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

The following side effects have been reported by at least 1% of people taking Invirase. 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.

• Diarrhea
• dizziness
• drowsiness
• dry or itchy skin
• gas
• headache
• heartburn
• loss of appetite
• nausea
• tiredness
• 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:

• abdominal pain
• changes in body fat distribution (increased fat in the upper back and neck, breasts, and trunk; and loss of fat from the arms, legs, and face)
• fainting
• heart rhythm changes, sensation of abnormal heartbeats
• increased cholesterol and triglyceride levels
• lightheadedness
• mouth ulcers
• signs of Anemia (low red blood cells; e.g., dizziness, pale skin, unusual tiredness or weakness, shortness of breath)
• signs of clotting problems (e.g., unusual nosebleeds, bruising, blood in urine, coughing blood, bleeding gums, cuts that don't stop bleeding)
• signs of infection (symptoms may include Fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness)
• 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)
• signs of pancreatitis (e.g., abdominal pain on the upper left side, back pain, nausea, fever, chills, rapid heartbeat, swollen abdomen)
• symptoms of high blood sugar (e.g., frequent urination, increased thirst, excessive eating, unexplained weight loss, poor wound healing, infections, fruity breath odour)
• tingling or numbness
• weight loss

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

• signs of a serious allergic reaction (e.g., abdominal cramps, difficulty breathing, nausea and vomiting, or swelling of the face and throat)

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 Invirase.

Capsules

Each hard gelatin, light brown and green capsule imprinted with "Roche" and "0245" on opaque shells contains 200 mg of saquinavir as saquinavir mesylate. Nonmedicinal ingredients: lactose, magnesium stearate, microcrystalline cellulose, povidone, sodium starch glycolate, and talc; capsule shell: gelatin, indigotine, iron oxide, and titanium dioxide.

Tablets

Each light orange to greyish- or brownish-orange, oval cylindrical, biconvex, film-coated tablet with "ROCHE" and "SQV 500" imprinted on the tablet face contains 500 mg of saquinavir as saquinavir mesylate. Nonmedicinal ingredients: croscarmellose sodium, lactose, magnesium stearate, microcrystalline cellulose, and povidone K30; film-coat: hypromellose, iron oxide red, iron oxide yellow, talc, titanium dioxide, and triacetin.

Do not take saquinavir if you:

• are allergic to saquinavir or any ingredients of the medication
• have a history of problems with the electrical activity of the heart known as QT prolongation
• have a history of problems with electrolyte imbalances (especially low potassium levels in the blood)
• have severe liver problems
• are taking any of the following medications:
• Alfuzosin
• atazanavir
• antiarrhythmic medications (e.g., Amiodarone, Disopyramide, Flecainide, procainamide, Propafenone, quinidine, Sotalol, lidocaine)
• antipsychotic medications (e.g., Chlorpromazine, Clozapine, Haloperidol, Lurasidone, Pimozide, Quetiapine, Ziprasidone)
• astemizole
• cisapride
• ergot derivatives
• macrolide antibiotics (e.g., clarithromycin, erythromycin)
• midazolam
• quinine
• rifabutin
• rifampin
• rilpivirine
• Sildenafil (for pulmonary arterial hypertension)
• "statin" medications (e.g., Lovastatin, Simvastatin)
• Sunitinib
• Tacrolimus
• terfenadine
• Trazodone
• Triazolam

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

• Abiraterone acetate
• Aliskiren
• Almotriptan
• alpha blockers (e.g., alfuzosin, Doxazosin, Silodosin, Tamsulosin)
• amantadine
• antiarrhythmia medications (e.g., amiodarone, Dipyridamole, disopyramide, flecainide, procainamide, propafenone, quinidine, sotalol, lidocaine)
• anti-cancer medications (e.g., Cabazitaxel, Docetaxel; Doxorubicin; Etoposide, Ifosfamide, Irinotecan, Vincristine)
• antihistamines (e.g,. cetirizine, doxylamine, Diphenhydramine, Hydroxyzine, Loratadine)
• antimalarial medications (e.g., atovaquone, chloroquine, praziquantil, proguanil)
• antipsychotics (e.g., chlorpromazine, clozapine, haloperidol, Olanzapine, quetiapine, Risperidone)
• Apixaban
• Apomorphine
• Aprepitant
• "azole" antifungals (e.g., itraconazole, ketoconazole, Voriconazole)
• benzodiazepines (e.g., Chlordiazepoxide, Clonazepam, Diazepam, Lorazepam)
• birth control pills
• Bosentan
• Brinzolamide
• Bromocriptine
• Buprenorphine
• Buspirone
• Busulfan
• Calcitriol
• calcium channel blocking agents (e.g., Diltiazem, Felodipine, Amlodipine, verapamil, Flunarizine)
• cannabis
• Carbamazepine
• Carvedilol
• chloral hydrate
• cobicisat
• Colchicine
• conivaptan
• corticosteroids for the nose (e.g., fluticasone, mometasone)
• inhaled corticosteroids (e.g., budesonide, ciclesonide, fluticasone)
• oral corticosteroids (e.g., Dexamethasone, Hydrocortisone, Prednisone)
• Cyclosporine
• dabigatran
• daclatasvir
• Dantrolene
• Dapsone
• Darifenacin
• Deferasirox
• Degarelix
• diabetes medications (e.g., chlorpropamide, glipizide, Glyburide, insulin, Metformin, Rosiglitazone)
• Digoxin
• dofetilide
• Domperidone
• Dronedarone
• enfuvirtide
• Enzalutamide
• Eplerenone
• ergot alkaloids (e.g., Dihydroergotamine, ergonovine, ergotamine, methylergonovine)
• estrogens (e.g., conjugated estrogen, Estradiol, ethinyl estradiol)
• Everolimus
• Fesoterodine
• formoterol
• Galantamine
• Guanfacine
• H2 antagonists (e.g., Famotidine, Ranitidine)
• Hepatitis C antivirals (e.g., simeprevir)
• HIV non-nucleoside reverse transcriptase inhibitors (NNRTIs; e.g., delavirdine, efavirenz, etravirine, nevirapine)
• Indapamide
• Lacosamide
• ledipasvir
• lidocaine
• lithium
• Loperamide
• Lomitapide
• Losartan
• lurasidone
• macrolide antibiotics (e.g., clarithromycin, erythromycin)
• Macitentan
• Maprotiline
• Methadone
• netronidazole
• mifepristone
• Mirtazapine
• Modafinil
• Montelukast
• Nadolol
• certain narcotics (e.g., Fentanyl, Hydrocodone, Oxycodone)
• nefazodone
• nitrates (e.g., isosorbide dinitrate,  isosorbide mononitrate)
• Octreotide
• other HIV protease inhibitors (e.g., atazanavir, indinavir, ritonavir)
• Oxybutynin
• pentamidine
• Perampanel
• Phenobarbital
• Phenytoin
• phosphodiesterase 5 inhibitors (e.g., avanafil, sildenafil, Tadalafil, Vardenafil)
• Pimecrolimus
• primadone
• progestins (e.g., Dienogest, Levonorgestrel, medroxyprogesterone, Norethindrone)
• proton pump inhibitors (e.g., Lansoprazole, Omeprazole)
• Prucalopride
• protein kinase inhibitors (e.g,. Dasatinib, imatinib, Nilotinib, sunitinb)
• quinidine
• quinine
• quinolone antibiotics (e.g., ciprofloxacin, Norfloxacin, Ofloxacin)
• rifabutin
• rifampin
• rilpivirine
• Riociguat
• Rivaroxaban
• Romidepsin
• St. John's wort
• salmeterol
• selective serotonin reuptake inhibitors (SSRIs; e.g., Citalopram, Fluoxetine, Paroxetine, Sertraline)
• serotonin antagonists (anti-emetic medications; e.g., Granisetron, Ondansetron)
• siltuximab
• Sirolimus
• Solifenacin
• "statin" medications (e.g., Atorvastatin, lovastatin, simvastatin)
• sulfamethoxazole
• tacrolimus
• Tamoxifen
• Tetrabenazine
• Theophylline
• Ticagrelor
• Ticlopidine
• Tocilizumab
• Tolvaptan
• Tolterodine
• Tramadol
• trazodone
• tricyclic antidepressants (e.g., Amitriptyline, Clomipramine, Desipramine, Trimipramine)
• Trimethoprim
• Ulipristal
• Valproic acid
• Venlafaxine
• Warfarin
• zidovudine
• Zolpidem
• zonisamide
• 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 Invirase. 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 Invirase.

Abnormal heart rhythm: Saquinavir may cause a problem with the electrical activity of the heart known as QT prolongation, which can affect the heart's rhythm. While you are taking Invirase, your doctor will monitor your heart rhythm regularly with a test called an electrocardiogram (ECG). You should not take Invirase if your ECG already shows that you have QT prolongation or if you are taking a medication that can cause QT prolongation.

Certain medications (e.g., sotalol, quinidine, thioridazine, chlorpromazine, pimozide, moxifloxacin, Mefloquine, pentamidine, arsenic trioxide, tacrolimus) can increase the risk of a type of abnormal heart rhythm called QT prolongation, and should not be used in combination with saquinavir. You are more at risk for this type of abnormal heart rhythm and its complications if you:

• are female
• are older than 65 years of age
• have a family history of sudden cardiac death
• have a history of heart disease or abnormal heart rhythms
• have a slow heart rate
• have congenital prolongation of the QT interval
• have Diabetes
• have had a Stroke
• have low potassium, magnesium, or calcium levels
• have nutritional deficiencies

If you have heart disease and abnormal heart rhythms, or people are taking certain medications (e.g., Verapamil, atazanavir), discuss with your doctor how Invirase may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Invirase, and whether any special monitoring is needed.

Cholesterol: Invirase may increase cholesterol or triglyceride (another type of body fat) levels. Your doctor will regularly monitor your cholesterol levels while you are taking saquinavir.

Diabetes: Antiretroviral medications such as saquinavir may increase blood sugar levels. If you have diabetes, discuss with your doctor how Invirase may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Invirase, and whether any special monitoring is required.

Fat redistribution: Over time, Invirase may change how fat is distributed on your body and may change your body shape. With long-term use, you may notice increased fat on the stomach, upper back and neck, chest, stomach area, and breasts. Fat may be reduced on your arms, legs, and face. The long-term effects of this are not known. Notify your doctor if you start developing any changes in your body's appearance.

Foods: Fatty foods and grapefruit juice increase the body's absorption of saquinavir.

Galactose intolerance: Saquinavir medications are prepared with lactose. If you have lactose or galactose intolerance you should not take these medications.

Hemophilia: People with hemophilia may have an increased risk of bleeding while taking Invirase. If you have hemophilia, discuss with your doctor how Invirase may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Invirase, and whether any special monitoring is needed.

Immune reconstitution syndrome: Invirase 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 function: Saquinavir can cause serious liver problems, including liver failure and rarely, death. If you are taking saquinavir, your doctor may request that you have regular liver function tests while you are taking Invirase. Invirase may also cause a decrease in liver function. If you experience symptoms of liver problems such as fatigue, feeling unwell, loss of appetite, nausea, yellowing of the skin or whites of the eyes, dark urine, pale stools, abdominal pain or swelling, and itchy skin, contact your doctor immediately.

People with severely impaired liver function should not take saquinavir.

Other medications: Saquinavir may interact with a number of medications, which may mean a change in how you take Invirase (See "What medications can interact with Invirase?"). Tell your doctor of all medications that you are taking. Certain medications should not be taken with saquinavir at all (see "Who should not take Invirase?"). Saquinavir should never be used on its own and should always be used in combination with ritonavir and other HIV medications.

Pancreatitis: Saquinavir can cause the pancreas to become inflamed. If you have a history of pancreatitis, gallstones, Alcoholism, or high triglycerides, you may be more at risk of experiencing this. If you have a history of pancreatitis, discuss with your doctor how Invirase may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Invirase, and whether any special monitoring is needed.

Report signs of pancreatitis such as abdominal pain on the upper left side, back pain, nausea, fever, chills, rapid heartbeat, or swollen abdomen to your doctor immediately.

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

Breast-feeding: It is not known if saquinavir passes into breast milk. Because HIV can be transmitted by breast milk, breast-feeding is not recommended for women who are HIV-positive.

Children: The safety and effectiveness of using Invirase have not been established for children younger than 16 years of age.