Street drugs and the various medicines used to treat hepatitis C generally don’t interact with one another. Glancing at the University of Liverpool’s HEP Drug Interactions checker, there were no interactions listed between cannabis, cocaine, ecstasy, meth or oxycodone and the most common hep C treatments. Heroin isn’t listed, but fentanyl may interact with a few HCV medications.
Note that some medical providers as well as state Medicaid and insurance plans may require drug testing as a condition for hep C treatment. Not only is this unethical, there is no medical basis for this. Research shows that people who use street drugs and take their hep C medicines as prescribed have favorable outcomes.
Ideally, it would be healthier to live without drugs. If you use drugs that have an overdose risk, learn how to reduce that risk. For instance, learn how to use Narcan (naloxone), and try to use drugs only in situations where Narcan is available.