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Daclatasvir

Daclatasvir: Generic Medication Overview

Daclatasvir is an antiviral medication used to treat chronic hepatitis C virus (HCV) infection. It is available as a generic drug and is marketed under brand names such as Daklinza (Bristol Myers Squibb) and various other generic labels worldwide. In the United Kingdom, daclatasvir is a prescription-only medicine and is supplied as a 60 mg oral pill.

How Daclatasvir Works in the Body

Daclatasvir belongs to the class of NS5A inhibitors. The NS5A protein is a non-structural component of HCV that plays a crucial role in viral RNA replication and the assembly of new virus particles. By binding to the NS5A protein, daclatasvir:

• Disrupts the formation of the replication complex, halting viral RNA synthesis.
• Interferes with the assembly of infectious virions, reducing the amount of virus released into the bloodstream.

The drug is rapidly absorbed after oral administration, reaching peak plasma concentrations within 2-4 hours. It has a long half-life of approximately 12-15 hours, supporting once-daily dosing. Daclatasvir is extensively metabolised by the liver, primarily via the cytochrome P450 3A4 (CYP3A4) pathway, and is expelled mainly in the feces.

Conditions Treated by Daclatasvir

In the UK, daclatasvir is approved for the treatment of chronic hepatitis C infection when used in combination with other direct-acting antivirals (DAAs) such as sofosbuvir, plus, where appropriate, ribavirin. The approved regimens vary according to:

• HCV genotype (e.g., genotype 1, 2, 3, 4, 5, or 6).
• Presence of cirrhosis (compensated or decompensated).
• Prior treatment experience (treatment-naïve or previously treated).

Typical therapeutic goals are to achieve a sustained virologic response (SVR), defined as undetectable HCV RNA 12 weeks after completing therapy, which is considered a cure.

Patient Suitability and Contraindications

Who Should Use Daclatasvir?

• Adults with chronic HCV infection who meet the specific genotypic and disease-stage criteria set out in national treatment guidelines.
• Patients for whom the selected combination regimen (e.g., daclatasvir + sofosbuvir) is appropriate based on liver function and prior therapy.

Absolute Contraindications

• Known hypersensitivity to daclatasvir or any of the tablet’s excipients.

Relative Contraindications / Precautions

• Severe hepatic impairment (Child-Pugh class C): Daclatasvir is not recommended because safety and efficacy have not been established.
• Pregnancy and Breast-feeding: Limited data exist; the drug should be avoided unless the potential benefit outweighs the risk to the fetus.
• Co-administration with strong CYP3A4 inducers (e.g., rifampicin, carbamazepine, St John’s wort): These agents markedly reduce daclatasvir exposure and are contraindicated.
• Co-administration with strong CYP3A4 inhibitors (e.g., ritonavir, cobicistat): Dose adjustment or avoidance may be required; clinicians should consult current guidance.

Safety Profile: Side Effects and Interactions

Common Side Effects

• Fatigue (commonly reported)
• Headache
• Nausea
• Diarrhoea

These effects are usually mild to moderate and tend to improve as treatment continues. Patients should stay hydrated and report persistent or worsening symptoms to their prescriber.

Serious Adverse Events

• Elevated liver enzymes (ALT/AST) indicating possible hepatic injury.
• Severe skin reactions such as Stevens-Johnson syndrome, though extremely rare.

If any sign of severe allergic reaction (e.g., rash, swelling, difficulty breathing) occurs, seek urgent medical attention.

Drug Interactions

• Major Interactions: Strong CYP3A4 inducers (rifampicin, phenytoin, barbiturates) can reduce daclatasvir plasma levels, leading to loss of antiviral efficacy. Avoid concomitant use.
• Moderate Interactions: Strong CYP3A4 inhibitors (ritonavir, cobicistat) increase daclatasvir exposure. When combined with these agents, a dose reduction to 30 mg once daily is recommended, but this adjustment should be made by a healthcare professional.
• P-gp/BCRP Substrates: Daclatasvir is a substrate of P-glycoprotein (P-gp) and breast-cancer-resistance protein (BCRP); inhibitors of these transporters (e.g., amiodarone) may modestly raise daclatasvir concentrations.

Food and Lifestyle Interactions

• Food: Daclatasvir can be taken with or without meals; no significant food effect has been demonstrated.
• Alcohol: Excessive alcohol consumption can worsen underlying liver disease. Patients should discuss alcohol use with their clinician.
• Driving: No impairment of mental or physical abilities has been reported; however, patients experiencing fatigue should use caution when operating machinery.

Dosing and Administration Guidelines

• Standard dose: 60 mg tablet taken orally once daily, with or without food.
• Combination therapy: Daclatasvir is always prescribed as part of a regimen that includes other DAAs (e.g., sofosbuvir) and, when indicated, ribavirin. The total treatment duration typically ranges from 8 to 24 weeks, depending on genotype and liver disease status.
• Renal impairment: No dose adjustment is required for patients with renal dysfunction, including those on dialysis.
• Hepatic impairment: Use the standard 60 mg dose for patients with mild or moderate hepatic impairment (Child-Pugh A or B). Avoid use in Child-Pugh C.
• Missed dose: Take the missed tablet as soon as remembered on the same day; do not double the next dose.
• Overdose: Symptoms may include nausea, vomiting, dizziness, and rapid heart rate. Seek immediate medical assistance; supportive care is the mainstay of treatment.

Monitoring and Follow-Up

• Baseline assessments: HCV genotype, liver function tests (ALT, AST, bilirubin), complete blood count, renal function, and pregnancy testing for women of child-bearing potential.
• During therapy: Periodic HCV RNA measurements (e.g., at weeks 4 and 12) to confirm viral suppression, and regular liver function monitoring.
• End of treatment: Evaluate for SVR 12 weeks after therapy completion (SVR12). A sustained undetectable viral load confirms cure.

Storage and Handling

• Store tablets at room temperature (15-30 °C), away from moisture and direct sunlight.
• Keep the container tightly closed and out of reach of children.
• Do not use tablets after the printed expiry date; discard any unused medication according to local pharmacy guidelines.

Medication-Specific Glossary

NS5A Inhibitor

A class of antivirals that block the NS5A protein of hepatitis C virus, preventing viral replication and assembly.

Sustained Virologic Response (SVR)

The absence of detectable HCV RNA in the blood 12 weeks (or more) after finishing antiviral therapy, regarded as a cure.

P-Glycoprotein (P-gp)

A transport protein that pumps many drugs out of cells; inhibition can raise concentrations of P-gp substrates like daclatasvir.

BCRP (Breast-Cancer-Resistance Protein)

Another cellular transporter affecting drug absorption and elimination; daclatasvir is a substrate.

Medical Disclaimer

This article provides educational information about daclatasvir and is not a substitute for professional medical advice. Treatment decisions, including the use of daclatasvir for unapproved indications, must be made under the guidance of a qualified healthcare provider. The content is intended for informational purposes and does not constitute medical recommendations. Always consult a physician before starting, stopping, or changing any medication regimen.