While risperidone can be effective in treating these disorders, you should be aware of the potential side effects before starting treatment. While many of the side effects are manageable, others may be serious and, in rare cases, life-threatening.
Risperidone Dosage
Risperidone is the generic name for this medication, which is available under the brand name Risperdal in oral tablets, liquid solutions, or injectable suspension forms. The oral dose of risperidone usually ranges between 1 mg and 6 mg per day. The injectable dose ranges between 12.5 mg and 50 mg per day. In most cases, people begin at a low dose that gradually increases until the desired therapeutic effects are achieved.
Common Side Effects
Risperdal can cause side effects for a variety of reasons. Because the drug has antihistaminic properties (similar to older antihistamine drugs), it may have a sedating effect in some people. It also acts as an alpha-adrenergic blocker, which interferes with certain hormones that regulate blood flow and blood pressure. Because of these properties, Risperdal may cause the following side effects in at least one percent of users:
Agitation Amenorrhea (absent period) Anxiety Arthralgia (joint pain) Asthenia (physical weakness and lack of energy) Blurred vision Constipation Cough Diarrhea Epistaxis (nosebleeds) Dizziness Dyspnea (shortness of breath) Excessive salivation Fatigue Galactorrhea (milky breast discharge) Gynecomastia (male breast enlargement) Hirsutism (abnormal hair growth in women) Increased appetite Indigestion Myalgia (muscle pain) Nausea and vomiting Nasal congestion Painful intercourse in women Rash Retrograde ejaculation (ejaculation of semen into the bladder rather than out of the body) Seborrhea (a scaly, patchy skin condition) Somnolence (sleepiness or drowsiness) Sore throat Sleep disturbances Suicidal thoughts Upper abdominal pain Upper respiratory tract infection Urinary incontinence Weight gain Xerostomia (dry mouth)
Extrapyramidal Side Effects
Extrapyramidal side effects (EPS) are those that affect the central nervous system and cause movement problems. EPS can affect as many as one of every four people who take risperidone, although most cases are relatively mild. For more mental health resources, see our National Helpline Database.
Types of EPS
Tardive dyskinesia is among the most common EPS experienced by Risperdal users. It is characterized by involuntary and repetitive movements, including those of the face, mouth, tongue, arms, or legs. These may include lip-smacking, grimacing, making chewing motions, rocking, rotating the ankles or legs, marching in place, sticking out the tongue, or making repetitive sounds such as humming or grunting. Other types of EPS include:
Akathisia (a feeling of inner restlessness and inability to stay still, often referred to as the “rabbit syndrome”) Akinesia (loss or impairment of voluntary movement) Dystonic reactions (intermittent and involuntary contractions of the muscles of the face, neck, trunk, pelvis, and extremities) Parkinsonism (a group of neurological disorders that cause movement problems similar to Parkinson’s disease, including tremors, slow movement, and stiffness)
Risk Factors
The risk of EPS is largely dose-dependent. Similarly, the type of formulation you take can also influence your risk. By way of example:
Oral formulations of risperidone are associated with a 2% to 12% risk of tremors, while intramuscular injections carry a three percent to 24% risk of the same.Depending on the formulation, depending on the formulation, tardive dyskinesia will affect anywhere from 2% to 6% of Risperdal users.Parkinsonism can affect as few as 6% to as many as 28% of users.
Serious Side Effects
On rare occasions, exposure to atypical antipsychotics may result in a potentially life-threatening reaction known as a neuroleptic malignant syndrome (NMS). It is a condition characterized by the following symptoms:
Altered mental stateHigh fever (over 100.4 F)Loss of bladder controlMuscle rigidityProfuse sweatingRespiratory problemSeizuresTachycardia (rapid heartbeat)
Once symptoms appear, they progress rapidly and can persist for anywhere from eight hours to over a month. For reasons unknown, NMS tends to affect men under 40 more than any other group. NMS is considered a medical emergency and can lead to death if left untreated. Treatment would be administered in an intensive care unit, often with mechanical ventilation, intravenous fluids, and various medications used to reduce muscle rigidity, agitation, and other symptoms.
Other Serious Complications
Other rare but potentially life-threatening side effects may occur with Risperdal use. Most are associated with either overuse or long-term use of the drug. They include:
Diabetic ketoacidosis (a dangerous build-up of acids in the blood)Pancreatitis (inflammation of the pancreas)Pulmonary embolism (the formation of a blood clot in the lungs)StrokeSudden cardiac death
In one study, approximately 80% of participants experienced improvements in schizophrenia symptoms.
