In the U.S.—

In Canada—

Another commonly used name is EHDP.

• Antihypercalcemic
• Bone resorption inhibitor

Etidronate ( eh-tih-DROE-nate) is used to treat Paget's disease of bone. It may also be used to treat or prevent a certain type of bone problem that may occur after hip replacement surgery or spinal injury.

Etidronate is also used to treat hypercalcemia (too much calcium in the blood) that may occur with some types of cancer.

This medicine is available only with your doctor's prescription, in the following dosage forms:

Oral
• Tablets (U.S. and Canada)

Parenteral
• Injection (U.S.)

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For etidronate, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to etidronate. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Diet—Make certain your health care professional knows if your diet includes large amounts of calcium, such as milk or other dairy products, or if you are on any special diet, such as a low-sodium or low-sugar diet. Calcium in the diet may prevent the absorption of oral etidronate.

Pregnancy—Studies have not been done in humans. However, studies in rats injected with large doses of etidronate have shown that etidronate causes deformed bones in the fetus.

Breast-feeding—It is not known if etidronate passes into breast milk. However, this medicine has not been reported to cause problems in nursing babies.

Children—Some changes in bone growth may occur in children, but will usually go away when the medicine is stopped.

Older adults—When etidronate is given by injection along with a large amount of fluids, older people tend to retain (keep) the excess fluid.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking etidronate, it is especially important that your health care professional know if you are taking any of the following:

• Antacids containing calcium, magnesium, or aluminum or
• Mineral supplements or other medicines containing calcium, iron, magnesium, or aluminum—These medicines may decrease the effects of etidronate, and should be taken at least 2 hours before or after taking etidronate

• Bone fracture, especially of arm or leg—Etidronate may increase the risk of bone fractures

• Intestinal or bowel disease—Etidronate may increase the risk of diarrhea

• Kidney disease—High blood levels of etidronate may result causing serious side effects

Take etidronate with water on an empty stomach at least 2 hours before or after food (midmorning is best) or at bedtime. Food may decrease the amount of etidronate absorbed by your body.

Take etidronate only as directed. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered. To do so may increase the chance of side effects.

In some patients, etidronate takes up to 3 months to work. If you feel that the medicine is not working, do not stop taking it on your own. Instead, check with your doctor.

It is important that you eat a well-balanced diet with an adequate amount of calcium and vitamin D (found in milk or other dairy products). Too much or too little of either may increase the chance of side effects while you are taking etidronate. Your doctor can help you choose the meal plan that is best for you. However, do not take any food, especially milk, milk formulas, or other dairy products, or antacids, mineral supplements, or other medicines that are high in calcium or iron (high amounts of these minerals may also be in some vitamin preparations), magnesium, or aluminum within 2 hours of taking etidronate. To do so may keep this medicine from working properly.

Dosing—

The dose of etidronate will be different for different patients. Follow your doctor's order or the directions on the label. The following information includes only the average doses of etidronate. If your dose is different, do not change it unless your doctor tells you to do so.

• For oral dosage form (tablets):
  • For treating Paget's disease of bone:
    • Adults—Dose is based on body weight and must be determined by your doctor. The dose to start is 5 milligrams (mg) per kilogram (kg) (2.3 mg per pound) of body weight a day, usually as a single dose, for not more than six months. Some people may need 6 to 10 mg per kg (2.7 to 4.6 mg per pound) of body weight a day for not more than six months. Others may need 11 to 20 mg per kg (5 to 9.1 mg per pound) of body weight a day for not more than three months. Your doctor may change your dose depending on your response to treatment.
    • Children—Dose must be determined by your doctor.
  • For treating or preventing a certain type of bone problem that may occur after hip replacement:
    • Adults—Dose is based on body weight and must be determined by your doctor. The usual dose is 20 mg per kg (9.1 mg per pound) of body weight a day for one month before surgery, and for three months after surgery.
    • Children—Dose must be determined by your doctor.
  • For treating or preventing a certain type of bone problem that may occur after spinal injury:
    • Adults—Dose is based on body weight and must be determined by your doctor. The usual dose is 20 mg per kg (9.1 mg per pound) of body weight a day for two weeks, beginning as soon as possible after your injury. Your doctor may then decrease your dose to 10 mg per kg (4.5 mg per pound) of body weight for an additional ten weeks.
    • Children—Dose must be determined by your doctor.
  • For treating hypercalcemia (too much calcium in the blood):
    • Adults—Dose is based on body weight and must be determined by your doctor. The usual dose is 20 mg per kg (9.1 mg per pound) of body weight a day for thirty days. Treatment usually does not continue beyond ninety days.
    • Children—Dose must be determined by your doctor.
• For injection dosage form:
  • For treating hypercalcemia (too much calcium in the blood):
    • Adults—Dose is based on body weight and must be determined by your doctor. The usual dose is 7.5 mg per kg (3.4 mg per pound) of body weight, injected slowly into your vein over 2 hours. This dose is repeated for two more days. Your doctor may repeat the treatment after at least seven days.
    • Children—Dose must be determined by your doctor.

Missed dose—

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage—

To store this medicine:

• Keep out of the reach of children.
• Store away from heat and direct light.
• Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
• Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

It is important that your doctor check your progress at regular visits even if you are between treatments and are not taking this medicine. If your condition has improved and your doctor has told you to stop taking etidronate, your progress must still be checked. The results of laboratory tests or the occurrence of certain symptoms will tell your doctor if more medicine must be taken. Your doctor may want you to begin another course of treatment after you have been off the medicine for at least 3 months.

If this medicine causes you to have nausea or diarrhea and it continues, check with your doctor. The dose may need to be changed.

If bone pain occurs or worsens during treatment, check with your doctor.

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• More common
  • Bone pain or tenderness (increased, continuing, or returning—in patients with Paget's disease) 
  
  

• Less common
  • Bone fractures, especially of the thigh bone 
  
  

• Rare
  • Hives;  skin rash or itching;  swelling of the arms, legs, face, lips, tongue, and/or throat  
  
  

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

• More common--at higher doses
  • Diarrhea;  nausea 
  
  

• Less common--with injection
  • Loss of taste or metallic or altered taste 
  
  

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.