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Nutrition two > Nutritional Pharmacology > Flashcards

Nutritional Pharmacology Flashcards

1
Q

What is meant by the pharmacodynamics of a drug , and what can affect this ?

A

‘ How drugs interact with the body to exert their effects ‘ Mode of action
- advancing age
- genetic mutation
- malnutrition (drugs need plasma proteins to bind to . Unbound fractions of medications may create toxicity
- medical conditions

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2
Q

What are 4 common long term side effects of drugs with examples?

A

1) nutrient deficiencies eg metformin and B12
2) metabolic effects - omeprazole and hypomagnesaemia
3) dependence ie diazepam
4) peptic ulcers - NSAIDS
5)osteoporosis - corticosteroids

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3
Q

Explain drug metabolism with phases

A

Drug metabolism is the process by which drugs are changed from a lipid soluble to a water soluble form suitable for excretion

Phase 1- drug is chemically altered to make it suitable for phase 2 reactions or to be excreted using the cytochrome p450 enzymes

Phase 2- molecules from phase 1 are conjugated to a more water soluble product and aid excretion

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4
Q

What is drug excretion and what are the main routes?

A

Drug excretion is the process by which drugs and their metabolites are removed from the body
Main routes: urine, faeces
Minor: sweat, saliva, tears
Renal excretion is the normal route for the elimination of small water soluble molecules. Renal dysfunction = effects rate at which drug is cleared from the body

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5
Q

How and why do some drugs have prolonged excretion times ?

A

Some drugs may be re absorbed and re enter the portal vein- ‘entero- hepatic circulation . This prolongs excretion times and effects for some drugs that need to exert a longer effect eg OCP and NSAIDS

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6
Q

What is absorption? Discuss the factors that effect the absorption of a drug

A

To exert its action or toxicity internally, a drug must first enter the body and be absorbed into the blood stream

Body related factors :
1) gastro- intestinal motility eg diarrhoea increases motility and decreases absorption of OCP
2) malabsorption states eg coeliac, SIBO
3) presence of other substances eg iron absorption is reduced alongside milk and levothyroxine absorption is decreased with calcium

Medicine related:
1) lipid soluble and small molecule drugs have a greater absorption
2) Acidic drugs absorb quicker in an acidic environment eg stomach
3) liquid will absorb quicker than a solid tablet - good for people with digestive difficulty

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7
Q

Name 4 things that can affect the distribution of a drug to body tissues

A

1) binding to plasma proteins affects active concentration of blood. Drugs bind to proteins to travel around the system, only unbound particles go through the gut wall to general circulation. There is only a certain amount of plasma proteins for drugs to bind to
2) binding to other tissues- tetracycline binds to calcium in bones and teeth - infant staining on teeth
3) Accumulation in lipids eg general anaesthetics
4) natural barriers to distribution eg blood brain barrier is highly effective- difficult to get drugs to the brain . Placental barrier

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8
Q

What Is the first pass hepatic metabolism and how does it impact the concentration of drugs in the body?

A

Process by which oral drugs are absorbed via the GIT and taken via the portal vein to the liver to be metabolised
This means drug concentrations can be reduced by the time they reach systemic circulation.
- if a drug is extensively metabolised , less drug reaches the bloodstream, it cannot exert its effect and May need to be alternatively administered eg nitro glycerine spray (angina)

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9
Q

Describe 4 routes of administration which directly influence the bioavailability of a drug

A

1) oral - absorption mainly via SI
2) sublingual / buccal- bypasses hepatic metabolism eg glyceryl trinitrate spray
3) Topical - local effect creams, patches , eye drops . Systemic effect- inhalation
4) Parenteral - intravenous subcutaneous eg insulin . Intramuscular- epi pen

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10
Q

What is meant by the ‘bioavailability’ of a drug ?

A

The proportion of drug that can reach the bloodstream and is available for distribution to its target site of action

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11
Q

How is a medicine defined ?

A

A medicine is any substance or combination of substances which may be used in or administered to human beings with a view to restoring , correcting or modifying physiological functions by exerting a pharmacological , immunological or metabolic action or to making a medical diagnosis

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12
Q

What is meant by pharmacological ?

A

The effect that the drug has on specific functions of the body . Eg statins are capable of inhibiting cholesterol synthesis

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13
Q

What are the drug regulatory restrictions ?

A
  • intended mode of action- all drugs must have a regulatory licence
  • how they are supplied =
    GSL (general sales list)
    PO (pharmacy only )
    POM (prescription only medicine )
    Controlled medicines (more addictive - require extra controls)
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14
Q

Which common OTC drugs can contribute to significant side effects and drug/ nutrient interactions?

A

Analgesics, laxatives, PPIs, cough mixture, anti histamine, decongestants

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15
Q

What do all drugs contain ? Give an example

A

1) active ingredient: part of drug intended to deliver mode of action and is responsible for side effects
2) inactive ingredients: alter the physical properties of the drug - fillers, colouring agents , lactose, preservatives, E numbers - can still cause side effects and trigger allergic reactions / intolerances
Aspirin - active ingredient is salyclic acid . Inactive = cornstarch , cellulose (billers, colouring )

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16
Q

Discuss the interactions between drugs and alcohol

A
  • alcohol can inhibit a drugs metabolism by competing with the drug for the same set of metabolising enzymes
  • this can diminish the effect of the drug and decrease its availability
  • alcohol can magnify the inhibitory effects of sedative and narcotic drugs at their site of action in the brain (codeine, morphine)
  • alcohol can also force certain slow release depot injections out of their depot storage in muscle - can result in overdose
  • some drugs effect the metabolism of alcohol - altering intoxication and adverse effects . Eg cimetidine (reduces stomach acid) inhibits the enzyme needed to break down alcohol
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17
Q

What is an NTI drug?

A

Narrow therapeutic index-

meaning that relatively small deviations from the proper dose can cause a clinically meaningful shift in pharmacological effects when administered to a patient.

(drugs with small differences between their therapeutic and toxic doses,)

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18
Q

Discuss 5 side effects of PPIs

A

1) bone fractures ( decrease calcium absorption due to hypochlorhydria leading to decreased bone mineral density)
2) Hypomagnesaemia and B12 deficiency- HCL is reduced by 90-95% , digestion is impaired , bile and digestive enzymes are not released, fats and carbs are not digested , leading to reduced bioavailability of many nutrients
3) bacterial enteric infections eg clostridium difficile and SIBO. HCL works as an anti microbial . If not working effectively bacterial overgrowth can happen in small intestine .
4) rebound acid hyper-secretion (when ppi is stopped) and heartburn
5) kidney disease
6) Headache
7) GI disturbances

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19
Q

What drug/ nutrient interactions may happen with warfarin?

A

1) large amounts of green vegetables- broccoli, spinach, cabbage, Brussels sprouts seem to reduce the effects of warfarin
- indoles increase the metabolism of warfarin
- vitamin K is a cofactor for the four clotting factors and can antagonise warfarin

2) High doses of vitamin E can inhibit platelet aggregation , and may cause an additive effect alongside warfarin- hemorrhage risk

3) Pomegranate juice can inhibit the CYP450 enzyme that metabolises warfarin, increasing the INR- measure of how long it takes blood to clot

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20
Q

Why does grapefruit interact with a number of medications?

A

Grapefruit alters the pharmacokinetics of a number of drugs, leading to elevation of their serum concentration
- it selectively inhibits the CYP3A4 enzyme in the intestinal wall but not the liver, increasing the bioavailability of drugs that have a high first pass metabolism.
- CYP3A4 enzyme is involved in the metabolism of over 50% of all drugs
- these drugs include digoxin and statins
- pomegranate has a similar effect

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21
Q

What drug interactions might happen with Ginkgo?

A
  • should be avoided with any anti platelet and anticoagulant medication . Needs to be stopped 1 week before surgery as small potential for increased bleeding risk
  • should be monitored with benzodiazepines, anti-epileptic, anti- psychotic, diabetic, hiv meds, omeprezole and talinolol due to possible CYP induction
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22
Q

How may garlic interact with some drugs?

A
  • theoretically, it could interact with anti - platelet and anti- coagulant drugs . However research has shown 4g/day to have little effect on warfarin stabilised patients
  • interspersed throughout the day is generally ok but high dietary and supplements could allow for interactions

-!interactions have been reported with some blood pressure and cholesterol drugs eg atorvastatin and captopril

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23
Q

How can Soy interact with some drugs?

A
  • soy may decrease absorption of levothyroxine
  • may interfere with oestrogen blocking drugs such as tamoxifen due to isoflavone content ( both positive and negative effects observed)
  • may reduce warfarin effect
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24
Q

Dairy might interact with which drugs?

A
  • dairy can bind to bisphosphonates
  • can decrease absorption of levothyroxine, take four hours apart
  • calcium can bind to antibiotics like tetracycline and quinolone, reducing absorption
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25
Q

The OCP can deplete which nutrients and why?

A

B1- reduced activity of the thiamine dependent enzyme
Vitamin A- reduced liver storage
B12- reduced B12 protein binding
Folate, magnesium, B6, B2, C, zinc
(Reduced absorption, increased excretion , increased requirement)

26
Q

What nutrient do statins block and why? What signs should you watch out for?

A

Statins block the synthesis of mevalonic acid , which is the precursor for both cholesterol and Coenzyme Q10.
Watch out for muscle pain and fatigue

27
Q

Which nutrients do steroids deplete and why?

A

Calcium, vitamin d, chromium, folic acid, magnesium, potassium, zinc
Due to increase in urinary excretion and losses from bone tissue

28
Q

Which nutrients might antacids deplete and why?

A

Calcium, iron, chromium and folate
Increased gastric pH may reduce solubility and absorption.
Aluminium is found in a lot of antacids and can bind to calcium to prevent absorption

29
Q

Which nutrients to antibiotics deplete and why?

A

Biotin, B5, B6, B2, B1, B12, K
Destroyed intestinal micro flora may lead to decreased production of various B vitamins and vitamin K

30
Q

What is the plant source of aspirin, what are the differences in effects of both ?

A
  • Aspirin is derived from willow bark (salix alba), which contains salicin. This does not convert to salicylic acid ( a gastric irritant) until it reaches the blood stream and tissues. Therefore it naturally reduces inflammation and pain without any GI side effects as aspirin does.
  • ## Aspirin was synthetically developed from salicylic acid and can cause gastriointestinal bleeding, peptic ulceration and hypersensitivity
31
Q

When drugs are derived from plant sources why do they differ in effect from the plant?

A
  • When pharmaceuticals are developed they ignore the plants benefit as a ‘whole unit’ which relies on all of its constituent parts and all its active components which influence each other to contribute to healing potential and decrease side effects.
  • Companies only extract what they think is important and process it to a marketable potent drug
32
Q

What is meant by the pharmacokinetics of a drug?

A
  • The study of the movement of drugs within the body, the timed movement of any drug going into, through and out of the body.
  • Includes 4 key processes- Absorption, distribution, metabolism and excretion
33
Q

What is meant by the distribution of a drug?

A

Once in the bloodstream, the drug can now be distributed to its target site (normally a receptor) to exert its action

34
Q

What is meant by the metabolism of a drug?

A

Once the drug and the receptor have reacted , the drug returns to the bloodstream and progresses to the liver to be metabolised and then eliminated from the body- the structure of the drug is reduced or changed

35
Q

What is one long term side effect of taking cortico steroids?

A

Corticosteroids can lead to a faster bone turnover and a lower absorption of calcium which can lead to osteoporosis

36
Q

What are some side effects of codeine?

A
  • Can slow down the movement of the GIT and digestion, creating nausea and constipation
  • Opiate analgesics can cause a dependence with long term use
37
Q

What are some side effects of NSAIDS?

A

1) Can cause peptic ulceration
2) Diclofenac increases the risk of cardiovascular events and CVD

38
Q

How might a high protein diet affect medication?

A

-May reduce the effects of theophylline due to increased renal clearance
- May reduce the effects of L-dopa due to decreased intestinal absorption and interferes with transport from the bloodstream to the brain

39
Q

How might salt restriction affect medications?

A

May increase serum lithium to toxic levels as sodium is involved in the active transport of lithium and low levels can cause lithium to accumulate in cells

40
Q

How can high fibre diets affect some medications?

A

High fibre diets may reduce serum levels of tricyclic antidepressants eg amitriptyline as they can decrease intestinal absorption

41
Q

What are some side effects and complications of statin use?

A

GIT disturbance
Headaches
Fatigue
Insomnia
Myositis
Statin induced myopathy
- Statin use can lead to rhabdomyolysis - the breakdown of muscle cells. Can result in kidney disease and even failure. care should be taken with foods or supplements that may interfere with metabolism.

42
Q

Name one natural alternative to statins and describe the mechanism

A

Red yeast rice is a combination of mevinic acids and derivatives (identical to the active in lovastatin) which exhibit cholesterol lowering activity

43
Q

Which nutrients may get depleted by PPIs and why?

A
  • Calcium: reduced gastric absorption can lead to decreased bone mineral density, inhibition of osteoclast activity and an increased fracture risk
  • B12: Gastric acid is needed for the release of B12 from proteins to help with intestinal absorption
  • Magnesium: due to decreased intestinal absorption
    -Iron: reduced absorption potentially leading to iron deficiency anaemia

Also beta carotene, chromium, folate, C and zinc due to reduced gastric acid levels

44
Q

What are PPIs prescribed for and what is the mode of action?

A

GORD, prevention of NSAID associated ulcers, triple therapy with antibiotics for gastric/duodenal ulceration
- Blocks the gastric cells proton (hydrogen pump)

45
Q

Describe a 5R approach for the withdrawal of PPIs to avoid rebound reflux

A

1) Remove
Trigger foods - acidic, alcohol, caffeine, spicy, fatty, dairy, chocolates. Identify intolerances, stop smoking. Avoid overeating and fluid with meals. Elevate head of bed- prone position, last meal 4 hours before bed

2) Replace (introduce)
-Nutrient dense meals to replace deficiencies and supplements eg magnesium and B12. general multivitamin and mineral
-Digestive enzymes/ bitters/ betaine HCI

3) Repopulate
- introduce prebiotics- some clients may suffer from SIBO after long term acid suppression

4) Repair:
- To protect and repair the gut lining- use slippery elm, marshmallow, chamomile, glutamine

5) Rebalance:
- Reduce and manage stress- acupuncture, aerobic exercise. Stress is a key trigger

46
Q

Which nutrient interactions are associated with warfarin?

A
  • Major changes in diet (salads/ green vegetables) - indoles and vitamin K can reduce the anticoagulant effect of warfarin and alcohol can affect anti- coagulant control
  • Pomegranate juice increases the INR by inhibiting the CYP450 enzyme that metabolises warfarin
  • High doses of vitamin E inhibit platelet aggregation and should be avoided with warfarin .
47
Q

What are ACE inhibitors/ angiotensin antagonists and what are some side effects?

A

Prescribed for heart failure and hypertension

  • Hyperkalaemia, postural hypotension, constipation, diarrhoea, nausea and vomiting
  • ACE inhibitors cause a persistent dry cough (due to a rise in bradykinin) and angioedema
48
Q

What nutrient deficiencies may happen with diuretics and why?

A
  • Calcium, magnesium, potassium, folate, vitamins B1, B6 and C due to increased urinary loss
49
Q

What is the mode of action of a diuretic and what are some side effects?

A

Diuretics are prescribed for oedema due to heart failure and hypertension.
They inhibit reabsorption of filtrate from various sections of the nephron (ie increased urine output), decreasing blood volume and pressure
- hypokalaemia, hypotension, GI disturbance, impotence. Milk alkali syndrome may occur when thiazides are combined with large quantities of calcium carbonate

50
Q

What is the mode of action of digoxin and what nutrient reactions are there?

A

Prescribed for atrial fibrillation and heart failure. Increases force of myocardial contraction and reduces conductivity within the atrial- ventricular node
Hawthorn can increase myocardial contraction and concomitant use may require dose to be reduced

51
Q

What are some natural alternatives to antacids?

A
  • Diet and lifestyle changes- chew food well, fluids away from meals
  • Demulcent/ anti-inflammatory herbs- aloe vera juice, slippery elm, liquorice, marshmallow root
  • Avoid caffeine,
  • lose weight
  • manage stress, breathing exercises to support shift into parasympathetic state
52
Q

What are some nutrient interactions with warfarin?

A
  • Warfarin antagonises effects of vitamin K- a cofactor for the four clotting factors
  • High doses of vitamin E can inhibit platelet aggregation , and may cause an additive effect alongside warfarin- hemorrhage risk
  • Pomegranate juice can inhibit the CYP450 enzyme that metabolises warfarin, increasing the INR- measure of how long it takes blood to clot
53
Q

What interactions may occur with levothyroxine?

A

1) calcium and Cow’s dairy reduces the absorption of levothyroxine and doses should be separated by four hours
2) Iron supplements reduce absorption- 4 hours apart
3) Caffeine can reduce absorption- should be taken an hour apart
4) Soy decreases absorption- seperate by at least 4 hours

54
Q

What is serotonin syndrome? What are the side effects?

A

Serotonin syndrome is rare but can be fatal
-Associated with an excess of serotonin due to therapeutic drug use, an overdose or interactions between drugs. It can happen when coming off one serotegenic drug and starting another eg SSRI- MAOI (mono-amine oxidase inhibitor)
- Caution with st johns wort and 5HTTP due to additive effect

Side effects include: Confusion, disorientation, exaggerated reflexes, hypo/ hyper tension, fever, sweating, abnormal movements

55
Q

Describe the mode of action and the associated side effects of NSAIDS

A

NSAIDS inhibit the activity of cyclooxygenases (COX-1 and COX-2) , thereby inhibiting prostaglandin synthesis.
- These prostaglandins play a vital role in gastric mucosal defence, and so NSAIDS can increase the risk of gastric bleeding and ulceration
- Some NSAIDS selectively inhibit COX-2 and allow COX-1 to synthesis the prostaglandins that have gastro protective effects. However these are associated with increased risk of cardio- vascular events in those with heart disease.
- NSAIDS can also block renal prostaglandins that normally dilate blood vessels in the kidneys- leading to reduced blood flow and oxygen supply= acute kidney damage.

56
Q

What contraindications and interactions are there with NSAIDS?

A

-shouldn’t be used with peptic ulceration, history of gastrointestinal bleeding , hypersensitivity to aspirin and IBD
- concomitant use with warfarin increases bleeding risk
- Concomitant use of NSAIDS with high doses of nutrients and herbs with antiplatelet activity may increase risk of bleeding (garlic, turmeric and vitamin E)

57
Q

Name 5 alternatives to NSAIDS

A

1) Willow bark reduces inflammation and fever and has analgesic properties. Can safely be used alongside NSAIDS as no antiplatelet effects
2) Turmeric (curcumin), ginger and boswelia are COX inhibitors
3) Quercetin inhibits LOX and COX pathways and downregulates NF-kB. Onions, asparagus, apples, berries
4) Anti inflammatory / alkalising diet with lots of fruit and veg- rich in flavonoids and chlorophyll

58
Q

What are corticosteroids prescribed for and what is their mode of action?

A
  • Prescribed for asthma, eczema, IBD, hypersensitivity reactions and autoimmune conditions
  • Corticosteroids bind to DNA to modulate protein synthesis, stimulates the production of a glycoprotein called lipocortin, which inhibits the activity of phospholipase A2 and hence inflammatory mediators.
59
Q

What are some natural alternatives to corticosteroids?

A
  • Anti inflammatory diet
  • nutrients and herbs that inhibit inflammatory mediators eg EFAs, quercetin, turmeric and ginger
  • liquorice root has be shown to modify or increase the bodies levels of cortisol
60
Q

What interactions are possible with corticosteroids?

A
  • If large levels of liquorice are given with corticosteroids, may cause hypokalemia
    -possible interactions with liquorice and fludrocortisone due to mineral corticoid effects

Nutrition two (10 decks)

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