Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes Actonel DR (Risedronate-delayed-release). If you are concerned about side effects, discuss the risks and benefits of Actonel DR (Risedronate-delayed-release) with your doctor.

The following side effects have been reported by at least 1% of people taking Actonel DR (Risedronate-delayed-release). Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• abdominal pain
• Constipation
• Diarrhea
• headache
• heartburn or acid reflux
• joint, bone, or muscle pain
• nausea
• sore throat, or nose
• vomiting

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

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

• delayed healing and infection of mouth and jaw (usually after tooth extraction)
• difficulty swallowing
• eye pain, redness, or swelling
• mouth sores painful teeth, mouth or jaw
• new or unusual pain in the hip, groin, or thigh
• sensitivity of eyes to light
• severe pain in bones, muscles, or joints
• signs of damage to the esophagus (e.g., pain in the esophagus [throat area] or behind the breastbone, chest pain, difficulty swallowing, pain when swallowing, or new or worsening heartburn)
• signs of low levels of calcium in the blood (e.g., numbness, tingling, or muscle spasms)
• vision changes

Stop taking the medication and seek immediate medical attention if any of the following occur:

• symptoms of a Anaphylaxis (severe allergic reaction) (e.g., Hives; difficulty breathing; swelling of the face, mouth, tongue, or throat)
• symptoms of a stomach or intestinal ulcer (e.g., nausea, vomiting, abdominal pain, loss of weight or appetite, black or bloody stools, or vomiting blood)
• symptoms of thigh bone fracture (e.g., severe and sharp leg pain)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking Actonel DR (Risedronate-delayed-release).

Each delayed-release, oval-shaped, yellow tablet with "EC 35" engraved on one side contains risedronate 35 mg. Nonmedicinal ingredients: edetate disodium, ferric oxide yellow, magnesium stearate, methacrylic acid copolymer dispersion, silicified microcrystalline cellulose, polysorbate 80, simethicone, sodium starch glycolate, stearic acid, talc, and triethyl citrate.

Do not take Actonel DR (Risedronate-delayed-release) if you:

• are allergic to risedronate or any ingredients of Actonel DR (Risedronate-delayed-release)
• have hypocalcemia (low blood calcium levels)

There may be an interaction between risedronate delayed-release and any of the following:

• aminoglycoside antibiotics (e.g., Amikacin, gentamicin, tobramycin)
• antacids (e.g., aluminum hydroxide, calcium carbonate, magnesium hydroxide)
• calcium supplements
• Deferasirox
• H2 antagonists (e.g., Famotidine, Ranitidine)
• iron-containing products
• magnesium-containing supplements or laxatives
• nonsteroidal anti-inflammatory drugs (NSAIDs; e.g., Ibuprofen, Naproxen, Ketoprofen)
• proton pump inhibitors (PPIs; e.g., Esomeprazole, Omeprazole, Pantoprazole)
• systemic angiogenesis inhibitors (e.g., Axitinib, Bevacizumab, Lenalidomide, Pazopanib, Regorafenib, Vandetanib)

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with Actonel DR (Risedronate-delayed-release). Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the Nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or Allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use Actonel DR (Risedronate-delayed-release).

Effects on the esophagus and stomach: Risedronate delayed-release may irritate the lining of the esophagus (the tube that connects the mouth and the stomach) and the stomach.

Esophagitis (inflammation of the esophagus lining), ulcers, and erosions have been reported by people who take risedronate delayed-release. To ease the passage of the medication to the stomach, and thus reduce the risk of irritation of the esophagus, swallow risedronate delayed-release with at least 120 mL (4 ounces) of plain water with breakfast. Do not lie down for at least 30 minutes after taking the tablet.

If you experience problems swallowing, find it painful to swallow, develop pain behind the sternum (breastbone), or have new or worsening heartburn, stop taking Actonel DR (Risedronate-delayed-release) and contact your doctor.

Jaw problems: Some people taking this type of medication have developed a type of jaw problem called osteonecrosis of the jaw. This is more likely to occur if you have dental surgery, have cancer, are receiving chemotherapy or corticosteroids (e.g., Prednisone), or already have dental health problems. It is important to practice good mouth care during treatment with Actonel DR (Risedronate-delayed-release). Talk to your doctor to find out whether you might be at risk. Your doctor may ask you to see your dentist before you start Actonel DR (Risedronate-delayed-release). Dental work should be done before you start treatment with Actonel DR (Risedronate-delayed-release) and if possible dental procedures should be avoided during treatment.

If you experience any mouth sores, pain, swelling, or infection of the mouth or jaw, especially after having a tooth removed, contact your doctor immediately.

Kidney function: Risedronate may not be removed from the body at the expected rate if the kidneys are not working properly. This increases the risk of side effects for the person taking Actonel DR (Risedronate-delayed-release). If you have reduced kidney function or Kidney Disease, discuss with your doctor how Actonel DR (Risedronate-delayed-release) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Actonel DR (Risedronate-delayed-release), and whether any special monitoring is needed.

If you have severely reduced kidney function, you should not take risedronate delayed-release.

Low calcium levels or vitamin D deficiency: Risedronate delayed-release may lower the calcium levels in your blood. If you have low blood calcium before you start taking Actonel DR (Risedronate-delayed-release), it may get worse during treatment. Your low blood calcium must be treated before you take Actonel DR (Risedronate-delayed-release). Most people with low blood calcium levels do not have symptoms, but some people may have symptoms.

Call your doctor right away if you have symptoms of low blood calcium such as spasms, twitches, or cramps in your muscles; or numbness or tingling in your fingers, toes, or around your mouth.

Your doctor may prescribe or suggest that you take calcium and vitamin D to help prevent low calcium levels in your blood, while you take risedronate delayed-release.

Musculoskeletal pain: Severe bone, muscle, and joint pain have been reported by some people taking Actonel DR (Risedronate-delayed-release). If you experience any severe symptoms, talk to your doctor about whether you should continue taking Actonel DR (Risedronate-delayed-release).

Other risedronate products: Do not take Actonel DR (Risedronate-delayed-release) if you are already taking a medication than contains risedronate.

Thigh bone fractures: Some people have developed fractures with little or no trauma in their thigh bone while taking this or similar medications. Symptoms of a fracture may include new or unusual pain in your hip, groin, or thigh. Call your doctor immediately if you have these symptoms.

Vision issues: Some people have developed inflammation of the eye after taking this or similar medication. If you develop any issues with your eye or vision, call your doctor immediately.

Pregnancy: Risedronate delayed-release is not intended to be taken by pregnant women and has not been studied for use by pregnant women.

Breast-feeding: Risedronate delayed-release is not intended to be taken by breast-feeding women. It is not known if risedronate passes into breast milk.

Children: The safety and effectiveness of Actonel DR (Risedronate-delayed-release) have not been established for children.