Etidronate is used to treat Paget's disease of bone (a condition in which the bones are soft and weak and may be deformed, painful, or easily broken) and to prevent and treat heterotopic ossification (growth of bone tissue in an area of the body other than the skeleton) in people who have had total hip replacement surgery (surgery to replace the hip joint with an artificial joint) or in people who have had an injury to the spinal cord. Etidronate is in a class of medications called bisphosphonates. It works by slowing the breakdown of old bone and the formation of new bone.

Etidronate comes as a tablet to take by mouth. It is usually taken once a day on an empty stomach. Treatment for Paget's disease may be repeated if symptoms come back or worsen after some time has passed. Take etidronate at around the same time(s) every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take etidronate exactly as directed. Do not take more or less of it or take it more often or for a longer period of time than prescribed by your doctor.

Etidronate may not work properly and may damage the esophagus (tube that connects the mouth and stomach) or cause sores in the mouth if it is not taken according to the following instructions. Tell your doctor if you do not understand, you do not think you will remember, or you are unable to follow these instructions:

• Swallow the tablets with a full glass (6 to 8 ounces [180 to 240 mL]) of plain water while you are sitting or standing.
• Sit or stand upright after taking etidronate.
• Do not eat, drink, or take any other medications (including vitamins or antacids) for 2 hours before and 2 hours after you take etidronate.

If you are taking etidronate to treat Paget's disease of bone or to prevent or treat heterotopic ossification, it may take some time for your condition to improve. Do not stop taking etidronate without talking to your doctor.

Before taking etidronate,

• tell your doctor and pharmacist if you are allergic to etidronate, any other medications, or any of the ingredients in etidronate 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: angiogenesis inhibitors such as bevacizumab (Avastin), everolimus (Afinitor, Zortress), pazopanib (Votrient), sorafenib (Nexavar), or sunitinib (Sutent); anticoagulants ('blood thinners') such as warfarin (Coumadin, Jantoven); cancer chemotherapy; and oral steroids such as dexamethasone, methylprednisolone (Medrol), and prednisone (Rayos). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
• if you are taking vitamin and mineral supplements such as iron, or if you are taking antacids containing calcium, magnesium, or aluminum (Maalox, Mylanta, Tums, others), take them 2 hours before or 2 hours after you take etidronate.
• tell your doctor if you have or have ever had problems with your esophagus such as an esophageal stricture (narrowing of the esophagus that causes swallowing difficulties) or achalasia (disorder which affects the ability of the esophagus to move food toward the stomach), or osteomalacia (softening of bones due to a lack of minerals). Your doctor may tell you not to take etidronate.
• tell your doctor if you are unable to sit or stand upright and if you have or have ever had anemia (condition in which the red blood cells do not bring enough oxygen to all the parts of the body); a low level of calcium in your blood; difficulty swallowing, heartburn, ulcers, or other stomach problems; cancer; enterocolitis (swelling in the intestines); any type of infection, especially in your mouth; problems with your mouth, teeth, or gums; any condition that stops your blood from clotting normally; or kidney disease. Your doctor may need to change the dose of your medications or monitor you carefully for side effects.
• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. Also tell your doctor if you plan to become pregnant at any time in the future because etidronate may remain in your body for years after you stop taking it. Call your doctor if you become pregnant during or after your treatment with etidronate.
• you should know that etidronate may cause osteonecrosis of the jaw (ONJ, a serious condition of the jaw bone), especially if you have dental surgery or treatment while you are taking the medication. A dentist should examine your teeth and perform any needed treatments, including cleaning or fixing ill-fitted dentures, before you start to take etidronate. Be sure to brush your teeth and clean your mouth properly while you are taking etidronate. Talk to your doctor before having any dental treatments while you are taking this medication.
• you should know that etidronate may cause severe bone, muscle, or joint pain. You may begin to feel this pain within days, months, or years after you first take etidronate. Although this type of pain may begin after you have taken etidronate for some time, it is important for you and your doctor to realize that it may be caused by etidronate. Call your doctor right away if you experience severe pain at any time during your treatment with etidronate. Your doctor may tell you to stop taking etidronate and your pain may go away after you stop taking the medication.

If you have not already eaten, take the missed dose as soon as you remember it. If you have already eaten, take the missed dose 2 hours after you last ate. 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.

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. 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:

• vomiting
• stomach cramps
• diarrhea
• pain, burning, numbness, or tingling in the hands or feet
• muscle spasms and cramps

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 (http://goo.gl/c4Rm4p) 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. http://www.upandaway.org

It is important that you get enough calcium and vitamin D and eat a balanced diet while you are taking etidronate. Your doctor will tell you which foods are good sources of these nutrients and how many servings you need each day. If you find it difficult to eat enough of these foods, tell your doctor. In that case, your doctor may prescribe or recommend a supplement.

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

• nausea
• diarrhea

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

• new or worsening heartburn
• pain when swallowing
• chest pain
• swelling of the face, throat, tongue, lips, eyes, hands, feet, ankles, or lower legs
• hoarseness
• difficulty swallowing
• blisters on the skin

Etidronate 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 (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

Etidronate is also used sometimes to treat and prevent osteoporosis (condition in which the bones become thin and weak and may break easily) caused by corticosteroids (a type of medication that may cause osteoporosis). Talk to your doctor about the possible risks of using this medication for your condition.

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

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

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.