Chapter 18 – Older Adults
At any age, there is a risk for harmful drug-drug or drug-nutrient interactions, however, older adults are
particularly vulnerable, and this will only become more prevalent. Older adults take a much larger percentage
of prescription and nonprescription medication than their younger counterparts. Several factors to an increase
in risk for older adults:
- They are likely to be taking more drugs for longer periods to control chronic diseases
- Their drugs are likely to be more toxic
- They respond to drugs with increased variability
- They have less capability of handling drugs efficiently
- Their nutritional status is more likely to be deficient
- They are more likely to make increased errors in self-care because of illness, mental confusion, or lack
of drug information
As a result of these problems, concerned physicians, nutritionists, pharmacists, and nurses are increasingly
working together as a team to provide drug and nutrition education, and therapy on a sounder basis.
Effects of Food on Drug Absorption
The five basic circumstances that contribute to increased absorption of a drug:
1. Dissolving Characteristics: When a drug does not dissolve rapidly after its been taken, the time it
remains in the stomach with food is prolonged. This increased time in the stomach may increase its
effective dissolution and consequent absorption. Other times, it may not dissolve properly because of
either the drug or gastric Ph., and it is excreted, thus decreasing absorption of the drug.
2. Gastric-emptying time: Delayed emptying of food from the stomach can have the effect of doling out
small portions of a drug, creating more optimal saturation rates on the absorption sites in the small
intestine.
3. Nutrients: Some nutrients can promote absorption of certain drugs. For example, high-fat diets increase
absorption of the antifungal drugs, such as griseofulvin. High-fat diets stimulate the secretion of bile
acids, which aid in the absorption of the drug. Vitamin C and Gastric Acid enhances iron absorption.
Grapefruit enhances the absorption of many medications.
4. Blood Flow: Food intake increases splanchnic blood flow carrying any ingested drugs. This direct
circulation to abdominal visceral organs stimulates absorption and results in an increased availability of
the accompanying drugs.
5. Nutritional Status: Nutritional status may also affect the bioavailability of certain drugs in different
ways. For example, the antibiotic chloramphenicol is absorbed more slowly in children with protein-
energy malnutrition, but elimination of the drug is slower in well-nourished children.
Decreased Drug Absorption: Absorption of some drugs is delayed or reduced by the presence of food:
1. Aspirin: Absorption of aspirin is reduced or delayed by food. It should be taken on an empty stomach
with ample water, preferably cold.
2. Tetracycline: Nutritional status may also have an effect on drug absorption. For example, tetracycline
absorption is impaired in malnourished individuals. Absorption of this commonly used antibiotic is also
hindered when it is taken with milk, as well as antacids or iron supplements. This drug combines with
these materials to form a new insoluble compounds that the body cannot absorb, resulting in the loss of
mineral involved, such as calcium or iron.
3. Phenytoin: The presence of protein inhibits absorption of phenytoin. Carbohydrate increases its
absorption, but fat has no effect.
Herb and Drug Interaction
, The FDA does not regulate herbal remedies and dietary supplements, so the purity, potency, and safety of these
products can and do vary. It is likely for herbs and dietary supplements to be contaminated with other herbs,
pesticides, herbicides, and other products during growth, harvesting, preparation, and storage. The reason many
people use herbal remedies and food supplements is based in tradition, as well as in their belief in the market
claims for them being “miracle cures.” They also turn to them because they are considered to be “natural.”
However, it is important to remember that hemlock, nightshade, mistletoe berries, belladonna, and poison ivy
are also “natural.”
*Natural is not synonymous with safe- especially when they combine with medications
Drugs that may Stimulate the Appetite
Appetite Changes: The following drugs may stimulate appetite, weight gain, or both.
1. Antihistamines: Theses drugs can lead to marked increase in appetite and subsequent weight gain.
Cyproheptadine hydrochloride (periactin) is an antihistamine also used an appetite stimulant.
2. Antianxiety Drugs: Some drugs in this classification may lead to hyperphagia, or excessive eating. Some
of these drugs include chlordiazepoxide hydrochloride (Librium), diazepam (Valium), and alprazolam
(Xanax).
3. Tricyclic Antidepressants: These medications, along with most antipsychotic drugs such as amitriptyline
hydrochloride (Elavil), Olanzapine (Zyprexa), chlorpromazine hydrochloride (Thorazine), and clozapine
(Clozaril), may promote appetite and lead to significant weight gain.
4. Insulin: Hypoglycemia can occur in persons with type 1 diabetes if food is not taken immediately after
their insulin injection. If some food is not readily available to counteract the rapid progression of the
unrelieved server hypoglycemia, then coma and death occur. If excess food is consumed, then weight
gain may occur.
5. Steroids: Anabolic steroids, including testosterone, promote nitrogen retention, increased lean body
mass, and subsequent weight gain.
The following drugs may depress appetite:
1. Selective Serotonin Reuptake Inhibitors (SSRIs): This class of antidepressants may cause anorexia and
weight loss; an example is fluoxetine (Prozac).
2. Amphetamine: These drugs act as stimulants to the CNC and have the effect of depressing the desire for
food, thus leading to marked loss of weight. They have been used in the past as appetite-depressant
drugs in the treatment of obesity. Long-term use may lead to addiction, which is why they are rarely
used for this purpose, and may cause growth retardation in children.
3. Alcohol: Abuse of alcohol can lead to loss of appetite, reduced food intake, and malnutrition. The
anorexia, or loss of appetite, can stem from various effects of alcoholism such as gastritis, hepatitis,
cirrhosis, ketosis, pancreatitis, alcoholic brain syndrome, drunkenness, and withdrawal symptoms. The
resulting reduced food intake can then lead to malnutrition, which further complicates the anorexia.
Mineral Depletion
Certain drugs can lead to mineral depletion through induced GI losses or renal excretions:
1. Diuretics: Intentionally used to reduce levels of excess tissue water and sodium, but they may also result
in loss of other minerals, such as potassium, magnesium, and zinc. Potassium deficiency brings
weakness, anorexia, nausea, vomiting, listlessness, apprehension, and sometimes diffuse pain,
drowsiness, stupor, and irrational behavior.
2. Alcohol: Abuse of alcohol can lead to diminished levels of potassium, magnesium, and zinc.
At any age, there is a risk for harmful drug-drug or drug-nutrient interactions, however, older adults are
particularly vulnerable, and this will only become more prevalent. Older adults take a much larger percentage
of prescription and nonprescription medication than their younger counterparts. Several factors to an increase
in risk for older adults:
- They are likely to be taking more drugs for longer periods to control chronic diseases
- Their drugs are likely to be more toxic
- They respond to drugs with increased variability
- They have less capability of handling drugs efficiently
- Their nutritional status is more likely to be deficient
- They are more likely to make increased errors in self-care because of illness, mental confusion, or lack
of drug information
As a result of these problems, concerned physicians, nutritionists, pharmacists, and nurses are increasingly
working together as a team to provide drug and nutrition education, and therapy on a sounder basis.
Effects of Food on Drug Absorption
The five basic circumstances that contribute to increased absorption of a drug:
1. Dissolving Characteristics: When a drug does not dissolve rapidly after its been taken, the time it
remains in the stomach with food is prolonged. This increased time in the stomach may increase its
effective dissolution and consequent absorption. Other times, it may not dissolve properly because of
either the drug or gastric Ph., and it is excreted, thus decreasing absorption of the drug.
2. Gastric-emptying time: Delayed emptying of food from the stomach can have the effect of doling out
small portions of a drug, creating more optimal saturation rates on the absorption sites in the small
intestine.
3. Nutrients: Some nutrients can promote absorption of certain drugs. For example, high-fat diets increase
absorption of the antifungal drugs, such as griseofulvin. High-fat diets stimulate the secretion of bile
acids, which aid in the absorption of the drug. Vitamin C and Gastric Acid enhances iron absorption.
Grapefruit enhances the absorption of many medications.
4. Blood Flow: Food intake increases splanchnic blood flow carrying any ingested drugs. This direct
circulation to abdominal visceral organs stimulates absorption and results in an increased availability of
the accompanying drugs.
5. Nutritional Status: Nutritional status may also affect the bioavailability of certain drugs in different
ways. For example, the antibiotic chloramphenicol is absorbed more slowly in children with protein-
energy malnutrition, but elimination of the drug is slower in well-nourished children.
Decreased Drug Absorption: Absorption of some drugs is delayed or reduced by the presence of food:
1. Aspirin: Absorption of aspirin is reduced or delayed by food. It should be taken on an empty stomach
with ample water, preferably cold.
2. Tetracycline: Nutritional status may also have an effect on drug absorption. For example, tetracycline
absorption is impaired in malnourished individuals. Absorption of this commonly used antibiotic is also
hindered when it is taken with milk, as well as antacids or iron supplements. This drug combines with
these materials to form a new insoluble compounds that the body cannot absorb, resulting in the loss of
mineral involved, such as calcium or iron.
3. Phenytoin: The presence of protein inhibits absorption of phenytoin. Carbohydrate increases its
absorption, but fat has no effect.
Herb and Drug Interaction
, The FDA does not regulate herbal remedies and dietary supplements, so the purity, potency, and safety of these
products can and do vary. It is likely for herbs and dietary supplements to be contaminated with other herbs,
pesticides, herbicides, and other products during growth, harvesting, preparation, and storage. The reason many
people use herbal remedies and food supplements is based in tradition, as well as in their belief in the market
claims for them being “miracle cures.” They also turn to them because they are considered to be “natural.”
However, it is important to remember that hemlock, nightshade, mistletoe berries, belladonna, and poison ivy
are also “natural.”
*Natural is not synonymous with safe- especially when they combine with medications
Drugs that may Stimulate the Appetite
Appetite Changes: The following drugs may stimulate appetite, weight gain, or both.
1. Antihistamines: Theses drugs can lead to marked increase in appetite and subsequent weight gain.
Cyproheptadine hydrochloride (periactin) is an antihistamine also used an appetite stimulant.
2. Antianxiety Drugs: Some drugs in this classification may lead to hyperphagia, or excessive eating. Some
of these drugs include chlordiazepoxide hydrochloride (Librium), diazepam (Valium), and alprazolam
(Xanax).
3. Tricyclic Antidepressants: These medications, along with most antipsychotic drugs such as amitriptyline
hydrochloride (Elavil), Olanzapine (Zyprexa), chlorpromazine hydrochloride (Thorazine), and clozapine
(Clozaril), may promote appetite and lead to significant weight gain.
4. Insulin: Hypoglycemia can occur in persons with type 1 diabetes if food is not taken immediately after
their insulin injection. If some food is not readily available to counteract the rapid progression of the
unrelieved server hypoglycemia, then coma and death occur. If excess food is consumed, then weight
gain may occur.
5. Steroids: Anabolic steroids, including testosterone, promote nitrogen retention, increased lean body
mass, and subsequent weight gain.
The following drugs may depress appetite:
1. Selective Serotonin Reuptake Inhibitors (SSRIs): This class of antidepressants may cause anorexia and
weight loss; an example is fluoxetine (Prozac).
2. Amphetamine: These drugs act as stimulants to the CNC and have the effect of depressing the desire for
food, thus leading to marked loss of weight. They have been used in the past as appetite-depressant
drugs in the treatment of obesity. Long-term use may lead to addiction, which is why they are rarely
used for this purpose, and may cause growth retardation in children.
3. Alcohol: Abuse of alcohol can lead to loss of appetite, reduced food intake, and malnutrition. The
anorexia, or loss of appetite, can stem from various effects of alcoholism such as gastritis, hepatitis,
cirrhosis, ketosis, pancreatitis, alcoholic brain syndrome, drunkenness, and withdrawal symptoms. The
resulting reduced food intake can then lead to malnutrition, which further complicates the anorexia.
Mineral Depletion
Certain drugs can lead to mineral depletion through induced GI losses or renal excretions:
1. Diuretics: Intentionally used to reduce levels of excess tissue water and sodium, but they may also result
in loss of other minerals, such as potassium, magnesium, and zinc. Potassium deficiency brings
weakness, anorexia, nausea, vomiting, listlessness, apprehension, and sometimes diffuse pain,
drowsiness, stupor, and irrational behavior.
2. Alcohol: Abuse of alcohol can lead to diminished levels of potassium, magnesium, and zinc.
