Final answer:
The common side effect of all immunosuppressant drugs that limits the dosage for long-term maintenance therapy is c) Nephrotoxicity.
Step-by-step explanation:
This condition refers to the toxic effect these drugs have on the kidneys, which can lead to impaired kidney function and is a well-known risk associated with the long-term use of these medications. Immunosuppressants are crucial for preventing organ rejection in transplant patients, for example, as they work by suppressing the immune system to prevent it from attacking the transplanted organ.
Side effects of immunosuppressive treatments can range in severity and may include systemic disorders such as hypertension, as well as more severe effects like impaired heart function or organ-specific issues. It's important to manage the dosage to minimize these risks while still providing therapeutic benefits to the patient, whether they are undergoing treatment for an autoimmune disease or following an organ transplant.