Viread

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 Viread. If you are concerned about side effects, discuss the risks and benefits of Viread with your doctor.

The following side effects have been reported by at least 1% of people taking Viread. 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
• Diarrhea
• dizziness
• gas (flatulence)
• headache
• loss of appetite
• muscle pain
• muscle weakness
• nausea
• rash
• stomach pain
• 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:

• bone pain or fractures
• signs of liver problems, such as:
• dark urine
• diarrhea
• loss of appetite
• nausea
• pale stools
• vomiting
• weight loss
• yellowing of the skin or whites of the eyes
• signs of kidney problems, such as:
• increased or decreased urination
• increased thirst
• swelling of the feet or legs
• signs of infection
• Fever or chills
• severe diarrhea
• shortness of breath
• prolonged dizziness
• headache
• stiff neck
• weight loss
• listlessness

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

• Anaphylaxis (severe allergic reaction), such as:
• Hives
• shortness of breath
• swelling of the face or throat
• signs of lactic acidosis, such as:
• abdominal pain
• dizziness
• feeling cold, especially in the arms and legs
• increased breathing rate
• nausea
• rapid heart rate
• unusual tiredness
• vomiting
• signs of pancreatitis, such as:
• abdominal pain on the upper left side
• back pain
• chills
• fever
• nausea
• rapid heartbeat
• swollen abdomen

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 Viread.

Each almond-shaped, light blue, film-coated tablet, debossed with "GILEAD" and "4331" on one side and with "300" on the other side, contains 300 mg of tenofovir disoproxil fumarate, which is equivalent to 245 mg of tenofovir disoproxil. Nonmedicinal ingredients: croscarmellose sodium, lactose monohydrate, magnesium stearate, microcrystalline cellulose, and pregelatinized starch; coating: opadry II Y-30-10671-A (FD&C Blue No. 2 Aluminum Lake, hydroxypropyl methylcellulose 2910, lactose monohydrate, titanium dioxide, and triacetin).

Do not take tenofovir if you:

• are allergic to tenofovir or any ingredients of the medication
• are already taking another medication that contains tenofovir (e.g., emtricitabine - tenofovir, efavirenz - emtricitabine - tenofovir)

There may be an interaction between tenofovir and any of the following:

• acyclovir
• adefovir
• aminoglycoside antibioitics (e.g., Amikacin, gentamicin, tobramycin)
• Cobicistat
• darunavir
• Ganciclovir
• Hepatitis C antivirals (e.g., ledipasvir, sofosbuvir, velpatasvir)
• HIV protease inhibitors (e.g., atazanavir, indinavir, ritonavir, saquinavir)
• ledipasvir
• medications that affect kidney function (e.g., ACE inhibitors such as Enalapril, vancomycin, tobramycin)
• medications that are eliminated by the kidneys (e.g., penicillin, Metformin, Ranitidine, Trimethoprim)
• nonsteroidal anti-inflammatory medications (NSAIDs; e.g., Asa, Diclofenac, Indomethacin, Naproxen)
• other HIV nucleoside reverse transcriptase inhibitors (NRTIs; e.g., abacavir, didanosine, lamivudine, zidovudine)
• simeprevir
• telaprevir
• Tizanidine
• Valacyclovir
• valganciclovir

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 Viread. 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 Viread.

Bone health: Tenofovir may reduce bone mineral density and should not be taken by anyone who is at risk for bone problems. If you have Osteoporosis, discuss with your doctor how Viread may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Viread, and whether any special monitoring is needed. If you experience bone pain or a bone fracture while taking Viread, contact your doctor. Your doctor may do tests to monitor the effect of tenofovir on your bones.

Fat redistribution: Over time, Viread may change how fat is distributed in your body and may change your body shape. You may notice increased fat in the upper back and neck, breast, around the back, chest, and stomach area; or loss of fat from the legs, arms, and face. The long-term effects of this are not known.

HIV and hepatitis B co-infections: If you are taking tenofovir for hepatitis B infection and you get or have HIV infection and are not taking medication to treat HIV, tenofovir may increase the chance that your HIV infection will not respond to usual treatment. Therefore, it is important to be tested for HIV before starting treatment with tenofovir and whenever there is a risk of HIV exposure during treatment.

Immune reconstitution syndrome: When you start taking tenofovir, your immune system may get stronger and start to fight other infections that have been hidden in your body (e.g., pneumonia, herpes, or Tuberculosis). Contact your doctor if you develop any new symptoms after starting tenofovir. Report any signs of infection such as fever, chills, shortness of breath, cough, or rapid weight loss to your doctor immediately.

Kidney function: Kidney Disease or reduced kidney function may cause Viread to build up in the body, causing increased side effects. If you have kidney disease or reduced kidney function, discuss with your doctor how Viread may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Viread, and whether any special monitoring is needed. Tenofovir can cause kidney problems, including severe kidney damage and kidney failure. Your doctor may monitor your kidney function with blood tests while you are taking Viread. Additional tests may be needed if you have a history of kidney problems or if you need to take another medication that can cause kidney problems. Your doctor may also need to change the dosing schedule of Viread if you have existing kidney problems.

Lactic acidosis and enlarged liver: Viread can cause a rare but serious condition called lactic acidosis (buildup of lactic acid), together with an enlarged fatty liver. Your doctor will periodically monitor you and perform laboratory tests to check your liver function. If you notice any symptoms of this condition such as nausea, vomiting, stomach pain, weakness, tiredness, feeling cold, dizziness, lightheadedness, or irregular heartbeat, seek immediate medical attention.

Liver: Tenofovir can cause liver problems. If you have liver disease, discuss with your doctor how Viread may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Viread, and whether any special monitoring is needed. Your doctor may monitor your liver function with blood tests while you are taking tenofovir, especially if you have risk factors for liver problems. Report any signs of liver problems (e.g., nausea, vomiting, diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, pale stools) to your doctor.

Pancreatitis: Tenofovir may cause inflammation of the pancreas (pancreatitis). If you have a history of, or are at risk for developing, pancreatitis, discuss with your doctor how Viread may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Viread, and whether any special monitoring is needed. If you develop signs of pancreatitis (e.g., upper left abdominal pain, back pain, nausea, fever, chills, rapid heartbeat, swollen abdomen), contact your doctor.

Stopping the medication: When used to treat chronic hepatitis B, stopping tenofovir has been known to cause symptoms of liver inflammation to flare up and your hepatitis B infection could get worse. Take the medication exactly as prescribed by your doctor, and do not stop taking the medication without checking with your doctor first. If you and your doctor decide that you should stop taking tenofovir, you will need to have regular blood tests to check liver function and hepatitis B virus levels.

Pregnancy: Viread should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking Viread, contact your doctor immediately.

Breast-feeding: It is not known if tenofovir passes into breast milk. Women who have HIV infection are cautioned against breast-feeding because of the risk of passing HIV to a baby who does not have the infection.

Children: For the treatment of HIV infection, the safety and effectiveness of Viread have not been established for children less than 12 years old. For the treatment of chronic hepatitis B infection, the safety and effectiveness of Viread have not been established for children less than 18 years old.