SIDE EFFECTS: Diarrhea is a common side effect of this medication. If you have diarrhea, ask your doctor or pharmacist about ways to lessen this side effect, such as using anti-diarrhea medicine. Nausea or gas may also 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). Seek immediate medical attention if any of these rare but serious side effects occur: symptoms of a heart attack (such as chest/jaw/left arm pain, shortness of breath, unusual sweating), easy bruising/bleeding, persistent nausea/vomiting, stomach/abdominal pain, dark urine, yellowing eyes/skin. This medication may rarely make your blood sugar rise, which can cause or worsen diabetes. Tell your doctor right away if you have symptoms of high blood sugar such as increased thirst/urination. If you already have diabetes, check your blood sugar regularly as directed and share the results with your doctor. Your doctor may need to adjust your diabetes medication, exercise program, or diet. Changes in body fat may occur while you are taking this medication (such as increased fat in the upper back and stomach areas, decreased fat in the arms and legs). The cause and long-term effects of these changes are unknown. Discuss the risks and benefits of treatment with your doctor, as well as the possible use of exercise to reduce this side effect. A very serious allergic reaction to this drug is rare. However, seek immediate medical attention 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 nelfinavir, 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: diabetes, heart problems (coronary artery disease, heart attack), lipid problems (high cholesterol or triglycerides/fats), hemophilia, liver problems. Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products). Children may be more sensitive to the side effects of this drug, especially diarrhea or rash. Tell your doctor if you are pregnant before using this medication. Treatment can lower the risk of passing HIV infection to your baby. Discuss the risks and benefits with your doctor. It is unknown if this medication passes into breast milk. Because breast milk can transmit HIV, do not breast-feed.

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: certain antiarrhythmics (amiodarone, quinidine), certain benzodiazepines (midazolam, triazolam), cisapride, eletriptan, eplerenone, ergot alkaloids (such as dihydroergotamine, ergonovine, ergotamine, methylergonovine), orlistat, pimozide, ranolazine, rifampin, St. John's wort, certain "statin" cholesterol drugs (lovastatin, simvastatin), certain drugs to lower acid in the stomach (proton pump inhibitors such as lansoprazole, omeprazole). Nelfinavir can slow down the removal of other medications from your body, which may affect how they work. Examples of affected drugs include alfuzosin, asunaprevir, domperidone, isavuconazonium, lurasidone, naloxegol, regorafenib, tacrolimus, drugs to treat erectile dysfunction-ED or pulmonary hypertension (such as sildenafil, vardenafil), salmeterol, suvorexant, among others. Other medications can affect the removal of nelfinavir from your body, which may affect how nelfinavir works. Examples include rifabutin, certain anti-seizure drugs (carbamazepine, phenobarbital, primidone), other HIV drugs (such as ritonavir), among others. This medication may decrease the effectiveness of hormonal birth control such as pills, patch, or ring. This could cause pregnancy. Talk to your doctor about additional or alternative reliable forms of birth control, and always use an effective barrier method (latex or polyurethane condoms/dental dams) during all sexual activity to decrease the risk of spreading HIV to others. Tell your doctor if you have any new spotting or breakthrough bleeding, because these may be signs that your hormonal birth control is not working well.

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.