Geriatrics

Question 1

Peculiarities of the old

Answer 1

• More susceptible to chances of drug interactions and ADRs.
• Presence of multiple diseases and nutritional problems.
• Loss of spouse
• Poor patient compliance
• Sluggishness of various body functions.
• Pharmacological changes due to ageing.

Question 2

Factors affecting GI Absorption

Answer 2

• 1) Increase in Gastric pH.
• 2) Reduced GI Motility.
• 3) Reduced blood flow.
• 4) Decrease absorption surface in the GIT.
• 5) Decrease in gastric enzymes.

Question 3

Explain Factor - increase in Gastric pH.

Absorption

Answer 3

-

Question 4

Explain Factor -
Reduced GI Motility
(Absorption)

Answer 4

• Due to Motility disorders associated with Atypical GERD and small intestine dysmotility.
• Drugs become poorly absorbed; thus decrease absorption and bioavailability.
• Patients with GIT motility disorders are most likely to have poorly predictable therapeutic effect.

Question 5

What optimizes consistent absorption?

Answer 5

Ensuring:

• Formulation of drugs
• Timing of administration in relation to meals and the use of other drugs.

Question 6

Explain Factor -

Reduced blood flow (Absorption)

Answer 6

Elders may have reduced blood enterohepatic circulation; thus reducing absorption rate and interfering with Cmax (maximum conc.)

Question 7

Explain Factor -
Decrease absorption surface in GIT
(Absorption)

Answer 7

Elders may have poor gastrointestinal ability, which reduces drug absorption rate.

Question 8

Explain Factor -
Decrease in gastric enzymes
(Absorption)

Answer 8

• Secretion of gastric enzymes are reduced.

-

Question 9

Factors affecting Distribution

Answer 9

• Reduced body weight.
• Reduced lean body mass.
• Increased body fat.
• Reduced total body water.
• Decreased serum albumin (plasma proteins).
• Increased alpha 1-acid glycoprotein.
• Decrease cardiac output/blood flow.

Question 10

Explain Factor -
Reduced lean body mass
(Distribution)

Answer 10

• Increases volume distribution.
• Water soluble drugs have longer half-life.
• Lipid soluble drugs accumulate into fat.

Question 11

Explain Factor -
Reduced total body water
(Distribution)

Answer 11

• Increased plasma conc. of water soluble drugs.
• Lower doses are required
  e. g. Lithium, Digoxin, Ethanol.

Question 12

Discuss Factor -
Decreased serum albumin (plasma proteins)
(Distribution)

Answer 12

• More free drugs.
• Increased unbound fraction of highly protein bound drugs:
  Acidic drugs
  e.g. Warfarin, Phenytoin.

Question 13

Basic drugs such as lidocaine and propranolol bind to…

Answer 13

alpha 1-acid glycoprotein.

Question 14

Factors affecting Metabolism

Answer 14

• Decreased hepatic mass.
• Decreased hepatic blood flow.
• Malnutrition and diseases that affect hepatic function are more common in elderly.
• Idiosyncratic reactions.

Question 15

Discuss Factor -
Decreased hepatic mass
(Metabolism)

Answer 15

• Metabolizing capacity of liver is decreased only for certain drugs such as: Diazepam and Propranolol.
• Greatest changes seen in Phase I reactions: Phase I inactivation reduced by microsomal mixed function oxidases.
• Conjugation reactions aren’t significantly affected.

Question 16

Discuss Factor -
Decreased hepatic blood flow
(Metabolism)

Answer 16

Causes:

• Slower metabolic inactivation of drugs.
• Decreased first pass metabolism of drugs (will have higher than normal conc.) e.g. Antidysrhythmic drugs.