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

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

• Constipation
• back pain
• changes in mood or emotions
• Diarrhea
• difficulty sleeping or nightmares
• headache
• loss of appetite
• nausea
• stomach pain
• tiredness or fatigue
• trembling
• 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 check with your doctor or seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• any mouth sores
• cold or flu-like symptoms (such as Fever or sore throat)
• fever
• headache
• high blood pressure
• nightmares
• pallor (paleness of skin)
• palpitations (unusual heartbeats that may cause a pounding or fluttering feeling in the chest)
• possible signs of cancer (e.g., a sore that does not heal; changes in bladder or bowel habits; lumps or thickened areas on the breast or other body areas; night sweats; severe, persistent Headaches; swollen glands; trouble swallowing, unexplained stomach upset, nagging cough or hoarseness; unusual bleeding or discharge)
• rapid heartbeat
• shortness of breath or difficulty breathing
• signs of kidney problems (e.g., increased urination at night, decreased urine production, blood in the urine)
• 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 progressive multifocal leukoencephalopathy (e.g., personality changes, progressive weakness on one side of the body, changes in memory, confusion)
• signs of posterior encephalopathy syndrome (e.g., headache, seizures, visual disturbances, altered mental state)
• signs of reduced red blood cells (e.g., fatigue, general feeling of being unwell, weakness, dizziness, fainting, pale skin, pale stool)
• swelling or tingling in your hands or feet
• symptoms of high blood sugar (e.g., frequent urination, increased thirst, excessive eating, unexplained weight loss, poor wound healing, infections, fruity breath odour)
• symptoms of a urinary tract infection (e.g., pain when urinating, urinating more often than usual, low back or flank pain)
• vision changes

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

• chest pain
• convulsions (seizures)
• signs of a hole in the digestive system (e.g., severe abdominal pain, burning pain, nausea, vomiting, chills or fever)
• signs of a severe skin reaction such as blistering, peeling, a rash covering a large area of the body, a rash that spreads quickly, or a rash combined with fever or discomfort

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 Tacrolimus.

0.5 mg
Each white-to-off-white powder-filled, size “4” capsule, with a light-yellow opaque body imprinted with “Z” in black and light yellow cap imprinted with “0.5 mg” in black, contains tacrolimus 0.5 mg. Nonmedicinal ingredients: croscarmellose sodium, hypromellose, lactose monohydrate, magnesium stearate. Capsule shell: gelatine, titanium dioxide and yellow iron oxide. Printing ink: black iron oxide, butyl alcohol, dehydrated alcohol, isopropyl alcohol, potassium hydroxide, propylene glycol, shellac, strong ammonia, and water.

1 mg
Each white-to-off-white powder-filled, size “4” capsule with white opaque body imprinted with “Z” in black and white cap imprinted with “1 mg” in black, contains tacrolimus 1 mg.  Nonmedicinal ingredients: croscarmellose sodium, hypromellose, lactose monohydrate, magnesium stearate. Capsule shell: gelatine, and titanium dioxide. Printing ink: black iron oxide, butyl alcohol, dehydrated alcohol, isopropyl alcohol, potassium hydroxide, propylene glycol, shellac, strong ammonia, and water.

5 mg
Each white-to-off-white powder-filled, size “3” capsule with Swedish-orange-coloured opaque body imprinted with “Z” in black, and Swedish-orange-coloured cap imprinted with “5 mg” in black contains tacrolimus 5 mg. Nonmedicinal ingredients: croscarmellose sodium, hypromellose, lactose monohydrate, magnesium stearate. Capsule shell: gelatine, titanium dioxide, and red iron oxide. Printing ink: black iron oxide, butyl alcohol, dehydrated alcohol, isopropyl alcohol, potassium hydroxide, propylene glycol, shellac, strong ammonia, and water.

Do not take Tacrolimus if you are allergic to tacrolimus or any ingredients of the medication.

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

• Acarbose
• alcohol
• Aliskiren
• Amiodarone
• antacids (e.g., aluminum hydroxide, magnesium carbonate)
• antifungal medications (e.g., ketoconazole, Clotrimazole, itraconazole, fluconazole, Voriconazole)
• antihistamines (e.g., cetirizine, doxylamine, Diphenhydramine, Hydroxyzine, Loratadine)
• antipsychotics (e.g., Chlorpromazine, Clozapine, Haloperidol, Olanzapine, Quetiapine, Risperidone)
• Aprepitant
• barbiturates (e.g., butalbital, Phenobarbital)
• BCG
• Bosentan
• Bromocriptine
• calcium channel blockers (e.g., Diltiazem, Verapamil, Nifedipine)
• Carbamazepine
• Carvedilol
• Celecoxib
• chloroquine
• Cinacalcet
• Cobicistat
• Colchicine
• conivaptan
• corticosteroids (e.g., Dexamethasone, Hydrocortisone, Prednisone)
• Cyclosporine
• daclatasvir
• Danazol
• Deferasirox
• Denosumab
• diabetes medications (e.g., chlorpropamide, Glyburide, insulin, Metformin, Rosiglitazone)
• Disopyramide
• dofetilide
• Domperidone
• Dronedarone
• echinacea
• Enzalutamide
• Eplerenone
• Fenofibrate
• Fingolimod
• Flecainide
• "gliptin" diabetes medications (e.g., Linagliptin, Saxagliptin, Sitagliptin)
• grapefruit juice
• H2 antagonists (e.g., Famotidine, Ranitidine)
• HIV non-nucleoside reverse transcriptase inhibitors (NNRTIs; e.g., delavirdine, efavirenz, etravirine, nevirapine)
• HIV protease inhibitors (e.g., atazanavir, indinavir, ritonavir, saquinavir)
• Leflunomide
• macrolide antibiotics (e.g., erythromycin, clarithromycin)
• medications to treat cancer (e.g., Carboplatin, Cyclophosphamide, Doxorubicin, Ifosfamide, Vincristine)
• Methadone
• Methotrexate
• Metoclopramide
• mifepristone
• Modafinil
• nefazodone
• non-steroidal anti-inflammatory medications (NSAIDs; e.g., Diclofenac, Ibuprofen, Naproxen)
• Oxcarbazepine
• Phenytoin
• Pimecrolimus
• potassium-sparing diuretics (e.g., Amiloride, Spironolactone, triamterene)
• primidone
• procainamide
• Propafenone
• protein kinase inhibitors (e.g., Bosutinib, Crizotinib, Dabrafenib, imatinib, Nilotinib, Sunitinib)
• proton pump inhibitors (e.g., Lansoprazole, Omeprazole)
• quinidine
• quinine
• quinolone antibiotics (e.g., ciprofloxacin, Norfloxacin, Ofloxacin)
• rifabutin
• rifampin
• rilpivirine
• Roflumilast
• St. John's wort
• selective serotonin reuptake inhibitors (SSRIs; e.g., Citalopram, Fluoxetine, Paroxetine, Sertraline)
• serotonin antagonists (anti-emetic medications; e.g., Granisetron, Ondansetron)
• sevelamer
• Sildenafil
• siltuximab
• Sirolimus
• Sotalol
• "statin" cholesterol lowering medications (e.g., Atorvastatin, Lovastatin, Simvastatin)
• Tetrabenazine
• Tocilizumab
• Tofacitinib
• Trastuzumab
• tricyclic antidepressants (e.g., Amitriptyline, Clomipramine, Desipramine, Trimipramine)
• vaccines
• Vardenafil

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 Tacrolimus. 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 Tacrolimus.

Abnormal heart rhythms: Tacrolimus may cause a heart rhythm problem called QT prolongation. If you have a history of QT prolongation, slow or irregular heartbeat, irregular heart rhythm, heart failure, Heart Attack, heart disease, taking other medications known to cause QT prolongation, or a family history of sudden cardiac death at less than 50 years of age, discuss with your doctor how Tacrolimus may affect your medical condition, or how your medical condition may affect the dosing and effectiveness of Tacrolimus. Your doctor will perform tests at regular intervals to monitor for any changes in your heart rhythm.

Blood pressure: Tacrolimus treatment commonly causes mild-to-moderate increases in blood pressure. Monitor your blood pressure, and inform your doctor if there is an indication that your blood pressure is rising.

Diabetes: Tacrolimus may cause an increase in blood sugar levels and glucose tolerance may change. People with diabetes may find it necessary to monitor their blood sugar more frequently while using Tacrolimus. Your doctor will help to monitor this, but be sure to report any signs of high blood sugar (e.g., increased thirst, urination, unusual tiredness) to your doctor.

If you have diabetes or are at risk for developing diabetes, discuss with your doctor how Tacrolimus may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Tacrolimus, and whether any special monitoring is needed.

High potassium levels in the blood: Tacrolimus may cause an increase in potassium levels in the blood. Some foods (e.g., bananas or orange juice) and some medications may increase the risk of this problem. Be sure to tell your doctor and pharmacist about all the medications you are taking (including non-prescription medications) and to talk to them about potassium-rich foods.

Infections: Tacrolimus reduces resistance to infections and may delay healing. Ensure proper treatment to avoid infection (e.g., dental work, skin injury). Avoid activities that increase the risk of infection.

Because tacrolimus reduces the body’s response to infection, conditions caused by bacteria or viruses that have been dormant in the body, such as chicken pox, hepatitis B, or Tuberculosis may be reactivated.

Tell your doctor immediately if you notice signs of an infection, such as fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness.

Kidneys: Tacrolimus may affect kidney function. Your doctor will monitor your kidney function with laboratory tests while you are taking Tacrolimus. Be sure to immediately report to your doctor any evidence of changes in kidney function such as changes in the appearance of urine, frequency of urination, and amount of urine produced.

Liver function: Liver disease or reduced liver function may cause Tacrolimus to build up in the body, causing side effects. If you have liver problems, discuss with your doctor how Tacrolimus may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Tacrolimus, and whether any special monitoring is needed. Your doctor may want to test your liver function regularly with blood tests while you are taking Tacrolimus.

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.

Lymphoma and other malignancies: People taking immunosuppressant medications, such as tacrolimus, are at increased risk of developing a type of cancer known as lymphoma and certain types of Skin Cancer. This risk is related to the intensity and duration of treatment with immunosuppressant medications rather than to one specific medication.

Possible warning signs of cancer include a change in bowel or bladder habits, sores that don’t heal, unusual bleeding, change in appearance of a wart or mole, night sweats, a nagging cough or persistent and severe headaches. If you experience any of these, let your doctor know right away. This may help to detect any cancers early in their development.

Nerves: Tacrolimus may affect nerve function and cause symptoms such as tremors and headaches. Be sure to report any changes to your doctor at once.

Red blood cell aplasia: Tacrolimus has been reported to cause the body to stop producing red blood cells. If you experience symptoms of reduced red blood cell count such as shortness of breath, feeling unusually tired or pale skin, contact your doctor as soon as possible.

Reversible posterior leukoencephalopathy syndrome (RPLS): This is a rare disease of the brain that can occur when using tacrolimus. Make sure your doctor knows if you have experienced this condition before. If you experience signs and symptoms of RPLS, such as headache, seizures, change in awareness or consciousness or vision changes, contact your doctor immediately.

Pregnancy: Adequate studies have not been conducted on the use of tacrolimus by pregnant women. Reports of the use of tacrolimus during pregnancy has been associated with high blood potassium levels and kidney problems in the newborn.

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

Breast-feeding: Tacrolimus passes into breast milk. Breast-feeding is not recommended while taking tacrolimus. If you are a breast-feeding mother and taking tacrolimus, it may affect your baby. Talk to your doctor.

Tacrolimus belongs to the class of medications called immunosuppressants. It is used in addition to other medications to prevent the body's rejection of an allogeneic (from a donor) transplanted kidney, liver, or heart or treat the body's rejection of a transplanted kidney or liver.

It may also be used to treat Rheumatoid Arthritis when the usual therapies have failed to work. Tacrolimus works by lowering the activity of white blood cells in the body (the cells that attack substances foreign to the body).

Tacrolimus may be available under multiple brand names and/or in several different forms. Any specific brand name of Tacrolimus may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of Tacrolimus may not be used for all of the conditions discussed here.

Your doctor may have suggested Tacrolimus for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking Tacrolimus, speak to your doctor. Do not stop taking Tacrolimus without consulting your doctor.

Do not give Tacrolimus to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take Tacrolimus if their doctor has not prescribed it.