Farmacologia em Populações especiais

Summary

This lecture focuses on pharmacology in special populations, such as pregnant women, lactating mothers, children, and the elderly. It discusses the unique vulnerabilities these groups face when using medications, including the physiological changes that affect drug absorption, metabolism, and excretion. A key example is the tragic case of a newborn who died due to an overdose of morphine from maternal codeine use. The lecture covers the safety considerations for medication use in these populations, highlighting risks, regulatory categories, and the importance of personalized care and careful drug choice to avoid adverse effects.

Takeaways

• 😀 Special populations in pharmacology include pregnant women, lactating women, pediatric patients, and the elderly.
• 😀 Pharmacology in special populations presents challenges due to physiological differences that affect drug absorption, distribution, metabolism, and excretion.
• 😀 Drugs used during pregnancy can cross the placenta and impact fetal development, as seen in the thalidomide tragedy of the 1960s, which led to regulatory changes in drug safety.
• 😀 The FDA classifies drugs into five categories based on their risk to fetal development, ranging from A (low risk) to X (contraindicated due to known risks).
• 😀 Medications used during lactation require careful consideration, as some drugs, like codeine, can pass into breast milk and harm the infant, potentially leading to respiratory depression or death.
• 😀 Pediatric patients have unique drug safety concerns due to their developmental stages, with varying physiological characteristics across age groups, making them highly vulnerable to drug toxicity and inefficacy.
• 😀 Dosage calculations for pediatric patients are typically based on adult doses adjusted for weight and age, but it is crucial to prioritize medications studied in pediatric populations.
• 😀 In geriatrics, polypharmacy is common, increasing the risk of adverse drug reactions, drug interactions, and hospitalization due to the vulnerability of older adults to drug side effects.
• 😀 Physiological changes in the elderly, such as decreased renal function, liver metabolism, and altered drug distribution, require careful drug dose adjustments and monitoring.
• 😀 Certain medications, such as benzodiazepines (e.g., diazepam) and NSAIDs, are considered potentially inappropriate for older adults due to increased risks of cognitive decline, falls, and gastrointestinal issues.
• 😀 A multidisciplinary approach involving healthcare professionals is essential when managing drug therapy for special populations to ensure optimal safety and therapeutic outcomes.

Q & A

Why are certain populations considered special in pharmacology?

Certain populations, such as pregnant women, lactating women, children, and elderly individuals, are considered special in pharmacology due to their unique physiological characteristics that may affect how medications are absorbed, distributed, metabolized, and excreted, making them more vulnerable to adverse drug reactions.

What was the cause of death in the clinical case involving a newborn described in the lecture?

The newborn's death was attributed to a morphine overdose, which was a result of the mother's use of codeine. Codeine is metabolized into morphine, and when it passed into the mother's breast milk, it caused respiratory depression and ultimately led to the infant's death.

How does pregnancy affect drug metabolism?

Pregnancy can alter drug metabolism due to physiological changes such as increased body water, which may dilute drug concentrations, as well as changes in liver and kidney function. These alterations can necessitate dose adjustments to achieve the desired therapeutic effect.

What tragic event led to increased regulatory scrutiny on drug safety during pregnancy?

The tragedy of thalidomide in the 1960s, which caused birth defects in thousands of babies, led to increased regulatory scrutiny on drug safety during pregnancy and the establishment of risk categories for drugs used during pregnancy.

What are the FDA's pregnancy drug categories, and what do they represent?

The FDA has five pregnancy drug categories: A, B, C, D, and X. Categories A and B indicate the lowest risk of harm to the fetus, while categories C, D, and X represent increasing levels of risk, with category X indicating drugs that should not be used during pregnancy due to strong evidence of harm.

How can medications affect breastfeeding women and their infants?

Medications taken by breastfeeding mothers can pass into breast milk and affect the infant. Some medications may cause adverse reactions such as respiratory depression, while others may reduce milk production. Therefore, careful consideration and risk-benefit analysis are necessary before prescribing medications to lactating women.

What is the primary concern when administering drugs to pediatric patients?

The primary concern when administering drugs to pediatric patients is that children are not just small adults; they have different physiological characteristics. These differences, along with age-specific variations in drug absorption, distribution, metabolism, and excretion, require tailored dosing and careful monitoring.

What is the significance of the immaturity of the hepatic enzyme system in neonates?

The immaturity of the hepatic enzyme system in neonates results in slower drug metabolism, which can lead to the accumulation of drugs in the body, increasing the risk of adverse reactions. This is one of the factors that contributed to the fatal overdose in the clinical case discussed.

Why are elderly individuals at higher risk for adverse drug reactions?

Elderly individuals are at higher risk for adverse drug reactions due to several factors, including reduced liver and kidney function, changes in body composition (such as increased fat and decreased water content), and the common occurrence of polypharmacy (use of multiple medications), which increases the potential for drug interactions and side effects.

What are some examples of medications that are considered inappropriate for elderly patients?

Examples of medications that are considered inappropriate for elderly patients include benzodiazepines (like diazepam), nonsteroidal anti-inflammatory drugs (NSAIDs), tricyclic antidepressants (like amitriptyline), and certain muscle relaxants (like cyclobenzaprine). These medications can increase the risk of sedation, falls, cognitive decline, and other adverse effects.