Some Antipsychotic Drugs

Some Antipsychotic Drugs

Some Antipsychotic Drugs are Risperidone, Procyclidine Hydrochloride, Aripiprazole, Sertraline Hydrochloride, etc. Drug knowledge like Indication, Contraindication, Mode of Action, Doses form, Doses, Side effects of these drugs are mentioned here.

Risperidone

Risperidone is an oral or injectable atypical antipsychotic medication used to treat conditions such as schizophrenia, bipolar I disorder, and irritability associated with autism. It works by balancing levels of dopamine and serotonin in the brain. 

Key Uses

Risperidone is FDA-approved for: 

• Schizophrenia in adults and adolescents aged 13 and older.
• Bipolar I disorder (manic or mixed episodes), used alone or with other mood stabilizers like lithium or valproate, in adults and children aged 10 and older.
• Irritability associated with autistic disorder in children and adolescents aged 5 to 16. 

It may also be used off-label for other conditions like Tourette syndrome or as an adjunct in treatment-resistant depression. 

Available Forms

Risperidone is available in several forms: 

• Standard oral tablets
• Oral solution (liquid)
• Orally disintegrating tablets (which dissolve quickly on the tongue)
• Long-acting injections (intramuscular or subcutaneous) administered by a healthcare provider every 2 to 8 weeks, depending on the specific product. 

Important Safety Information & Side Effects

Risperidone can cause side effects and carries important warnings. 

Boxed Warning

Older adults with dementia-related psychosis treated with antipsychotic medications such as risperidone have an increased risk of death and stroke. Risperidone is not approved for this use. 

Common Side Effects

• Drowsiness or feeling tired
• Weight gain and increased appetite
• Movement problems like tremors, restlessness (akathisia), or muscle stiffness
• Headaches
• Dizziness, especially when standing up quickly
• Nausea, vomiting, or constipation
• Increased prolactin levels, which can lead to breast enlargement or discharge, and missed menstrual periods 

Serious Side Effects

• Neuroleptic Malignant Syndrome (NMS): A rare but life-threatening condition involving high fever, severe muscle stiffness, confusion, and irregular heartbeat.
• Tardive Dyskinesia (TD): A movement disorder that may become permanent, causing uncontrollable movements of the face, tongue, or body.
• High Blood Sugar: Can increase the risk of developing diabetes; symptoms include extreme thirst and frequent urination.
• Orthostatic Hypotension: A significant drop in blood pressure when changing position, leading to dizziness and a risk of falls. 

Precautions and Interactions

• Alcohol: Avoid drinking alcohol as it can increase drowsiness and other side effects.
• Pregnancy and Breastfeeding: Discuss risks and benefits with a doctor; newborns exposed during the third trimester may experience withdrawal symptoms.
• Medical Conditions: Inform your doctor if you have kidney, liver, or heart problems, diabetes, or a history of seizures.
• Other Medications: Risperidone can interact with other drugs, including certain antidepressants, blood pressure medications, and Parkinson’s disease medications. 

Always take risperidone exactly as prescribed by your doctor and do not stop taking it abruptly without medical supervision, as this can cause symptoms to return or lead to withdrawal effects.

Aripiprazole

Aripiprazole (brand name examples: Abilify, Abilify Maintena) is an atypical antipsychotic medication used to treat various mental health conditions by helping to restore the balance of natural substances (dopamine and serotonin) in the brain. 

Key Uses

Aripiprazole is used alone or as an adjunct (add-on) treatment for several conditions: 

• Schizophrenia in adults and adolescents.
• Bipolar I disorder (manic-depressive illness), specifically manic or mixed episodes, and for maintenance treatment.
• Major depressive disorder, used as an adjunctive treatment with other antidepressants.
• Irritability associated with autistic disorder in children and adolescents.
• Tourette syndrome. 

Administration and Dosage Forms

Aripiprazole is available in several forms: 

• Oral tablets
• Oral solution (liquid)
• Orally disintegrating tablets (dissolves quickly in the mouth)
• Oral films
• Intramuscular injection (short-acting for agitation, and extended-release/depot injections for maintenance). 

Dosage is determined by a doctor and depends on the specific condition being treated and the patient’s response. 

Common Side Effects

Common side effects often improve over time as the body adjusts to the medication. 

• Difficulty sleeping (insomnia)
• Anxiety and restlessness
• Headache
• Nausea and vomiting
• Constipation
• Feeling sleepy or fatigued
• Blurred vision 

Important Considerations

• Prescription only: Aripiprazole is a prescription-only medication and is not a controlled substance.
• Monitoring: Patients should be closely monitored during treatment. Your doctor may need to perform lab tests.
• Pathological gambling: A potential risk of compulsive behaviors, including pathological gambling, has been associated with aripiprazole.

Mode of action of Aripiprazole

Aripiprazole works as a dopamine/serotonin system stabilizer, acting as a partial agonist at dopamine D2 and serotonin 5-HT1A receptors, meaning it activates them but less strongly than full agonists, and an antagonist at serotonin 5-HT2A receptors, blocking them. This unique “dopamine system stabilization” allows it to both increase dopamine activity in underactive brain areas (like the prefrontal cortex, helping with negative symptoms) and decrease it in overactive areas (like the limbic system, helping with positive symptoms of psychosis). 

Key Actions on Neurotransmitters:

• Dopamine D2 Receptors: Partial agonist; increases dopamine signaling when levels are low, decreases it when levels are high.
• Serotonin 5-HT1A Receptors: Partial agonist; helps regulate serotonin release.
• Serotonin 5-HT2A Receptors: Antagonist; blocks these receptors, which can help alleviate negative symptoms and reduce extrapyramidal side effects (movement issues). 

How it Stabilizes Brain Activity:

• In High-Dopamine Areas (e.g., Mesolimbic Pathway): Acts like a “brake,” reducing excessive dopamine activity linked to hallucinations and delusions.
• In Low-Dopamine Areas (e.g., Mesocortical Pathway): Acts like an “accelerator,” boosting dopamine activity to improve motivation and cognition. 

This balanced approach makes it effective for treating symptoms of schizophrenia, bipolar disorder, and major depressive disorder with fewer typical antipsychotic side effects like prolactin elevation or motor issues (EPS). 

Relation between Aripiprazole and Prolactin

Aripiprazole generally lowers elevated prolactin levels, making it useful for treating high prolactin caused by other antipsychotics, though it’s less likely to raise it initially. Its unique mechanism as a dopamine partial agonist helps normalize prolactin by balancing dopamine’s effects, especially at lower doses, but some case reports show it can paradoxically raise prolactin in rare instances, often at higher doses. 

How it works

• Dopamine Partial Agonism: Aripiprazole acts as a partial agonist at dopamine D2 receptors, meaning it stimulates dopamine activity but less intensely than full agonists.
• Reduces High Prolactin: By boosting dopamine at D2 receptors, it counteracts the dopamine blockade caused by other antipsychotics, thereby reducing prolactin release from the pituitary gland.
• Dose-Dependent Effects: Its beneficial effect on lowering prolactin seems to be more pronounced at lower doses (e.g., <5mg) and may plateau or even paradoxically increase levels at higher doses, according to some findings. 

Clinical Use

• Add-on Treatment: It’s commonly used as an add-on to normalize prolactin in patients already on risperidone or paliperidone.
• Effective & Rapid: Studies show it can significantly reduce prolactin levels, often within a week, bringing them back to normal ranges. 

Potential Paradoxical Effects

• While rare, some patients experience symptoms of high prolactin (hyperprolactinemia) with aripiprazole, possibly due to dose-related effects or individual variability, say this study on springermedizin.de and this study on nih.gov. 

In summary, aripiprazole is a valuable tool for managing antipsychotic-induced hyperprolactinemia, effectively normalizing levels by modulating dopamine, though its dose and individual response require monitoring.