Yes. Medication errors that occur in the hospital setting can involve everything from over the counter (OTC) drugs to powerful chemotherapy and painkilling medication that can be deadly if administered at the wrong dosage.
What's more, medication errors can occur at any number of different stages in the treatment process. The wrong medicine might be prescribed or ordered in the first place; there might be a miscommunication somewhere along the line between prescription and administration of the medication; the incorrect dosage (too much or too little) might be given to the patient; or the patient might not be properly monitored after administration of the medication. Any of these missteps can be actionable as the basis for a medical malpractice lawsuit if the error ends up harming the patient.
But what will you need to prove in order to prove your medication error case? While the facts of every case are different, you'll first need to prove that a health care professional (your doctor, a pharmacist, an anesthesiologist, etc.) failed to act with the level of care that a similarly-trained and knowledgeable health care professional would have demonstrated under similar circumstances. Second, you'll need to establish that the provision of that sub-standard care was the actual cause of your harm.
In situations involving medication errors where the patient suffered significant harm, it's a good idea to discuss the case with an experienced medical malpractice attorney. These cases are complex from a proof standpoint -- they typically involve the testimony of expert medical witnesses and the presentation of complicated medical evidence.
To get an understanding of the hurdles you'll need to overcome to bring a medical malpractice case, see The Challenges in Winning a Medical Malpractice Lawsuit.