AULA DE FARMACOLOGIA - Interações medicamentosas com Anti-inflamatórios não esteroidais (AINES)

Summary

This video explores the complexities of drug interactions, focusing on how certain medications like lithium, antidepressants, and NSAIDs (non-steroidal anti-inflammatory drugs) interact with each other. The lecturer highlights the potential risks, such as increased bleeding and adverse effects from combining SSRIs (selective serotonin reuptake inhibitors) with NSAIDs. Additionally, the video discusses the role of serotonin in platelet aggregation and its impact on overall drug metabolism through the cytochrome P450 enzyme system. Aimed at healthcare professionals and students, the content offers insights into managing these interactions safely and effectively.

Takeaways

• 😀 Anti-inflammatory drugs (AINEs) can cause various side effects including vomiting, nausea, diarrhea, abdominal pain, muscle weakness, lethargy, dizziness, and edema, especially in the lower limbs.
• 😀 Anti-inflammatory drugs (AINEs) may have an additive effect on the risk of bleeding when combined with antidepressants due to their impact on platelet aggregation.
• 😀 The use of AINEs and lithium simultaneously may lead to additional complications due to lithium's impact on bodily functions, requiring careful monitoring.
• 😀 Antidepressants, especially selective serotonin reuptake inhibitors (SSRIs) like fluoxetine and paroxetine, increase serotonin levels in the brain, which helps reduce depressive symptoms but can affect platelet function.
• 😀 SSRIs, including fluoxetine, sertraline, and paroxetine, work by increasing the concentration of monoamines (dopamine, serotonin, and norepinephrine) in the synaptic cleft to alleviate depression.
• 😀 Many SSRIs inhibit liver enzymes such as CYP2D6, CYP1A2, CYP3A4, and CYP2C19, which affects the metabolism of other drugs, including AINEs.
• 😀 Patients using paroxetine or fluoxetine should be cautious when taking AINEs due to the potential for excessive anti-inflammatory effects and increased risk of side effects.
• 😀 SSRIs have long half-lives, often over 10 hours, with some like fluoxetine having a half-life of up to 5 days, which influences their metabolic interactions with other medications.
• 😀 Inhibiting CYP enzymes with SSRIs can alter how other drugs, including AINEs, are metabolized, potentially leading to increased toxicity or diminished effectiveness of those drugs.
• 😀 Special caution should be taken by individuals using SSRIs continuously, particularly paroxetine, to avoid excessive bleeding risks when taking AINEs.
• 😀 The platform 'Farmacologia Aplicada R2' offers further learning opportunities for those interested in understanding pharmacology in a more engaging, dynamic way.

Q & A

What are the main side effects associated with the use of lithium, as mentioned in the transcript?

The main side effects associated with lithium include vomiting, nausea, diarrhea, polydipsia (excessive thirst), abdominal pain, muscle weakness, lethargy, dizziness, speech difficulties (dysarthria), impaired motor coordination (dysmetria), edema (particularly in the lower limbs), and hyperreflexia. These effects serve as warnings for individuals using lithium in combination with other medications.

What is the role of antidepressants in the treatment of depression, according to the script?

Antidepressants are used to treat depression by increasing the concentration of monoamines, particularly serotonin, in the brain. The theory of depression suggests that a decrease in monoamine levels, especially serotonin, leads to depressive symptoms. Antidepressants work by inhibiting the reuptake of these monoamines, particularly serotonin, which alleviates depressive symptoms.

How do selective serotonin reuptake inhibitors (SSRIs) function in the body?

SSRIs function by inhibiting the reuptake of serotonin into the presynaptic neuron, which increases the amount of serotonin available in the synaptic cleft. This leads to an improvement in mood and reduction of depressive symptoms. Some SSRIs are more selective for serotonin, while others also affect other neurotransmitters to a lesser degree.

What are the common SSRIs mentioned in the transcript?

The common SSRIs mentioned in the transcript are citalopram, fluoxetine, sertraline, and paroxetine. These medications are used to increase serotonin levels in the brain and help alleviate symptoms of depression.

What is the significance of the half-life of SSRIs, and which SSRI has a notably long half-life?

The half-life of SSRIs is significant because it affects the duration and consistency of their action in the body. A long half-life ensures that the drug stays active in the body for an extended period. For example, fluoxetine has a notably long half-life of about 5 days, which means it takes longer for the drug to be eliminated from the body.

How do SSRIs affect the cytochrome P450 (CYP450) enzyme system?

SSRIs, such as paroxetine and fluoxetine, can inhibit the cytochrome P450 enzyme system, particularly certain isoforms like CYP2D6, CYP1A2, CYP3A4, and CYP2C19. This inhibition can slow the metabolism of other drugs that are processed by these enzymes, leading to increased drug levels in the body.

Why is it important to be cautious when using anti-inflammatory drugs (AINEs) with antidepressants?

It is important to be cautious when using AINEs with antidepressants because many AINEs are metabolized by the same cytochrome P450 enzymes that SSRIs inhibit. This can lead to higher levels of AINEs in the body, increasing the risk of side effects such as gastrointestinal distress and bleeding. SSRIs can also affect platelet function, which compounds the risk of bleeding when combined with AINEs.

What are the risks of combining paroxetine or fluoxetine with AINEs?

Combining paroxetine or fluoxetine with AINEs increases the risk of bleeding due to their effect on serotonin and platelet aggregation. Since serotonin is involved in platelet function, these antidepressants can impair the blood's ability to clot, making individuals more susceptible to bleeding, especially in cases of injury or trauma.

What is the impact of SSRIs on platelet aggregation?

SSRIs impact platelet aggregation because serotonin is involved in platelet activation. By increasing serotonin levels, SSRIs can alter platelet function, making it more difficult for blood to clot properly. This increases the risk of bleeding, particularly when combined with medications like AINEs, which also affect platelet function.

How should patients using both antidepressants and AINEs be monitored?

Patients using both antidepressants, particularly paroxetine and fluoxetine, and AINEs should be closely monitored for signs of excessive bleeding or gastrointestinal distress. Careful attention should be paid to any injuries, bruising, or signs of internal bleeding. Healthcare providers may adjust medication dosages or recommend alternative therapies to mitigate these risks.