New medications called direct-acting antivirals (DAAs) have transformed the treatment of hepatitis C. Twelve weeks on one of these drugs cures the infection in 95 percent or more of people who take it.

But what if you’re among the 5 percent for whom they don’t work?

If your treatment doesn’t work, your doctor will put you on another medication or combination of drugs. The key is to keep trying treatments until you find the one that clears your infection.

Sticking with treatment until you achieve a cure will help you avoid hepatitis complications like cirrhosis and liver cancer.

The main way to treat hepatitis C today is with DAAs. These drugs block a protein that the virus needs to grow.

There are several different DAAs and combinations of these medications. A blood test will match you with the right drug by your genotype — the virus strain that caused your infection.

Most people stay on these medications for 8 to 24 weeks. How long you take DAAs depends on your genotype, how much liver damage you have, and whether you were treated for hepatitis C in the past.

Your doctor will order blood tests during and after your treatment to check whether the medication has cleared your infection.

No sign of the virus in your blood 12 weeks or more after you finish treatment is called a sustained virologic response (SVR). It means that your infection is cured.

DAAs cure hepatitis C in 95 percent or more of people who take them, but that means that about 5 percent won’t get an SVR.

With almost 2.4 million people living with hepatitis C in the United States, around 120,000 people can expect their treatment to fail.

Hepatitis C treatment can fail for a few reasons. Some causes are under your control, while others aren’t. Here are some of the most common reasons why these treatments don’t work:

  • Not staying on the medication. DAAs have to be taken consistently in order to cure a hepatitis C infection. People may stop taking their medication for a variety of reasons, including side effects, cost, and forgetfulness.
  • Relapse. Sometimes, people have an SVR when they finish treatment, only for the virus to become detectable again. This is called relapsing. Only a small percentage of people relapse, but it can be disappointing to learn that the virus has come back.
  • Virus resistance. Resistance means that the virus has stopped responding to the antiviral medication. Resistance is common in people who don’t achieve an SVR. Once someone is resistant to a certain direct-acting antiviral drug, it may not work if they try it again in the future.
  • Cirrhosis. Over the years, hepatitis C inflammation causes permanent damage and scarring of the liver, called cirrhosis. Treatment failure rates are 15 to 20 percent higher in people with cirrhosis.
  • Genotype 3. About 10 percent of people with hepatitis C have a genotype 3 infection. This genotype is more likely to lead to cirrhosis and liver cancer than other genotypes. It also doesn’t respond as well to treatment.

If antiviral medications don’t clear your infection the first time or you have a relapse, your doctor can change the dose, start you on a different medication, or add another medication.

A typical second treatment is to combine DAAs that target a different protein than the drug you took before.

Sofosbuvir (Sovaldi) is a common choice for people who don’t respond to their first DAA. It works against many hepatitis C genotypes, and it’s less likely to make the virus resistant than other drugs.

Treating a stubborn case of hepatitis C can be frustrating. Even if the first treatment you tried didn’t work or the virus became resistant to medication, it’s still possible for you to achieve an SVR.

Hepatitis C in some people is just harder to cure, and you may be one of them. Don’t get discouraged. Your doctor has many other medications to choose from.

You’ll be more likely to have success when you take your medication as prescribed. If you tend to forget your pills or you’ve had side effects that bother you, ask your doctor for advice to help you stay on your treatment plan.

Along with staying on your medication, try to take good care of your liver. Focus on eating a nutritious diet and avoiding alcohol and chemicals like insect killers and paint thinners, which can damage the liver.

It’s important to care for your emotional health, too. Living with a chronic disease can be stressful. Getting plenty of sleep, exercising on most days, and managing your stress can all help you manage your condition. If you can’t do it alone, ask for help from a trained therapist or counselor.

New direct-acting antivirals cure hepatitis C in most people who take them. If you’ve tried one of these medications and it didn’t work, that doesn’t mean you’re stuck with the virus forever. You just need to try another treatment approach.

Your next step could be to go on a different drug or try a combination of medications to attack the virus from different angles. Eventually, you should find the therapy that cures your hepatitis C.