Daclatasvir belongs to the class of medications called antiviral agents. This medication is used by adults, in combination with other antiviral medications to treat chronic (long-term), hepatitis C virus infections with hepatitis C genotypes 1, 2, or 3. It works by preventing the action of a specific protein that the virus needs to reproduce.

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

Your doctor may have suggested this medication 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 this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

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

The recommended adult dose of daclatasvir is 60 mg taken by mouth once a day. It must be taken with another antiviral medication such as sofosbuvir. Ribavirin may also be added to this combination, however daclatasvir should not be taken with only ribavirin. Depending on the type of hepatitis C virus you have and other characteristics of your illness, your doctor may recommend that you take this medication for 12 to 24 weeks.

Daclatasvir may be taken with food or on an empty stomach.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed by your doctor. If you miss a dose, and remember less than 20 hours after the scheduled dose, take it as soon as possible and continue with your regular schedule. If it is less than 4 hours until your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature in the original container. Protect it from light and moisture, and keep it out of the reach of children.

Do not take this medication if you:

• are allergic to daclatasvir or any ingredients of the medication
• are taking certain other medications, which include, but are not limited to
• carbamazepine
• dexamethasone
• oxcarbazepine
• phenobarbital
• phenytoin
• rifabutin
• rifampin
• rifapentine
• St. John's wort

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

The following side effects have been reported by at least 1% of people taking this medication. 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
• headache
• nausea
• rash
• tiredness
• trouble sleeping

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:

• signs of anemia (low red blood cells; e.g., dizziness, pale skin, unusual tiredness or weakness, shortness of breath)
• slowed heart rate

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 this medication.

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 this medication.

Diabetes: People with diabetes may experience loss of glucose control while taking daclatasvir. This may mean your blood glucose levels are unusually high or low. If you have diabetes, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this mediation, and whether any special monitoring is needed. You should testing your blood glucose level more frequently while you are taking this medication.

Galactose intolerance: Daclatasvir is prepared with lactose. If you have lactose or galactose intolerance you should not take this medication.

Hepatitis B reactivation: People who have hepatitis B infection that is dormant may experience the infection returning, causing further liver dysfunction or liver failure. If you have a history of hepatitis B infection, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this mediation, and whether any special monitoring is needed.

If you experience symptoms of worsening liver function, 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.

Pregnancy: If you are not taking ribavirin, talk to your doctor about birth control. Effective birth control should be used while you are taking daclatasvir and for at least 5 weeks after stopping this medication.

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

Breast-feeding: It is not known if daclatasvir passes into breast milk. If you are a breast-feeding mother and are taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children. 

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

• aliskiren
• amiodarone
• anticancer medications (e.g., doxorubicin, etoposide, idarubicin, irinotecan, paclitaxel)
• antihistamines (e.g., bilastine, cetirizine, desloratadine, loratadine)
• antipsychotics (e.g., haloperidol, paliperidone, risperidone)
• aprepitant
• bosentan
• buprenorphine
• calcium channel blockers (e.g., amlodipine, diltiazem, nifedipine, verapamil)
• carbamazepine
• carvedilol
• cobicistat
• colchicine
• conivaptan
• cyclosporine
• dabigatran
• deferasirox
• dexamethasone
• diabetes medications (e.g., chlorpropamide, glyburide, insulin, metformin, rosiglitazone)
• digoxin
• dronedarone
• edoxaban
• elagolix
• enzalutamide
• eslicarbazepine
• estrogens (e.g., conjugated estrogen, estradiol, ethinyl estradiol)
• everolimus
• grapefruit juice
• other hepatitis C antivirals (e.g., grazoprevir, ledipasvir, voxilaprevir)
• HIV non-nucleoside reverse transcriptase inhibitors (NNRTIs; e.g., delavirdine, efavirenz, etravirine, nevirapine)
• HIV protease inhibitors (e.g., atazanavir, indinavir, ritonavir, saquinavir)
• hydrocortisone
• ivermectin
• lomitapide
• loperamide
• lumacaftor
• macrolide antibiotics (e.g., clarithromycin, erythromycin)
• methotrexate
• mifepristone
• mitotane
• modafinil
• morphine
• nadolol
• naloxegol
• norfloxacin
• ondansetron
• phenobarbital
• phenytoin
• primidone
• certain protein kinase inhibitors (e.g., bosutinib, dabrafenib, dasatinib, imatinib, pazopanib)
• prucalopride
• quinidine
• quinine
• ranitidine
• rifabutin
• rifampin
• rifaximin
• riociguat
• rivaroxaban
• romidepsin
• St. John's wort
• silodosin
• siltuximab
• sirolimus
• "statin" anti-cholesterol medications (e.g., atorvastatin, lovastatin, simvastatin)
• stiripentol
• tacrolimus
• tocilizumab
• tolvaptan
• warfarin

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 this medication. 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.