxacin (Floxin); iron salts; medications for the treatment of malaria; tetracycline antibiotics such as demeclocycline (Declomycin), doxycycline (Doryx, Vibramycin), minocycline (Dynacin, Minocin), and tetracycline (Sumycin); or thyroid medications such as levothyroxine (Synthroid. Levothroid). These medications may interact with lanthanum if they are taken at the same time or within a few hours before or after lanthanum is taken, so your doctor or pharmacist will probably tell you to allow a number of hours between doses of any of these medications and doses of lanthanum. Your doctor may also need to change the doses of your medications or monitor you more carefully for side effects. Many other medications may interact with lanthanum, so be sure to tell your doctor and pharmacist about all the medications you are taking, even if they do not appear on this list.
  • tell your doctor if you have paralytic ileus (condition in which digested food does not move through the intestines), or any condition where the bowels are blocked, including fecal impaction (a large amount of dry, hard stool stuck in the rectum). Your doctor will probably tell you not to take lanthanum.
  • tell your doctor if you have or have ever had an ulcer, ulcerative colitis (condition that causes swelling, redness, and sores in the lining of the intestines), Crohn's disease (condition in which the body attacks the lining of the intestines causing pain, diarrhea, weight loss, and fever), colon cancer, or diabetes, or if you have ongoing constipation. Also tell your doctor if you ever had any kind of surgery on your stomach or intestines.
  • tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking lanthanum, call your doctor.

What SPECIAL DIETARY instructions should I follow?

Your doctor may instruct you to follow a low-phosphorus diet. Follow these directions carefully.

What should I do IF I FORGET to take a dose?

Take the missed dose with food as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

What SIDE EFFECTS can this medicine cause?

Lanthanum may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • nausea
  • vomiting
  • abdominal (stomach area) pain
  • diarrhea
  • constipation

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately:

  • severe abdominal pain or cramping
  • bloating
  • pain and swelling of the abdomen
  • inability to pass gas or have a bowel movement

Lanthanum may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online [at Web Site] or by phone [1-800-332-1088].

What should I know about STORAGE and DISPOSAL of this medication?

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.

What should I do in case of OVERDOSE?

In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.

Symptoms of overdose may include the following:

  • headache
  • nausea
  • vomiting

What OTHER INFORMATION should I know?

Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your body's response to lanthanum.

Before having any x-rays of your abdominal area, tell your doctor and the x-ray technicians that you are taking lanthanum.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

AHFS® Consumer Medication Information. © Copyright, The American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.

Selected Revisions: September 15, 2011.