Long-term use of medications for bipolar disorder can impact several organs in the body. Here are some of the key organs that may be affected:

Liver: Many mood stabilizers and antipsychotic medications are metabolized by the liver, which can lead to liver function abnormalities or damage over time. Regular monitoring of liver enzymes is often recommended.
Kidneys: Lithium, a common medication used to treat bipolar disorder, can affect kidney function with long-term use. Regular kidney function tests are important for those on lithium therapy.
Thyroid: Lithium can also impact thyroid function, potentially leading to hypothyroidism (underactive thyroid). Thyroid levels should be monitored regularly.
Heart: Some antipsychotic medications can affect heart health by causing changes in heart rhythm (QT prolongation) or contributing to weight gain and metabolic syndrome, which increase cardiovascular risk.
Pancreas: Certain mood stabilizers and antipsychotics may increase the risk of developing diabetes mellitus by affecting blood sugar levels and insulin sensitivity.
Gastrointestinal System: Medications like valproate (Depakote) can cause gastrointestinal issues such as nausea, vomiting, or pancreatitis in some individuals.
Bone Marrow: Some medications used for bipolar disorder might rarely cause bone marrow suppression, leading to decreased production of blood cells.
Skin and Hair: Certain medications might cause dermatological side effects like rashes or hair loss (alopecia).

Regular medical check-ups and laboratory tests are essential for monitoring these potential side effects when taking long-term medication for bipolar disorder. Always discuss any concerns with your healthcare provider so they can tailor your treatment plan accordingly.