SIDE EFFECTS: Dizziness, diarrhea, headache, or trouble sleeping may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly. Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects. As your immune system gets stronger, it can begin to fight off infections you already had, possibly causing disease symptoms to come back. You could also have symptoms if your immune system becomes overactive. This reaction may happen at any time (soon after starting HIV treatment or many months later). Get medical help right away if you have any serious symptoms, including: unexplained weight loss, severe tiredness, muscle aches/weakness that doesn't go away, headaches that are severe or don't go away, joint pain, numbness/tingling of the hands/feet/arms/legs, vision changes, signs of infection (such as fever, chills, swollen lymph nodes, trouble breathing, cough, non-healing skin sores), signs of an overactive thyroid (such as irritability, nervousness, heat intolerance, fast/pounding/irregular heartbeat, bulging eyes, unusual growth in the neck/thyroid known as a goiter), signs of a certain nerve problem known as Guillain-Barre syndrome (such as trouble breathing/swallowing/moving your eyes, drooping face, paralysis, trouble speaking). Tell your doctor right away if any of these unlikely but serious side effects occur: mental/mood changes (such as depression, anxiety, confusion). Tell your doctor right away if any of these rare but serious side effects occur: signs of kidney problems (such as a change in the amount of urine), unusual thirst. Rarely, this medication can cause severe (sometimes fatal) liver and blood problems (lactic acidosis). Tell your doctor right away if you develop symptoms of liver problems (such as nausea/vomiting that doesn't stop, loss of appetite, stomach/abdominal pain, yellowing eyes/skin, dark urine) or lactic acidosis (such as deep/rapid breathing, drowsiness, nausea/vomiting, unusual weakness). Tenofovir may increase the risk of bone loss. Discuss the risks and benefits of treatment with your doctor, as well as the possible use of calcium and vitamin D to reduce this side effect. If you are at risk for bone loss, your doctor may monitor your bone mineral density. Tell your doctor right away if any of the following serious side effects occur: bone pain, easily broken bones. Tenofovir can commonly cause a rash that is usually not serious. However, you may not be able to tell it apart from a rare rash that could be a sign of a severe reaction. Therefore, seek immediate medical attention if you develop any rash. A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing. This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist. In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch. In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

PRECAUTIONS: Before taking tenofovir, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details. Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney problems, liver problems (such as hepatitis C, cirrhosis), bone problems (such as bone disease, bone loss/osteoporosis, weak/broken bones), disease of the pancreas (pancreatitis), alcohol use. This drug may make you dizzy. Alcohol or marijuana can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana. Also limit alcohol because it may increase your risk of liver problems and pancreatitis. Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products). During pregnancy, this medication should be used only when clearly needed. Treatment can lower the risk of passing HIV infection to your baby, and tenofovir may be part of that treatment. Discuss the risks and benefits with your doctor. This medication passes into breast milk. Consult your doctor before breast-feeding. If you have HIV infection, do not breast-feed because breast milk can transmit HIV.

DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval. Some products that may interact with this drug include: adefovir, orlistat, other drugs that may harm the kidneys (including aminoglycosides such as amikacin/gentamicin). Do not take this medication with other products that contain tenofovir. Some other drugs to treat HIV infection (including atazanavir) may also interact with tenofovir. Tenofovir can decrease the effectiveness of atazanavir (by decreasing blood levels). If you are taking atazanavir with this product, you may need to also take another medication (ritonavir). Consult your doctor or pharmacist for more details. Your doctor will adjust your medications and monitor your treatment to reduce the risk of side effects.

OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.