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

The following side effects have been reported by at least 1% of people taking Prezista. 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
• changes in cholesterol levels
• Diarrhea
• headache
• increased fat in the upper back and around the back, neck, breast, chest, and stomach area (or loss of fat from the legs, arms, and face)
• nausea
• trouble sleeping
• vomiting
• weakness

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:

• increased bleeding for people who have Hemophilia
• signs of bleeding (e.g., unusual nosebleeds, bruising, blood in urine, coughing blood, bleeding gums, cuts that don't stop bleeding)
• skin rash
• symptoms of Diabetes (e.g., excessive thirst, urination, or eating; unexplained weight loss; poor wound healing; or infections)
• symptoms of liver problems (e.g., abdominal pain, persistent vomiting, feeling unwell, Fever, itching, yellowing of the skin and eyes, dark urine)

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

• signs of a serious allergic reaction (e.g., swelling of face, throat, or tongue; Hives; or difficulty breathing)
• signs of a severe skin reaction (e.g., blistering, peeling, a rash covering a large area of the body, a rash that spreads quickly, or a rash combined with fever or discomfort)
• symptoms of pancreatitis (e.g., abdominal pain, nausea, vomiting)

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 Prezista.

75 mg
Each white, caplet-shaped, film-coated tablet, debossed with "75" on one side and "TMC" on the other side, contains 75 mg of darunavir (corresponding to darunavir ethanolate 81.31). Nonmedicinal ingredients: colloidal silicon dioxide, crospovidone, magnesium stearate, and microcrystalline cellulose; film coating: polyethylene glycol, polyvinyl alcohol - partially hydrolyzed, talc, and titanium dioxide.

150 mg
Each white, oval-shaped, film-coated tablet, debossed with "150" on one side and "TMC" on the other side, contains 150 mg of darunavir (corresponding to darunavir ethanolate 162.62 mg). Nonmedicinal ingredients: colloidal silicon dioxide, crospovidone, magnesium stearate, and microcrystalline cellulose; film coating: polyethylene glycol, polyvinyl alcohol - partially hydrolyzed, talc, and titanium dioxide.

600 mg
Each orange, oval-shaped, film-coated tablet, debossed with "600MG" on one side and "TMC" on the other side, contains darunavir ethanolate equivalent to 600 mg of darunavir. Nonmedicinal ingredients: colloidal silicon dioxide, crospovidone, magnesium stearate, and microcrystalline cellulose; film coating: OPADRY II Orange (polyethylene glycol, polyvinyl alcohol - partially hydrolyzed, titanium dioxide, talc, sunset yellow FCF aluminum lake).

800 mg
Each dark red, oval-shaped, film-coated tablet debossed with "800" on one side and "T" on the other side contains darunavir ethanolate equivalent to 800 mg of darunavir. Nonmedicinal ingredients: colloidal silicon dioxide, crospovidone, hypromellose, magnesium stearate, and microcrystalline cellulose; Film coating: Opadry II Dark Red (polyethylene glycol, polyvinyl alcohol - partially hydrolyzed, titanium dioxide, talc, iron oxide red).

Oral Suspension
Each 1 mL of strawberry cream flavoured suspension contains 108.4 mg of darunavir ethanolate equivalent to 100 mg of darunavir. Nonmedicinal ingredients: hydroxypropyl cellulose, microcrystalline cellulose and carmellose sodium, sucralose, sodium methyl parahydroxybenzoate, masking flavour, citric acid monohydrate, and strawberry cream flavour.

Do not take darunavir if you:

• are allergic to darunavir or any ingredients of the medication
• are allergic to ritonavir
• have severe liver disease
• are taking any of the following medications:
• Alfuzosin
• Amiodarone
• Apixaban
• Colchicine
• Dronedarone
• elbasvir/grazoprevir
• ergot derivatives (e.g., Dihydroergotamine, ergonovine, ergotamine, methylergonovine)
• lidocaine
• Lovastatin
• Lurasidone
• midazolam
• Pimozide
• quinidine
• rifampin
• Rivaroxaban
• Sildenafil
• Simvastatin
• St. John's wort
• Triazolam

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

• abacavir
• Abiraterone
• Aliskiren
• Alitretinoin
• alpha blockers (e.g., alfuzosin, Doxazosin, Tamsulosin, Silodosin)
• amiodarone
• anti-cancer medications (e.g., Cabazitaxel, Docetaxel, Doxorubicin, Etoposide, Everolimus, Ifosfamide, Irinotecan, Vincristine)
• anti-emetic medications (serotonin antagonists; e.g., Granisetron, Ondansetron)
• antihistamines (e.g,. cetirizine, doxylamine, Diphenhydramine, Hydroxyzine, Loratadine, rupatadine)
• anti-psychotics (e.g., Chlorpromazine, Haloperidol, Olanzapine, Quetiapine, Risperidone)
• apixaban
• Aprepitant
• asunaprevir
• Atomoxetine
• "azole" antifungal agents (e.g., itraconazole, ketoconazole, Voriconazole)
• barbiturates (e.g., butalbital, Phenobarbital)
• benzodiazepines (e.g., Alprazolam, Diazepam, triazolam)
• beta-blockers (e.g., Carvedilol, Metoprolol, Propranolol)
• Bicalutamide
• birth control pills
• Bosentan
• Brinzolamide
• Bromocriptine
• Buspirone
• Calcitriol
• calcium channel blockers (e.g., Amlodipine, Diltiazem, Felodipine, Nifedipine)
• cannabis
• Captopril
• certain benzodiazepines (e.g., alprazolam, midazolam, triazolam)
• chloroquine
• colchicine
• conivaptan
• corticosteroids (e.g., budesonide, Dexamethasone, fluticasone)
• Cyclosporine
• dabigatran
• Dabrafenib
• Darifenacin
• Deferasirox
• Dextromethorphan
• diabetes medications (e.g., chlorpropamide, Gliclazide, Glyburide, insulin, Metformin, Rosiglitazone)
• didanosine
• Digoxin
• Disopyramide
• dofetilide
• Domperidone
• dronedarone
• Dutasteride
• Enzalutamide
• Eplerenone
• ergot alkaloids (e.g., dihydroergotamine, ergonovine, ergotamine, methylergonovine)
• estrogens (e.g., conjugated estrogen, Estradiol, ethinyl estradiol)
• Flecainide
• grapefruit juice
• Guanfacine
• hepatitis C antiviral combinations (e.g., ombitasvir/paritaprevir/ritonavir/dasabuvir, ombitasvir/paritaprevir/ritonavir)
• other HIV protease inhibitors (e.g., atazanavir, indinavir, ritonavir, saquinavir)
• HIV non-nucleoside reverse transcriptase inhibitors (NNRTIs; e.g., delavir\dine, efavirenz, etravirine, nevirapine)
• lidocaine
• Loperamide
• Losartan
• macrolide antibiotics (e.g., clarithromycin, erythromycin)
• maraviroc
• Mefloquine
• Methadone
• methamphetamine
• Mexiletine
• mifepristone
• Mirtazapine
• Modafinil
• nefazodone
• nitrates (e.g., isosorbide dinitrate,  isosorbide mononitrate)
• Omeprazole
• certain opioid narcotics (e.g., Fentanyl, methadone, Oxycodone, sufentanil)
• Orlistat
• Oxybutynin
• phosphodiesterase-5 inhibitors (e.g., sildenafil, taladafil, Vardenafil)
• Prasugrel
• praziquantel
• Primaquine
• procainamide
• progestins (e.g., Dienogest, Levonorgestrel, medroxyprogeterone, Norethindrone)
• Propafenone
• protein kinase inhibitors (e.g., Axitinib, Crizotinib, imatinib, Lapatinib)
• quinidine
• quinine
• rifabutin
• rifampin
• rilpivirine
• Riociguat
• rivaroxaban
• Romidepsin
• St. John's wort
• salmeterol
• seizure medications (e.g., Carbamazepine, Gabapentin, Levetiracetam, Phenytoin, Valproic acid)
• selective serotonin reuptake inhibitors (SSRIs; e.g., Citalopram, Paroxetine, Sertraline)
• simeprevir
• Sirolimus
• Solifenacin
• "statin" cholesterol-reducing medications (e.g., Atorvastatin, lovastatin, simvastatin)
• Tacrolimus
• tenofovir
• Tetrabenazine
• Theophylline
• Ticagrelor
• Ticlopidine
• Tocilizumab
• Tolterodine
• Tolvaptan
• Tramadol
• Trazodone
• tricyclic antidepressants (e.g., Amitriptyline, Clomipramine, Desipramine, Trimipramine)
• "triptan" migraine medications (e.g., Eletriptan, Sumatriptan)
• Ulipristal
• Venlafaxine
• Warfarin
• zidovudine
• Zolpidem
• Zopiclone

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 Prezista. 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 medication 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 Prezista.

Allergies: People who are allergic to sulfonamide medications may experience an allergic reaction to darunavir. Advise your doctor of any allergies to any medications before taking darunavir.

Bleeding: Darunavir may cause a reduced number of platelets in the blood, which can make it difficult to stop cuts from bleeding. If you notice any signs of bleeding, such as frequent nosebleeds, unexplained bruising, or black and tarry stools, notify your doctor as soon as possible. Your doctor will order routine blood tests to make sure potential problems are caught early.

Blood tests: Darunavir can cause changes in your blood test results, such as red blood cell count, platelet count, cholesterol level, and sugar level. Your doctor will explain these to you and monitor your blood levels.

Diabetes: Antiretroviral medications such as darunavir may increase blood sugar levels. If you have diabetes or are at risk for developing diabetes, discuss with your doctor how Prezista may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Prezista, and whether any special monitoring is required.

Fat redistribution: Over time, Prezista 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 you may notice loss of fat from the legs, arms, and face. The long-term effects of this are not known.

Immune reconstitution syndrome: Prezista may cause immune reconstitution syndrome, where signs and symptoms of inflammation from previous infections appear. These symptoms occur soon after starting anti-HIV medications and can vary. They are thought to occur as a result of the immune system improving and being able to fight infections that have been present without symptoms, such as pneumonia, herpes, or Tuberculosis. Report any new symptoms to your doctor immediately.

Liver problems: People with severe liver disease should not take darunavir. If you have mild to moderate liver disease, you can take Prezista and should discuss with your doctor how Prezista may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Prezista, and whether any special monitoring is required.

There have been reports of serious liver problems while taking darunavir. People with liver problems (including hepatitis B or Hepatitis C infection) are at a greater risk of experiencing serious liver problems while taking Prezista. Your doctor will monitor you and perform liver function tests regularly while you are taking Prezista. If you experience symptoms of liver problems (e.g., abdominal pain, persistent vomiting, feeling unwell, fever, itching, yellowing of the skin and eyes, dark urine), contact your doctor immediately.

Pancreatitis: Prezista may cause inflammation of the pancreas (pancreatitis). If you have a history of or are at risk for developing pancreatitis, you should be closely monitored by your doctor while taking Prezista. Discuss with your doctor how Prezista may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Prezista, and whether any special monitoring is required.

If you develop signs of pancreatitis (e.g., upper left abdominal pain, back pain, nausea, fever, chills, rapid heartbeat, swollen abdomen), contact your doctor.

Skin rashes: Prezista can cause skin rash, which is usually mild and moderate. However, darunavir can cause severe skin reactions. If you develop a skin rash with fever, fatigue, blisters, muscle aches, or sores in and around the mouth, stop taking Prezista and contact your doctor immediately.

Stopping the medication: If you stop taking Prezista, your HIV 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.

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

Breast-feeding: It is not known if darunavir passes into breast milk. However, since HIV can be transmitted by breast milk, women who have HIV are advised not to breast-feed.

Children: The safety and effectiveness of using Prezista have not been established for children less than 3 years of age or for children who have not taken any antiretroviral medication in the past. Prezista should not be given to children less than 3 years old due to the increased risk of severe side effects.