alcohol. The disulfiram reaction manifests
nutritional status. Some modification in
itself by headaches, nausea, vomiting, chest
interactions could increase or decrease drug
action and/or contribute to dietary deficiencies
associations will minimize or avoid such
is of particular importance in the management
of patients receiving medications. The chronic
use of drugs requires close monitoring of
Drug-Nutrient Interactions of Clinical Relevance José A. Morais, MD, FRCPC, Assistant Professor of Medicine, McGill University Table 1: Mechanisms of Drug-Nutrient Interactions Division of Geriatric Medicine, McGill University Health Centre
prolonged use of medications for the treatmentof chronic conditions and in patients with aborderline nutritional status, e.g. frail elderly
persons and patients with inflammatory bowel
Introduction
vitamin D. The metabolism of vitamin D in the
reduced9, contributing to a higher free plasma
May induce vitamin or mineral deficiencies
disease. Polypharmacy is also recognized as
liver is altered by the anticonvulsant phenytoin,
drug concentration of drugs that are highly
being a risk factor for nutrient depletion and is
developed to treat many medical conditions
leading to decreased calcium absorption and
bound to plasma proteins (>90%): lithium,
often seen in the elderly14. Table 2 illustrates
and to improve patients’ quality of life.
osteomalacia3. Warfarin, an oral anticoagulant
digoxin, valproate, phenytoin, warfarin, NSAIDS
clinically relevant drug-nutrient interactions.
Historically, these active ingredients were
that is a vitamin K antagonist, contributes to
and ASA . This physiological change allows
The choice of the drugs was elicited by the
osteoporosis due to the lack of vitamin K
more of the drug to diffuse out of the vascular
Dietary habits or nutritional deficiencies may alter drug action or toxicity
occurring foods1; some of them are still being
stimulation on new bone formation4.
compartment and to reach the drug receptor
drug-nutrient interactions seen in clinical
sold by the growing market of health-food
Acetylsalicylic acid (ASA) overuse is associated
practice, especially among elderly persons.
stores. Not surprisingly, drugs share the same
with folic acid deficiency, as is methrotrexate by
Nutritional status may alter drug distribution & metabolism
concentration, the plasma clearance is also
inhibition of the dihydrofolate reductase
accelerated with decreased therapeutic effect
enzyme. Examples of increased nutrient losses
interactions responsible for adverse drug
are potassium, magnesium and zinc depletion
borderline high therapeutic concentrations
reactions, known as drug-nutrient interactions.
by diuretics, increased renal calcium excretion
biotransformation reactions in the liver are
because of severe anorexia with or without
The interactions between drugs and nutrients
induced by glucocorticoids and iron losses in
reduced with malnutrition, especially those
nausea and vomiting. This condition is called
occur in both directions, i.e., drugs may alter
the gastrointestinal tract by NSAIDs.
involving phase II reactions by cytochrome
“digitalis cachexia”. The centrally mediated
Table 2: Examples of Clinical Relevant Drug-Nutrient Interactions
the nutritional status and dietary habits, or
P450 isoenzymes10. Medications that are
effect of SSRIs on appetite suppression is also
nutritional deficiencies may alter drug action or
Effects of Diet on Drug Bioavailability
eliminated by hepatic metabolism will have
Mechanism Nutrient Affected
toxicity (Table 1). The knowledge of these
their half-lives increased with higher risks of
malabsorption can be a consequence of the
interactions may help health professionals
toxicity. This is the case with many drugs,
chronic use of colchicine to treat gout because
obtain the maximum effect of a drug and avoid
gastrointestinal tract. Absorption can be
including TAD, neuroleptics, antiarrythmics, etc.
this drug can create a structural defect in the
unnecessary side effects that would diminish
delayed by the effect of the meal in slowing
The opposite effect of a high protein content
intestinal mucosa. As already stated, specific
and severe mineral depletion is seen with
bioavailability. While food usually reduces or
isoenzymes, as is the effect of vegetables of the
diuretics for potassium, sodium, magnesium,
Drugs and General Nutritional Status
delays drug absorption, some drugs’ absorption
Brassica family (cabbage, brussels sprouts) will
Drugs may alter nutritional status because
is promoted with food. This is the case with
result in a decreased therapeutic effect of many
thiazides). The chronic use of NSAIDs or ASA
they can increase or decrease food intake.
medications. Recently, the inhibition of the
to treat arthritis is responsible for iron
Drugs, such as neuroleptics, benzodiazepines,
hydrochlorothiazide and metoprolol. The meal
deficiency anemia, induced by blood loss in the
tricyclic antidepressants (TAD), can directly
content also has an effect on absorption, as
attracted attention because of the increased
gastrointestinal tract. Specific folate deficiency
stimulate the appetite centre in the central
with the once-a-day preparation of theophylline
therapeutic effect seen with most calcium
nervous system leading to weight gain, whereas
that is increased by a high-fat meal5. The
channel antagonists (felodipine, nifedipine,
opposite effect of a high-fat meal is seen for
serotonin-reuptake inhibitors (SSRIs) do the
zidovudine, an antiretroviral agent. A high-
concentration of other drugs metabolized by
opposite2. Weight gain has been observed with
protein meal will also diminish the absorption
hypercholesterolemia through binding of bile
sulfonylurea drugs used to treat diabetes
cholesterol-lowering agents of the statins
mellitus (e.g., glyburide). This weight gain is a
acids for absorption6. Bioavailability can be
employed to control seizure disorders can alter
result of increased insulin secretion by the
family, cisapride, midazolam, triazolam and
affected by the fiber content of the meal that
pancreas. Appetite alterations can also be
cyclosporin11.
binds to the drug and decreases its absorption,
mechanisms, including inhibition of hepatic
SSRIs: Selective serotonin reuptake inhibitors, e.g., fluoxetine, sertraline, fluoxamine
NSAIDs: Nonsteroidal antiinflammatory drugs, e.g., ibuprofen, indomethacin, naproxen
changes in taste perception, as in the case of
Incompatibility of Drugs and Nutrients
osteomalacia. The effect of anticonvulsants on
lithium, metronidazole and metformin. Any
mechanism that decreases the absorption of
bone density can be affected by calcium and
drug that is responsible for the appearance of
drugs is chelation, which consists of the
interaction with clear detrimental effects due to
gastrointestinal symptoms will contribute to
vitamin D supplements. Glucocorticoids are
incompatibility of certain drugs and nutrients12.
The Whitehall-Robins Report is a Whitehall-Robins publication that focuses on current issues on the role of vitamins
decreased appetite and induce protein-energy
drugs with systemic manifestations that are
insoluble non-absorbable product. This is the
This is the case for the irreversible monoamine
and minerals in health promotion and disease prevention. Complimentary copies are distributed to Canadian health
malnutrition. Examples of this are dyspepsia,
employed in many serious medical conditions.
care professionals active or with a special interest in nutrition. Each issue is written and/or reviewed by independent
caused by nonsteroidal antiinflammatory drugs
Unfortunately, they also contribute to an array
tranylcypromine) with food containing tyramine
health care professionals with expertise in the chosen topic.
(NSAIDs), constipation induced by narcotics
and nausea from theophylline or digitalis
electrolyte abnormalities (hypernatremia and
effectiveness is compromised when concurrently
If you have any comments about the Whitehall-Robins
ingested with calcium supplements or dairy
accumulates in the body when inhibitors are
nitrogen balance, responsible for loss of lean
Report or would like to be added to the mailing list,
products7.
given to treat depressive mood disorders.
Drugs and Mineral and Vitamin Deficiencies
It reaches toxic levels that are responsible for
prevented in part with diet counseling and use
Nutritional Status Affecting Drug Metabolism
headaches, nausea, vomiting, palpitations,
The Editor: The Whitehall-Robins Report,
2000-February. May be reproduced without
5975 Whittle Road, Mississauga, ON L4Z 3M6
permission provided source is recognized.
absorption, by altering their metabolism or by
alter drug distribution and metabolism. Drug
cerebrovascular accidents. Similar reactions
Conclusions
distribution is affected because protein-energy
are observed with isoniazid-treated patients
REFERENCES 1. Camp J. Magic, Myth and Medicine. New York, Taplinger Publishing Co., 1974. 2. Stock MJ. Sibutramine: a review of the pharmacology of a novel anti-obesity agent. Int J Obes Relat Metab Disord 1997;21(suppl):S25-
medications that increase stomach pH will
malnutrition is associated with low body fat
29. 3. Ray JG, Adachi JR. Anticonvulsants and bone disease: a systematic overview of their association and possible preventive strategies. Can J Clin Pharmacol 1998;4:217-223. 4. Heaney RP. Nutritional factors in osteoporosis. Annu
decrease iron absorption by decreasing the rate
depots and loss of lean body mass8. This
histamine such as sardinella, skipjack or tuna13.
Rev Nutr 1993;13:287-316. 5. Karim A, Burns T, Janky D, Hurwitz A. Food induced changes in theophylline absorption from controlled release formulations. II. Importance of meal composition and dosing time relative to meal intake
of conversion of ferric iron to its absorbable
implies that the volume of distribution for
The disulfiram-like reaction is another example
in assessing changes in absorption. Clin Pharmcol Ther 1985;38:642-647. 6. Goldin BR, Goldman P. The metabolism of L-dopa: the role of the intestinal microflora. Fed Proc 1973;32:798. 7. The Medical Letter. Ethididronate for postmenopausal osteoporosis. Vol. 14, No. 19 (M.L. 833), January 11,1991. 8. Shizgal HM. Nutritional assessment with body composition measurements. JPEN 1987;11(suppl):S42-47. 9. Ashton M, Bolme P, Zerihum G, Holmberg K,
ferrous form. Mineral oil, if taken in the
water-soluble drugs (digitalis, cimetidine) is
of this category of interactions observed when
Paalzow LK. Disposition of salicylic acid in malnourished Ethiopian children after single oral dose. Clin Pharmacokinet 1993;25(suppl):S483-494. 10. Mandl J, Banhegyi G, Kalapos MP, Garzo T. Increased oxidation and decreased
postprandial period will reduce absorption of
reduced in malnutrition with increased risks of
metronidazole, nitrofurantoin, griseofulvin or
conjugation of drugs in the liver caused by starvation. Altered metabolism of certain aromatic compounds and acetone. Chemico-Biological Interactions 1995;96:87-101. 11. Bailey DG, Malcom J, Arnold O, Spence JD. Grapefruit juice-
fat-soluble vitamins, including carotenes and
side effects. Serum binding proteins are also
chlorpropamide are taken in association with
drug interactions. Brit J Clin Pharmacol 1998;46:101-110. 12. Roe DA. Interactions between drugs and nutrients. Med Clin N Amer 1979;63:985-1007. 13. Uragoda CG. Histamine poisoning in tuberculous patients after ingestion of tuna fish. Ann Rev Resp Dis 1980;121:157-160. 14. Steward RB, Cooper JW. Polypharmacy in the aged. Drugs & Aging 1994;9:73-80.
Contains 50% recycled paper including 20% post-consumer fibre
alcohol. The disulfiram reaction manifests
nutritional status. Some modification in
itself by headaches, nausea, vomiting, chest
interactions could increase or decrease drug
action and/or contribute to dietary deficiencies
associations will minimize or avoid such
is of particular importance in the management
of patients receiving medications. The chronic
use of drugs requires close monitoring of
Drug-Nutrient Interactions of Clinical Relevance José A. Morais, MD, FRCPC, Assistant Professor of Medicine, McGill University Table 1: Mechanisms of Drug-Nutrient Interactions Division of Geriatric Medicine, McGill University Health Centre
prolonged use of medications for the treatmentof chronic conditions and in patients with aborderline nutritional status, e.g. frail elderly
persons and patients with inflammatory bowel
Introduction
vitamin D. The metabolism of vitamin D in the
reduced9, contributing to a higher free plasma
May induce vitamin or mineral deficiencies
disease. Polypharmacy is also recognized as
liver is altered by the anticonvulsant phenytoin,
drug concentration of drugs that are highly
being a risk factor for nutrient depletion and is
developed to treat many medical conditions
leading to decreased calcium absorption and
bound to plasma proteins (>90%): lithium,
often seen in the elderly14. Table 2 illustrates
and to improve patients’ quality of life.
osteomalacia3. Warfarin, an oral anticoagulant
digoxin, valproate, phenytoin, warfarin, NSAIDS
clinically relevant drug-nutrient interactions.
Historically, these active ingredients were
that is a vitamin K antagonist, contributes to
and ASA . This physiological change allows
The choice of the drugs was elicited by the
osteoporosis due to the lack of vitamin K
more of the drug to diffuse out of the vascular
Dietary habits or nutritional deficiencies may alter drug action or toxicity
occurring foods1; some of them are still being
stimulation on new bone formation4.
compartment and to reach the drug receptor
drug-nutrient interactions seen in clinical
sold by the growing market of health-food
Acetylsalicylic acid (ASA) overuse is associated
practice, especially among elderly persons.
stores. Not surprisingly, drugs share the same
with folic acid deficiency, as is methrotrexate by
Nutritional status may alter drug distribution & metabolism
concentration, the plasma clearance is also
inhibition of the dihydrofolate reductase
accelerated with decreased therapeutic effect
enzyme. Examples of increased nutrient losses
interactions responsible for adverse drug
are potassium, magnesium and zinc depletion
borderline high therapeutic concentrations
reactions, known as drug-nutrient interactions.
by diuretics, increased renal calcium excretion
biotransformation reactions in the liver are
because of severe anorexia with or without
The interactions between drugs and nutrients
induced by glucocorticoids and iron losses in
reduced with malnutrition, especially those
nausea and vomiting. This condition is called
occur in both directions, i.e., drugs may alter
the gastrointestinal tract by NSAIDs.
involving phase II reactions by cytochrome
“digitalis cachexia”. The centrally mediated
Table 2: Examples of Clinical Relevant Drug-Nutrient Interactions
the nutritional status and dietary habits, or
P450 isoenzymes10. Medications that are
effect of SSRIs on appetite suppression is also
nutritional deficiencies may alter drug action or
Effects of Diet on Drug Bioavailability
eliminated by hepatic metabolism will have
Mechanism Nutrient Affected
toxicity (Table 1). The knowledge of these
their half-lives increased with higher risks of
malabsorption can be a consequence of the
interactions may help health professionals
toxicity. This is the case with many drugs,
chronic use of colchicine to treat gout because
obtain the maximum effect of a drug and avoid
gastrointestinal tract. Absorption can be
including TAD, neuroleptics, antiarrythmics, etc.
this drug can create a structural defect in the
unnecessary side effects that would diminish
delayed by the effect of the meal in slowing
The opposite effect of a high protein content
intestinal mucosa. As already stated, specific
and severe mineral depletion is seen with
bioavailability. While food usually reduces or
isoenzymes, as is the effect of vegetables of the
diuretics for potassium, sodium, magnesium,
Drugs and General Nutritional Status
delays drug absorption, some drugs’ absorption
Brassica family (cabbage, brussels sprouts) will
Drugs may alter nutritional status because
is promoted with food. This is the case with
result in a decreased therapeutic effect of many
thiazides). The chronic use of NSAIDs or ASA
they can increase or decrease food intake.
medications. Recently, the inhibition of the
to treat arthritis is responsible for iron
Drugs, such as neuroleptics, benzodiazepines,
hydrochlorothiazide and metoprolol. The meal
deficiency anemia, induced by blood loss in the
tricyclic antidepressants (TAD), can directly
content also has an effect on absorption, as
attracted attention because of the increased
gastrointestinal tract. Specific folate deficiency
stimulate the appetite centre in the central
with the once-a-day preparation of theophylline
therapeutic effect seen with most calcium
nervous system leading to weight gain, whereas
that is increased by a high-fat meal5. The
channel antagonists (felodipine, nifedipine,
opposite effect of a high-fat meal is seen for
serotonin-reuptake inhibitors (SSRIs) do the
zidovudine, an antiretroviral agent. A high-
concentration of other drugs metabolized by
opposite2. Weight gain has been observed with
protein meal will also diminish the absorption
hypercholesterolemia through binding of bile
sulfonylurea drugs used to treat diabetes
cholesterol-lowering agents of the statins
mellitus (e.g., glyburide). This weight gain is a
acids for absorption6. Bioavailability can be
employed to control seizure disorders can alter
result of increased insulin secretion by the
family, cisapride, midazolam, triazolam and
affected by the fiber content of the meal that
pancreas. Appetite alterations can also be
cyclosporin11.
binds to the drug and decreases its absorption,
mechanisms, including inhibition of hepatic
SSRIs: Selective serotonin reuptake inhibitors, e.g., fluoxetine, sertraline, fluoxamine
NSAIDs: Nonsteroidal antiinflammatory drugs, e.g., ibuprofen, indomethacin, naproxen
changes in taste perception, as in the case of
Incompatibility of Drugs and Nutrients
osteomalacia. The effect of anticonvulsants on
lithium, metronidazole and metformin. Any
mechanism that decreases the absorption of
bone density can be affected by calcium and
drug that is responsible for the appearance of
drugs is chelation, which consists of the
interaction with clear detrimental effects due to
gastrointestinal symptoms will contribute to
vitamin D supplements. Glucocorticoids are
incompatibility of certain drugs and nutrients12.
The Whitehall-Robins Report is a Whitehall-Robins publication that focuses on current issues on the role of vitamins
decreased appetite and induce protein-energy
drugs with systemic manifestations that are
insoluble non-absorbable product. This is the
This is the case for the irreversible monoamine
and minerals in health promotion and disease prevention. Complimentary copies are distributed to Canadian health
malnutrition. Examples of this are dyspepsia,
employed in many serious medical conditions.
care professionals active or with a special interest in nutrition. Each issue is written and/or reviewed by independent
caused by nonsteroidal antiinflammatory drugs
Unfortunately, they also contribute to an array
tranylcypromine) with food containing tyramine
health care professionals with expertise in the chosen topic.
(NSAIDs), constipation induced by narcotics
and nausea from theophylline or digitalis
electrolyte abnormalities (hypernatremia and
effectiveness is compromised when concurrently
If you have any comments about the Whitehall-Robins
ingested with calcium supplements or dairy
accumulates in the body when inhibitors are
nitrogen balance, responsible for loss of lean
Report or would like to be added to the mailing list,
products7.
given to treat depressive mood disorders.
Drugs and Mineral and Vitamin Deficiencies
It reaches toxic levels that are responsible for
prevented in part with diet counseling and use
Nutritional Status Affecting Drug Metabolism
headaches, nausea, vomiting, palpitations,
The Editor: The Whitehall-Robins Report,
2000-February. May be reproduced without
5975 Whittle Road, Mississauga, ON L4Z 3M6
permission provided source is recognized.
absorption, by altering their metabolism or by
alter drug distribution and metabolism. Drug
cerebrovascular accidents. Similar reactions
Conclusions
distribution is affected because protein-energy
are observed with isoniazid-treated patients
REFERENCES 1. Camp J. Magic, Myth and Medicine. New York, Taplinger Publishing Co., 1974. 2. Stock MJ. Sibutramine: a review of the pharmacology of a novel anti-obesity agent. Int J Obes Relat Metab Disord 1997;21(suppl):S25-
medications that increase stomach pH will
malnutrition is associated with low body fat
29. 3. Ray JG, Adachi JR. Anticonvulsants and bone disease: a systematic overview of their association and possible preventive strategies. Can J Clin Pharmacol 1998;4:217-223. 4. Heaney RP. Nutritional factors in osteoporosis. Annu
decrease iron absorption by decreasing the rate
depots and loss of lean body mass8. This
histamine such as sardinella, skipjack or tuna13.
Rev Nutr 1993;13:287-316. 5. Karim A, Burns T, Janky D, Hurwitz A. Food induced changes in theophylline absorption from controlled release formulations. II. Importance of meal composition and dosing time relative to meal intake
of conversion of ferric iron to its absorbable
implies that the volume of distribution for
The disulfiram-like reaction is another example
in assessing changes in absorption. Clin Pharmcol Ther 1985;38:642-647. 6. Goldin BR, Goldman P. The metabolism of L-dopa: the role of the intestinal microflora. Fed Proc 1973;32:798. 7. The Medical Letter. Ethididronate for postmenopausal osteoporosis. Vol. 14, No. 19 (M.L. 833), January 11,1991. 8. Shizgal HM. Nutritional assessment with body composition measurements. JPEN 1987;11(suppl):S42-47. 9. Ashton M, Bolme P, Zerihum G, Holmberg K,
ferrous form. Mineral oil, if taken in the
water-soluble drugs (digitalis, cimetidine) is
of this category of interactions observed when
Paalzow LK. Disposition of salicylic acid in malnourished Ethiopian children after single oral dose. Clin Pharmacokinet 1993;25(suppl):S483-494. 10. Mandl J, Banhegyi G, Kalapos MP, Garzo T. Increased oxidation and decreased
postprandial period will reduce absorption of
reduced in malnutrition with increased risks of
metronidazole, nitrofurantoin, griseofulvin or
conjugation of drugs in the liver caused by starvation. Altered metabolism of certain aromatic compounds and acetone. Chemico-Biological Interactions 1995;96:87-101. 11. Bailey DG, Malcom J, Arnold O, Spence JD. Grapefruit juice-
fat-soluble vitamins, including carotenes and
side effects. Serum binding proteins are also
chlorpropamide are taken in association with
drug interactions. Brit J Clin Pharmacol 1998;46:101-110. 12. Roe DA. Interactions between drugs and nutrients. Med Clin N Amer 1979;63:985-1007. 13. Uragoda CG. Histamine poisoning in tuberculous patients after ingestion of tuna fish. Ann Rev Resp Dis 1980;121:157-160. 14. Steward RB, Cooper JW. Polypharmacy in the aged. Drugs & Aging 1994;9:73-80.
Contains 50% recycled paper including 20% post-consumer fibre
Management of Severe Agitation Key Points 1. The management of the severely agitated or violent patient embraces psychological, physical and pharmacological approaches. 2. Psychological methods focus on controlling the environment through the establishment of communication and trust. 3. Physical measures involve show of force and physical restraint. Physical restrain
(Due date: 6:00pm, October 4, 2013 (Friday))1. Digoxin is used in the treatment of heat disease. In the following table, y representsthe amount of digoxin in the bloodstream and t represents the time in days after taking asingle dose. The initial dosage is 0.5 mg. (i) Formulate a discrete model for the change in concentration per day being proportionalto the amount of digoxin present. Test