Common side effects of Risperdal include dizziness, fatigue, fever, and nausea. Within the list of moderate to severe side effects that have been reported in connection with Risperdal are abdominal pain, constipation, diarrhea, vomiting, long-lasting erection, anxiety, agitation, coughing, dry mouth, blurred vision, chest pain, decreased activity, quickened pulse, itching, inhibited coordination, insomnia, joint pain, and other conditions.
Weight gain is associated with Risperdal and has more specifically presented in cases of gynecomastia — a benign enlarging of the breast tissue in males. In adolescent boys, this development can be a source of intense psychological distress as a result of lowered self-esteem.
Diabetes mellitus type 2 is another side effect associated with Risperdal. It is a metabolic disorder characterized by a relative lack of insulin or insulin resistance that results in high blood sugar, or hyperglycemia. Type 2 diabetes accounts for approximately 90 percent of all diabetes cases.
Bone loss is another side effect of Risperdal. This occurs within the lifelong cycle of bone absorbance and creation when more old bone is reabsorbed than new bone is created. This imbalance causes bones to become weak and brittle, making people more prone to injury.
Another known side effect of Risperdal is tardive dyskinesia — an involuntary movement disorder that is difficult to treat and often incurable. This form of dyskinesia is characterized by a slow onset and results in purposeless, involuntary, repetitive movements, such as lip smacking, grimacing, and excessive eye blinking.
Pituitary tumors have been known to develop in connection with Risperdal, which can cause both excessive production of hormones that otherwise help regular normal body functions and lower levels of hormones to produce due to restricted normal functions of the pituitary gland. Although pituitary tumors are generally noncancerous and remain confined within the local area, the pituitary gland is located near the optic nerve, and tumors can result in eye problems and headaches.
Neuroleptic malignant syndrome may also result from Risperdal. This life-threatening neurological disorder is often a direct reaction to an antipsychotic drug. Symptoms include delirium or similar cognitive agitation, fever, muscle rigidity, and autonomic instability.
In the case of older adults with dementia, Risperdal presents an increased risk of death. Death generally results from stroke in the case of such patients. Strokes occur when the brain is deprived of oxygen and food as a result of reduced or interrupted blood flow, which thereby causes brain cells to die and damages the brain tissue.
Older patients suffering from dementia who take Risperdal are also at greater risk of heart failure and pneumonia.