Pharm in older people

Excretion and Metabolism in Older Adults

• Excretion and Metabolism
  • Poor metabolism in older adults leads to increased incidence of toxic drug interactions because of the inefficiency in breaking down medications.
  • Older adults exhibit:
  • Volume Depletion: Decreased total body water results in higher likelihood of dehydration.
    • Increased risk of electrolyte imbalances due to diuretics and hydration issues.

Diuretics

• Definition: Medications that induce urination, often prescribed for edema.
• Mechanism:
  • They not only remove fluid but can also affect electrolyte balance by pulling electrolytes into urine, or in some cases, reinstating electrolytes to the bloodstream.

Postural Hypotension (Orthostatic Hypotension)

• Definition: A drop in blood pressure when standing up too quickly, leading to dizziness or fainting.
  • Common among older adults due to:
  • Dehydration and low blood volume affecting blood pressure.
  • Systolic blood pressure may increase when sitting but is prone to drop when standing.
  • Use of antihypertensive medications further complicates blood pressure stability.

Age-Related Changes in Pharmacodynamics

• Older adults experience:
  • Reduced sensitivity in specific receptors, diminishing responsiveness to hormones and medications.
  • Example: Epinephrine may not increase heart rate as effectively due to reduced receptor sensitivity.
  • This necessitates cautious dosing as a higher dose may lead to toxicity.

Pharmacokinetics in Older Adults

• Absorption:
  • Slower absorption times due to delayed gastric emptying.
  • Decreased gastric acid production reduces the ability to absorb certain medications effectively.
• Distribution:
  • Low Plasma Protein Levels:
  • Older adults have decreased levels of plasma proteins, affecting drug distribution.
  • Two highly protein-bound drugs may compete for binding, leading to drug interactions.
• Metabolism:
  • Decreased Liver Function:
  • Liver size shrinks, resulting in reduced blood flow and impaired metabolism of drugs.
  • Requires monitoring liver enzymes, particularly for drugs known to affect liver function.
• Excretion:
  • Reduced Kidney Functioning:
  • Decreased capacity for drug elimination, leading to higher chances of toxic drug accumulation.
  • Monitor BUN (Blood Urea Nitrogen) and creatinine for renal function.

Risks of Medication in Older Adults

• Polypharmacy:
  • Older patients often prescribed multiple medications from various specialists, increasing the risk of interactions and adverse effects.
• Adverse Drug Reactions and Events:
  • Increased susceptibility to medication errors and therapeutic failures due to complex regimens and overlapping prescriptions.
• Non-Adherence:
  • Factors leading to non-adherence include fear of asking questions, medical jargon misunderstanding, and challenges in following complex dosing schedules.
• Overdosing and Withdrawal:
  • Due to complex regimens, older individuals may unintentionally overdose or face withdrawal symptoms, which can be more severe and harder to manage.

Best Practices for Medication Management in Older Adults

• Medication Reconciliation:
  • Review all medications at admission and discharge. Use a comprehensive list to keep track of medications and medical history.
• Education:
  • Ensure understanding by using simple language and providing large print materials.
  • Teach patients the significance of medication timings and dosages, and encourage the use of pill organizers.
• Communication with Healthcare Providers:
  • Patients should convey their full medication history to each physician, and prescriptions should ideally be filled through a single pharmacy to check for potential interactions.
• Addressing Vision and Hearing Issues:
  • Make sure visual and auditory aids are in use to support effective communication and comprehension.

Monitoring and Evaluation

• Ongoing assessment of medication effectiveness and side effects should be a standard part of follow-up appointments.

• Healthcare providers must maintain awareness of the physiological changes associated with aging when prescribing or administering medications.

• Key Lab Values for Renal Function:

  • Monitor BUN and creatinine levels as reliable indicators of kidney health, rather than relying solely on electrolyte levels.

Conclusion

• Managing medications in older adults necessitates a comprehensive understanding of pharmacokinetic and pharmacodynamic changes, along with the importance of communication, education, and careful medication management to avoid adverse events.