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Why is this medication prescribed?

Lanthanum is used to reduce blood levels of phosphate in people with kidney disease. High levels of phosphate in the blood can cause bone problems. Lanthanum is in a clsas of medications called phosphate binders. It binds phosphorus that you get from foods in your diet and prevents it from being absorbed into your blood stream.

How should this medicine be used?

Lanthanum comes as a chewable tablet and as an oral powder 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.

Sprinkle the oral powder on a small amount of applesauce or a similar food and take the mixture immediately, along with your meal. Do not store the prepared mixture for future use after mixing. Do not open the oral powder container until you are ready to use the medication. Do not mix lanthanum oral powder with a liquid.

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.

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 or oral powder. 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. Your doctor may tell you to take your medications at certain times before or after you take lanthanum, change the doses of your medications, or monitor you more carefully for side effects. Be sure to mention any of the following: calcium channel blockers such as amlodipine (Norvasc), diltiazem (Cardizem, Cartia, Diltzac, others), felodipine, isradipine, nicardipine (Cardene), nifedipine (Adalat, Afeditab, Procardia), nimodipine (Nymalize), nisoldipine (Sular), or verapamil (Calan, Covera, Verelan, in Tarka). If you are taking an angiotensin-converting enzyme (ACE) inhibitor such as benazepril (Lotensin, in Lotrel), captopril, enalapril (Epaned, Vasotec), fosinopril, lisinopril (Qbrelis, Prinivil, in Zestoretic), moexipril, or perindopril (Aceon, in Prestalia); ampicillin; a tetracycline antibiotic such as demeclocycline, doxycycline (Doryx, Monodox, Oracea, others), minocycline (Dynacin, Minocin), or tetracycline (Achromycin V, in Pylera); a cholesterol-lowering medication (statins) such as atorvastatin (Lipitor) or rosuvastatin (Crestor); a medication for the treatment of malaria; or a thyroid medication such as levothyroxine (Levo-T, Synthroid, Tirosint, others), you should take it at least 2 hours before or 2 hours after you have taken lanthanum. Take fluoroquinolone antibiotics such as ciprofloxacin (Cipro), gemifloxacin (Factive), levofloxacin (Levaquin), or moxifloxacin (Avelox, Moxeza) at least 1 hour before or 4 hours after taking lanthanum. 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 (a condition which causes swelling and sores in the lining of the colon [large intestine] and rectum), peritonitis (inflammation of the lining of the stomach), Crohn’s disease (a condition in which the body attacks the lining of the intestines causing pain, diarrhea, weight loss, and fever), stomach or colon cancer, diabetes, gastroparesis (slowed movement of food from the stomach to the small intestine), or if you have gastrointestinal problems such as 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 breastfeeding. 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. Talk to your doctor about foods that contain high amounts of phosphorus.

What should I do if I forget a 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 medication 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 ( 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).

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA’s Safe Disposal of Medicines website ( for more information if you do not have access to a take-back program.

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach.

In case of emergency/overdose

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at If the victim has collapsed, had a seizure, has trouble breathing, or can’t be awakened, immediately call 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.

Brand names

  • Fosrenol®
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