Pharma Chap 27

Why is aging so important in Pharmacology?

The aging process is an individualized matter. Because of genetic or environmental factors or good health practices, some older adults may not feel or appear particularly different.

However, there are gradual changes in body composition and organ function as we grow older. These changes can affect the reaction to drugs and make the individual more sensitive to a wide variety of medications

How does aging affect the 4 Pharmacokinetics?

Cumulative effects in older adults:

• Inadequate absorption

• Impaired distribution

• Slower metabolism

• Impaired excretion

Describe the effects of aging on drug absorption

• Slower GI motility

• Diminished gastric acid production

• Increased gastric pH

• Frequent use of antacids

• Effects from aging skin and muscles

• Atrophy of skin, muscle, GI mucosa

• Decreased blood flow

How does aging affect drug distribution?

Impaired Distribution of drugs

Less albumin (protein bound to drugs to make more water soluble) produced by liver

Allows more of the drug to be unbound (free) to reach receptor sites and therefore have a greater than expected response.

Diseases decreasing albumin production: Cancer, Diabetes, Liver diseases, surgery, burns, inflammation

Circulatory dysfunction Agn blood thickness viscosity

Change in viscosity and coagulability

Diminished body water

Risk of increased concentration of drugs

How does aging affect metabolism?

Slower Metabolism due to hepatic dysfunction, Hepatic dysfunction doesn't work as well Hep

Functional mass decreases

Increased build-up of drugs making them less effective

Cumulative effects and toxicity

How does aging affect drug excretion?

Impaired Excretion due to renal dysfunction

Decreased size, blood flow, filtration, and creatinine clearance

Diseases decreasing function: Hypertension, Heart Failure, and Diabetes

What are some considerations regarding seniors and drug development?

Pharmaceutical research is frequently focused on younger individuals

Older adults are often excluded from or underrepresented in clinical trials

Results may be inappropriately extrapolated to other populations with negative outcomes. Older Adults might respond different than younger individuals

What is the Beers List?

1991 survey to determine Potentially Inappropriate Drugs (PIMS) for older adults Dr. Mark Beers The Beers List Updated study in 2003 and 2012

Health care professionals treating older adults should have ready access to the Beers List and recognize common classes of medications that can produce problems

What are some major drug classes included in the Beers List?

Antidepressants, Antihypertensives, NSAIDs, Analgesics, Antihistamines, and Muscle Relaxants

Drugs to Avoid with Certain Medical Conditions

Drugs that produce significant anticholinergic effects (black parasympathetics)

Cognitive impairment

Syncope/falls

What should any one taking NSAIDs be aware of?

Anyone taking NSAIDs should be cautioned about the real danger of serious complications. In older adults, there may be no warning signs of pain, and the first symptoms of trouble may be a “silent” bleed may lead to fatal GI hemorrhage

Blood thinning (asymptomatic bleeds in GI tract can be fatal)

What are some other GI problems to be aware of?

Avoid prolonged use (no longer than two weeks) of OTC antacids without medical supervision Constipation can be worsened by anticholinergics and oral antimuscarinics (e.g., oxybutynin, tolterodine) for urinary incontinence Other GI problems include indigestion, heartburn, constipation

What are Drugs to Avoid with Cardiovascular disease?

Studies have indicated increased risk of cardiovascular problems (thrombosis, MI, and stroke) with use of NSAIDs and COX-2 inhibitors

Older adult patients with heart failure should avoid certain calcium-channel blockers (for hypotension with decreased strength of contraction)

What is Polypharmacy?

Excessive use of multiple drugs

How can polypharmacy be combatted?

To combat polypharmacy, medication therapy management (MTM) and comprehensive medication review (CMR) are becoming common practice

What is nonadherence?

Defined as not taking medications as prescribed on a regular basis

What are some pediatric considerations when prescribing medicine?

Decreased body surface area, Decreased body volume, Physiology differs compared to adults, Pediatrics are underrepresented in research of many drugs, Children typically receive lower doses than adults, Drug delivery may be altered for pediatrics, Difficulty swallowing tablets and capsules

What are the Pharmacokinetic differences in pediatric patients?

Absorption: Overall decreased compared to adults due to shorter GI tract and faster gastric emptying rate

Distribution: Higher body water and lower body fat in pediatrics may affect dosage Albumin levels lower in pediatrics

Metabolism: Lower in pediatrics compared to adults

Excretion: Lower in pediatrics compared to adults

What is important to keep in mind regarding NSAIDs?

Patient education should be a main focus with NSAIDs, important for holistic approach to health across the lifespan