ch9 pharmacology, CAM, and supplements

define pharmacotherapy

use of drugs for the treatment of disease and health maintenance

define pharmacology

study of drugs, properties, and their effects

define pharmacokinetics

 study of drug absorption, distribution, metabolism, and excretion

what are the roles of nutrition therapy in pharmacotherapy? (4)

• nutrition effects drug action

• drug affects nutrition

• “drug-nutrient” interactions

as dietitians we want to prevent

interactions (prevention interaction)

role of the RDN in pharmacotherapy? (5)

• coordination of nutrition therapy with medication

• improve patient outcomes

• maximize nutrition status

• decrease complications of the prescribed medical care

• Legal requirements for accreditation of health care facilities

what do we mean by drug mechanisms

involved the binding of the drug to specific receptors on the cell membrane

the binding of drug to specific receptors on the cell membrane causes what

initiates enzyme reactions

do drugs bind to one receptor?

not all, some can interact with more than one cell receptor

medications cause alterations in enzyme systems either by ___________ or _____________

stimulating or inhibiting them

what is an example of a drug that inhibits?

ACE inhibitor

how does ACE inhibitors work?

the prevent the conversion of angiotensin I to angiotensin II

which prevents angiotensin II from stimulating vasoconstriction and causing BP to rise —→ so we have a DECREASE in BP

what are the possible types of drug administration? (5)

• sublingual or buccal

• topical

• inhalation

• parenteral

• placed directly into target tissues

what does parenteral mean?

refers to injection into the body’s circulatory system through a blood vessel

what are the possible parenteral routes

• subcutaneous (SC)

• intradermal (ID)

• intramuscular (IM)

• intraperitoneal (IP)

• intravenous (IV)

what are the types of absorption mechanisms of drugs (3)

• passive diffusion

• facilitated diffusion

• active transport

what factors effect absorption of drugs? (8)

• solubility and ionization

• excipients (affect dissolution- dissolving)

• time in GI tract area

• pH in GI tract area

• surface area of GI tract area

• chemical properties

• integrities of GI

• circulation of blood

how does solubility and ionization impact drug absorption?

lipid based drugs and nonionized drugs will be absorbed more quickly through membrane

what are excipients?

those substances added to formulations of medications that affect dissolution (ability to dissolve)

examples:

Decrease dissolution: Binders, lubricants, coating agents

Increase dissolution: disintegrants (ingredients that dissolve rapidly in water)

distribution of drugs refers to

movement of the drug throughout the body to its target side

what factors effect distribution of drugs (5)

• affected by circulation

• binding to proteins within the circulation (i.e. albumin)

• physiological features

• capillary permeability

• solubility in water (insoluble is easier to distribute)

• binding of drug to other body tissues

what does biotransformation mean?

drug metabolism

what does biotransformation do?

Resulting in a substance that may be similarly active, inactive (and ready for excretion via urine or bile), or differently active in terms of therapeutic activity or toxicity

what are the major sites of biotransformation?

GI and liver

what reactions occur in biotransformation (metabolism)

oxidation, reduction, hyrolysis

how does biotransformation occur?

through catalyst of enzyme systems

what is the main enzyme system that metabolizes drugs?

cytochrome P450 mixed function oxidases system

what is the cytochrome P450 mixed function oxidases system

a system of enzymes responsible for drug metabolism

how can genetic variation in these enzyme systems impact drug effect

can increase of decrease drug effect

interaction between substrate and enzyme systems can be either ___ or ____

inhibitor or inducer

what is a substrate

a drug that gets broken down by an enzyme

what is an inhibitor

reacts with substrate to compete for receptor site on enzyme

an inhibitor will affect drug effect how?

will increase the effect

because it will compete for the enzyme that metabolizes the drug, so less rug will be metabolized and will remain in the blood

what is an inducer?

stimulates the synthesis of enzyme

inducer will affect drug effects how?

will decrease them

because will increase the amount of enzyme available to metabolize the drug so decrease amounts in the blood quicker

what are therapeutic levels (what does this mean?)

dosing adjusted to accommodate predicted metabolism of the drug

what are common inducers?

• Strong inducers: Carbamazepine, rifampin

• Others: tobacco; brussels sprouts (in vitro)

what are common inhibitors?

• Ciprofloxacin, clarithromycin, fluconazole, gemfibrozil, ticlodipine, fluoxetine

• Others: star fruit (in vitro); Grapefruit

how is an effective dose for a person established?

blood levels are measured

what is the therapeutic window?

The dosage range with therapeutic efficacy

levels above or below the therapeutic window may

not be effective or result in toxicity

drug excretion: how are most drugs excreted?

urinary or biliary excretion

what are other ways that a drug can be excreted that is not urinary or biliary?

lungs, bowel, and breast milk

urinary excretion can occur when?

in all stages of filtration and concentration of the kidneys

what do we mean by alterations in pharmacokinetics

the changes from person to person because no two people will react in the same way to a medication

Age; gender; cardiovascular, hepatic, and renal function; presence of disease or infection; diet; and even genetic differences will affect how an individual will respond to a drug dosage

what factors can alter GI absorption of a drug? (5)

• Simultaneous consumption with food

• Vomiting and diarrhea

• Interruptions in transit time or surface area

• Circulation deficits (decreased blood circulation)

• Competition for carriers

what factors can alter drug distribution? (3)

• Variations in circulation

• Body size and composition

• Any situation altering albumin (most medications are bound to this protein carrier)

what factors can alter drug metabolism? (5)

• Age

• Adequate functions of organs

• Genetic factors

• Gender

• Concurrent use of other medications or supplements

what factors can alter urinary excretion? (4)

• pH of urine has direct effect on the type of drug easily excreted

• Presence of competitor for active transport across renal tubule

• Urinary flow rates or kidney function

• Changes in Creatinine clearance

what are food-drug interactions?

effects of food and nutrition on dissolution, absorption, metabolism, and excretion of medications.

Food-medication interactions can be organized by examining what 3 things?

• Effect of nutrition on the action of the prescribed medication

• Effect of the medication on nutritional status

• Role of nutrition therapy in maximizing the prescribed effect of pharmacotherapy and/or minimizing the side effects

what factors impact drug dissolution (3)

• pH of stomach

• Gastric emptying rate (i.e. prokinetics)

• Disease, injury, or surgery

how can nutrition impact absorption (3)

• increase absorption

• decrease absorption

• chelation

if interaction with food increases absorption of medication, how does it impact drug effect

increases the amount of available drug in blood

if interaction with food decreases drug absorption, how may it impact effect?

therapeutic levels may not be reached (less drug is absorbed)

define chelation

the binding of a nutrient or food component with a drug, makes the drug unabsorbable

how can food impact drug metabolism? (3)

• Food can act as an Inducer for metabolic enzyme systems

• Food can act as an inhibitor for metabolic enzyme systems

• Nutrients can compete for carrier systems

how can food impact drug excretion

Variable urine pH can alter reabsorption of drug

Dietary intake, kidney and respiratory function, acid-base balance, hydration status, and the presence of disease or infection can alter urinary pH

how do warfarin and vit K interact?

warfarin (coumadin) is a anticoagulant that is a competitive inhibitor of clotting factors AND vit K creates clotting factors —> SOOO when taking warfarin and inconsistent intake of vit K —→ impact the effectiveness of dosing (so should consume consistent amounts)

how could drugs impact nutrition status?

Drugs affect nutrient ingestion, digestion, absorption, and metabolism.

how may drugs impact nutrient ingestion?

• having side effects like N/V/D, constipation, increased appetite, decreased appetite impact dietary intake

• having additive effects from taking multiple medications

• medication impact of taste, smell, and saliva production

drugs can impact weight in what ways? (2)

cause weight gain or weight loss

how may drugs effect nutrient absorption?

• speed transit time or gastric emptying

• Have GI effect (N/V/D/C)

• Change acidity

• Block absorption via enzymes, competition, inhibition

how can drugs alter nutrient metabolism

 interfere with macronutrient, vitamin, and mineral metabolism

corticosteroids impact nutrient metabolism how?

increase rate of gluconeogenesis —> result in hyperglycemia and increased nitrogen loss

what kind of drugs (generic) would place a pt at risk of increased nutrient excretion?

any drug that increases urinary output

how may drugs impact nutrient excretion? (2)

• increase urinary output

• affect renal function to reduce reabsorption

how may lasix (a diuretic) impact nutrient excretion?

increase excretion of potassium and thiamin

what populations is at high risk of drug-nutrient interactions? (2)

the elderly and nutrition support

why are elder adults are high risk for drug-nutrient interactions?

• polypharmacy

• usage of both over-the-counter and prescription medications

• physiological changes that occur with aging

• compliance of medications

• inappropriate dosage

what is polypharmacy

administration of excessive drugs at one time or concurrent use of a large number of drugs, which increases the risk of interactions (3 or more)

how does one asses older adults for risk of drug-nutrient interactions?

beers criteria

what is beer’s criteria

The Beers criteria identify the medications most likely to result in adverse effects

General components of these criteria state that if a patient uses more than five drugs, is noncompliant with medication regimens, and has a history of adverse effects, the risk of continued interactions is high

why are nutrition support pts at risk populations for drug-nutrient interactions (and vice versa)

• Tube feedings decrease absorption of some medicines

• Macronutrients may cause chelation of medicines

what are the safe practice reccomendations provided by the American society for enteral and parenteral nutrition regarding medication and enteral feedings (6)

• Do not add medication directly to an enteral feeding.

• Avoid mixing together medications that are intended to be administered through an enteral feeding tube. Additional medications can be given sequentially but not mixed.

• Liquid medication formulations should be used, when available, for administration via enteral feeding tubes.

• When medications are administered via an enteral feeding tube, the tube should be flushed before and after each medication is administered.

• Restart the feeding after administering the medication to avoid compromising nutrition status.

• Consult with a pharmacist for patients receiving medication coadministered with enteral nutrition.

for MNT, what should we be on the lookout for that impact nutritional status

Prescribed drugs, OTC meds, or complementary treatments have the potential to affect nutritional status

nutrition assessment should focus on

factors that could affect absorption, distribution, metabolism, or excretion of drugs

what is the nutrition diagnosis when there is an interaction issue

food-medication interaction

what should int MNT intervention be when there is an interaction?

will center around modification of diet or medication to reduce risk

nutrition assessment walk-through

COMPLEMENTARY AND ALTERNATIVE MEDICINE AND NUTRITIONAL SUPPLEMENTS

Define complementary and alternative medicine (CAM)

is a collective term for complementary medicine, alternative medicine, and integrative health care

what is complementary medicine?

the use of a nonmainstream health practice that is used together with conventional medicine

what is alternative medicine?

unconventional health practices used in place of conventional medicine

what is integrative health care

systems that bring both conventional and complementary health practices together in a coordinated way

what is a dietary supplement (definition)

• a approach (other than tobacco) that is intended to supplement the diet

• contains one or more dietary ingredients (including vitamins, minerals, herbs or other botanicals, amino acids, and other substances) or their constituents

• is intended to be taken by mouth as a pill, capsule, tablet, or liquid

• and is labeled on the front panel as being a dietary supplement

what established the guidelines for supplements?

Dietary Supplement Health and Education Act of 2006 (DSHEA) established the guidelines for regulation by FDA as a subcategory of foods but not as drugs or food additives

based on DSHEA, supplement

• approval?

• safety and efficacy?

• burden of proof for safety?

• Do not need market approval from the FDA

• Do not have to prove safety and efficacy

• Burden of proof for safety relies on the FDA establishing proof rather than the supplement manufacturer

product health claims and dietary supplements (its rules)

can be on the label but must also include: "this claim has not been evaluated by the FDA. This product is not intended to diagnose, treat, cure, or prevent any disease"

role of RDN for dietary supplements? (3)

• Excellent opportunity for team collaboration

• Within RDN scope of practice when providing guidance for dietary supplement use as well as development of a nutrition prescription for repletion or supplementation

• Guidance regarding third-party testing for safety and ingredient assurance

sample micronutrient supplementation prescription

what is the lead federal agency scientific research on complementary and integrative health approaches

national center for complementary and integrative health (NCCIH)

national center for complementary and integrative health (NCCIH)

• mission

• vision

• Mission: Determine, through rigorous scientific investigation, the fundamental science, usefulness, and safety of complementary and integrative health approaches and their roles in improving health and health care

• Vision: Scientific evidence informs decision making by the public, health care professionals, and health policy makers regarding the integrated use of complementary health approaches in a whole person health framework

CAM is mainly used for

pain treatment (49.2%)

what is traditional medicine/healing

All acknowledge and practices, whether explicable or not, used in diagnosing, preventing or eliminating a physical, mental, or social disequilibrium and which rely exclusively on experience and observation handed down from generation to generation, verbally or in writing (WHO, 1976)

what is ayurvedic medicine

An ancient Indian medical system based on ancient writings which rely on a holistic and natural approach to health

what is traditional chinese medicine

Long standing medicine approach that has evolved over thousands of year. Uses various physical and/or psychological approaches to address health problems

what is homeopathy

Developed in Germany over 200 years ago, uses products which come from plants, minerals, or animals. Treatments are generally individualized to each person. Generally, uses clinical signs and symptoms which are different from conventional medicine

what is naturopathy

System developed in Europe during the 19th century which uses a variety of different treatment approaches, such as, stress reduction, exercise therapy, practitioner-guided detoxification, psychotherapy and counseling to take a holistic approach to medicine

nutritional approaches include what 4 categories?

• Herbs: plants, parts of plants

• Vitamins/minerals: extracted vits/minerals

• Probiotics: live microorganisms ingested to promote health

• Dietary supplements: dietary substances taken by mouth to promote health