You went to the doctor, trusting him or her to cure your ailment. The doctor gave you a medication and told you it would likely work.
It didn't. In fact, it led to complications, and your initial condition also progressed while you were taking a medication that wasn't doing you any good. You feel far worse now, and it's clear that your doctor failed.
Is that enough for a lawsuit? It may be, but it might not be enough to hold up all on its own.
Doctors can't be held to impossible standards. They can't cure every disease or even save every life. They try, but they do fail.
People often think of medicine as an exact science, but it's actually not in a lot of cases. Doctors have to use trial and error. You got one medication, but the doctor may have had five options that have all worked in similar cases. He or she may decide to simply try one and change things up if it doesn't click.
The key to starting a lawsuit is negligence. If the doctor gave you proper care and just failed to find a cure right away, that's not negligence. If the doctor made mistakes that could easily have been avoided, however, failing to give you the high level of care that you deserve, then you might have a case.
For instance, perhaps the doctor mixed up the paperwork and gave you a medication intended for another person. Clear errors like that show that you were wronged as a patient. Make sure you know what legal options you have.
Source: FindLaw, "Doctor Prescribed the Wrong Medication: Can I Sue?," Ephrat Livni, accessed Feb. 01, 2018