Antipsicóticos típicos (1a geração) | Aula 26 | Farmacologia do SNC rápida e fácil

Summary

This video explains the role of first-generation antipsychotic medications, commonly used in treating schizophrenia and other conditions. It covers the two types of first-generation antipsychotics—high-potency and low-potency—and their mechanisms of action, primarily through blocking dopamine receptors. The script highlights the therapeutic effects and the associated side effects, including extrapyramidal symptoms, hormonal imbalances, and the risk of neuroleptic malignant syndrome. The video also explores the complex nature of dopamine pathways in the brain and how these drugs interact with various neurotransmitter receptors, ultimately affecting both positive and negative symptoms of psychosis.

Takeaways

• 😀 First-generation antipsychotics (neuroleptics) are mainly used to treat schizophrenia but have other uses as well.
• 😀 These medications are divided into high-potency and low-potency groups, each with different effects and side effects.
• 😀 High-potency antipsychotics, like haloperidol, are effective at lower doses but tend to cause more side effects, including motor issues.
• 😀 Low-potency antipsychotics, like chlorpromazine, cause fewer motor side effects but may lead to sedation, weight gain, and hypotension.
• 😀 Antipsychotics work by blocking dopamine receptors, especially D2 receptors, which helps alleviate positive symptoms like hallucinations and delusions.
• 😀 However, blocking dopamine receptors can worsen negative symptoms (e.g., lack of motivation, social withdrawal) in patients with schizophrenia.
• 😀 First-generation antipsychotics can cause extrapyramidal side effects, such as tremors, rigidity, and tardive dyskinesia, due to their effect on dopamine pathways.
• 😀 These drugs can also raise prolactin levels, leading to side effects like menstrual irregularities, sexual dysfunction, and lactation.
• 😀 They are contraindicated for people with Parkinson’s disease as they worsen motor symptoms by further reducing dopamine in the nigrostriatal pathway.
• 😀 Antipsychotics have a variety of side effects depending on their affinity for different receptors (e.g., muscarinic, adrenergic, histaminic), leading to symptoms like dry mouth, blurred vision, and sedation.
• 😀 While first-generation antipsychotics are effective in treating positive schizophrenia symptoms, their use is limited due to significant side effects and contraindications.

Q & A

What are first-generation antipsychotics also known as?

First-generation antipsychotics are also known as typical or conventional antipsychotics, sometimes referred to as neuroleptics.

What is the primary therapeutic use of first-generation antipsychotics?

First-generation antipsychotics are primarily used in the treatment of schizophrenia, a chronic psychotic disorder, but they can also be used for other psychotic conditions.

How are first-generation antipsychotics classified?

First-generation antipsychotics are classified into two groups: high-potency and low-potency. High-potency drugs have stronger effects at lower doses but may cause more side effects.

Can you name some examples of high-potency first-generation antipsychotics?

Examples of high-potency first-generation antipsychotics include haloperidol, flufenazine, and trifluoperazine.

What is the role of dopamine in schizophrenia and how do first-generation antipsychotics interact with it?

Dopamine is a neurotransmitter involved in various brain functions. In schizophrenia, dopamine dysregulation, especially in the mesolimbic pathway, contributes to positive symptoms like hallucinations. First-generation antipsychotics primarily work by blocking dopamine D2 receptors, reducing these symptoms.

What are the potential side effects of first-generation antipsychotics due to their action on the nigrostriatal pathway?

Blocking dopamine in the nigrostriatal pathway can lead to extrapyramidal symptoms (EPS) such as dystonia (muscle spasms), akathisia (restlessness), and tardive dyskinesia (involuntary movements). These are related to motor control and are common side effects of first-generation antipsychotics.

What is neuroleptic malignant syndrome (NMS), and how is it related to first-generation antipsychotics?

Neuroleptic malignant syndrome (NMS) is a rare but serious side effect of first-generation antipsychotics, characterized by fever, muscle rigidity, altered mental status, and autonomic instability. It can be life-threatening and requires immediate medical attention.

How do low-potency first-generation antipsychotics differ from high-potency ones in terms of side effects?

Low-potency first-generation antipsychotics generally cause fewer extrapyramidal side effects but may result in other adverse effects, including sedation, weight gain, and anticholinergic effects like dry mouth, constipation, and blurred vision.

What are some common adverse effects associated with the blocking of D2 receptors in the tuberoinfundibular pathway?

Blocking D2 receptors in the tuberoinfundibular pathway can lead to elevated levels of prolactin, which can cause symptoms like galactorrhea (abnormal milk production), amenorrhea (absence of menstruation), and sexual dysfunction.

Why are first-generation antipsychotics contraindicated in patients with Parkinson’s disease?

First-generation antipsychotics are contraindicated in patients with Parkinson’s disease because they block dopamine receptors in the nigrostriatal pathway, which can exacerbate motor symptoms of Parkinson’s disease, such as tremors and rigidity.

What is the primary goal of second-generation antipsychotics compared to first-generation drugs?

The primary goal of second-generation antipsychotics was to reduce the side effects associated with first-generation drugs, especially extrapyramidal symptoms (EPS) and prolactin elevation, while maintaining therapeutic efficacy for psychosis.