Nutritional Pharmacology Flashcards
What do nutritional therapists need to know about drugs?
- Side effects
- Food and supplements may interact
- Drugs can cause nutrient depletions
What is a medicine according to the MHRA?
A substance or combination of substances that have properties for treating or preventing disease in human beings.
Drugs - modify physiological functions by exerting a pharmacological, immunological or metabolic action.
What are the four supply routes for drugs?
- Prescription only (POM)
- Controlled - e.g. codeine / morphine
- Phamacy only (PO)
- General sales list (GSL)
What are the two types of OTC drugs?
2 Reasons why clients self medicate?
PO - pharmacy only
GSL - general sales list
- treat a minor ailment
- support a chronic illness not fully controlled
6 common types of OTC drugs and an example of each \
AP CLAD
Analgesics - codeine, paracetomol, asprin
PPI’s - omeprozole
Cough mixtures - diphenhydramine
Laxatives - senna, bisacodyl
Anti-histamines - chlorphenamine, cetrizine
Decongestants - pseudoephedrine
2 key elements of a drug and examples
- Active ingredient - deliver mode of action and often linked to side effects - ibuprofen
- inactive - alter physical properties - fillers, colouring, preservatives, lactose, gluten
- can trigger allergic reactions and food intolerances
2 terms used for naming a drug and example
Generic name of the active ingrdeint e.g. paracetomol
Brand name - e.g. panadol
Nutritional therapistcs should use the generic name.
What do these terms mean:
Drug class
Indication
Contraindication
Drug class - penicillian is an antibiotic
Indication - what the drug is intended for
Contraidication - when the drug must not be used
What is the difference between a drug and a nutrient?
Example
Drugs supress and manage symptoms
Nutrients encourage the body to resotre homeostasis and heal.
Willow bark / salix alba / salicin - gastric irritant in paracetomol
Willow bark doesn’t convert until it reaches the bloodstream and body tissues.
What does pharmacokinetics and pharmacodynamics mean?
Pharmacokinetics - movement of drugs within the body - 4 processes (ADME) - absorption, distribution, metabolism and elimination.
Pharmacodynamics - how drugs interact with the body and exert their side effects.
Describe what is meant by ADME
Abosrbed - entering the body and absorption into the blood steam
Distuibution - in the bloodstream the drug is distributed to its target site.
Metabolised - Once the drug and receptor have interacted the drug returns to the blood stream to be taken the liver to be metabolised.
Excretion - once metabolised excretion is by urine or bile.
What is first pass hepatic metabolism?
Drugs are obsorbed in the GIT and taken by the portal vein to the liver to be metabolised.
This means that drugs may be less concentrated by the time they reasch systemic circulation.
This type of medicine should be administered by a different route e.g. nitro glycerine spray for angina.
What 2 main factors determine if a drug reaches its target site of action in the body?
- Bioavailability - proportion of the drug that reaches the blood stream for distribution.
- Route of administration - e.g. oral, sublingual, suppository, injections, creams, patches.
4 main routes of drug administration and examples
Oral - tablets, capsules, liquids - absorption via small intensine.
Sublingual / buccal - glyceryl trinitrate spray - bypasses liver
Topical - local effect - creams, patches, ear and eye drops
Systemic - inhalation
Parenteral - injections - intravenous, sub-cutaneous, intro-muscular
4 factors that impact drug absoprition
GIT motility - diarroea reduces absorption
Malabsorption - e.g. coeliac disease
Other substances - iron reduced with milk
Lipid soluble and small molicule easier to absorb
Acidic drugs absorb quicker in an acidic environment.
4 factors that impact a drug’s distribution
- binding to plasma proteins with effects concentration
- binding to other tissues - tetracycline binds to calcium in bones and teeth
- Accumulation in lipids - e.g. anaesthetics
- Natural barriers e.g. BBB, placental barrier.
How are drugs changes from a lipid soluable to water-soluable for excretion?
Phase I - chemically altered using cytochrome P450 enzyme family
Phase II - Conjugated to a more water-soluable product.
What are the major and minor excretion routes for drugs and what can impact them?
Major - urine, faeces
Minor - exhaled air, sweat, saliva, tears
Renal - small water-soluble molecules - renal dysfunction can impact
Some lpid soluable drugs may be re-absorbed - entero-hepatic circulation.
What factors influence the pharmacodynamics of a drug?
Advancing age
Malnutrition
Medical conditions
Dosage
Side effects and drug interactions
Administration route
What are common side-effects and how are drug side effects classified
Nausea and vomiting
Dizziness
Constipation
Diarrhoea
Indigestion
Skin rashes
Dry mouth
Very common, common, uncommon or rare
Examples of long-term drug side effects?
Nutrient deficiencies - metformin and B12
Metabolic - omeprozole and low magensium
Dependence - diazepam, opiate analgesics
Osteoporosis - corticosteroids
Gout - thiazide diuretics
Cardovascular disease - diclofenac (NSAID)
Peptic ulceration - NSAID
5 side effects of PPIs
A BBB DM
Acid rebound
B12 deficiency
Bacterial infections
Bone fractures
Dementia
Magnesium deficiency
Diclofenac story
Increases the risk of cardiovascular events but was commonly prescribed
Guidance changed in 2013 but OTC sales via pharmacies still permitted.
3 steps if you think a client is experiencing side effects?
Check - againsts drugs resource
Advice - client to consult GP or specalist
Ensure - your recommendations do not interact
5 substances that can interact with drugs
Other drugs
Herbal medicine
Food and drink
Nutritional supplements
Chemicals in the environment
What type of drugs shoudl nutritional therapists exercise caution for?
Narrow Therapeutic Index drugs
- drugs that can become dangerously toxic or ineffective with small changes in blood concentration
e.g. digoxin, warferin, lithium
Garlic interactions
Cholesterol and blood pressure drugs e.g. atorvastatin
Anticoagulant and antiplatelet drugs - 4g/day little effect
Garlic throughout the day but high dietary intake and supplements could cause interactions.
Ginkgo interactions
Anticoagulant and antiplatelet medication - stop 1 week before surgery
CYP induction drugs monitor - e.g. anti-epileptic, diabetic, HIV drugs, omeprazole.
Grapefruit / Pomegranate interactions
Inhibits CYP3A4 in intestinal wall for up to 24 hours but NOT liver
Caution drugs metabolised by this pathway (50% all drugs) including digoxin and statins
Green vegetables interactions
Reduce effect of anticoagulants - warfarin
Contain Indoles increase warfarin metabolism and vitamin K reduces effect
Vitamin K is a coagulant
Soy interactions
Levothyroxine - decreases absorption
May interfere with oestrogen-blocking drugs e.g. Tamoxifen due it its isoflavone content.
Warfarin - may reduce effectiveness.
Dairy / Calcium interactions?
Antibiotics (quinolones & tetracycline) & bisphophonates - may bind to and reduce absorption.
Levothyroxine - reduces absorption. Take 4 hours apart.
bisphophonates - slow down / help prevent bone loss.
4 nutrients PPI’s deplete and what is the mechanism?
Reducing gastric acid levels impacts absorption
Magnesium
Folate
B12
Zinc
Beta-carotine
Calcium
Chromium
Iron
Vit C
4 nutrients steroids (prednisolone) depletes and the mechanism?
Increases urinary excretion / losses from bones
Calcium
Vit D
Magnesium
Zinc
Folate
Chromium
Potassium
1 nutrient statins deplete and the mechanism?
Block mevalonic acid synthesis - precursor to cholesterol and CoQ10
CoQ10
4 nutrients antibiotics deplete and the mechanism
Destruction of microflora may reduce absorption of B vitamins and vitamin K
B1
B2
B5
B6
B12
Vitamin K
2 nutrients metformin depletes and the mechanism
Malabsorption
Folate
B12
4 Nutrients diuretics depletes and the mechanism
- think water-soluable vitamins
Increased urinary loss
B1
B6
Folate
C
Magnesium
Calcium
Potassium
2 nutrients antacids deplete and the mechanism
Increased gastric pH may reduce solubility and absorption
Aluminium can bind to calcium preventing absorption
Calcium
Iron
Cromium
Folate
1 nutrient thyroxine can deplete and the mechanism
Calcium
Increased bone turn over may lead to increased urinary calcium loss.
4 nutrients the OCP can deplete and the mechanism
Reduced absorption, increased excretion.
Vitamin A - reduced liver storage
Zinc -
B12 - reduced protein binding, increased requirement
Folate
Magnesium
B6
B2
B1
C
What is the impact of alcohol on drug metabolism
3 key points
Alcohol may complete for the same metabolising enzymes
- Long-term can activate drug-metabolising enzymes - decreasing drug availability
- May transform drugs into toxic chemicals that can damage the liver
- May magnify the inhibitory effects of sedative and narcotic drugs
2 types of drugs where alcohol has a specific negative impact
Cimetidine (for gastric ulcers) reduces stomach acid which inhibits alcohol dehydrogenase.
Slow-release depot injections - can be forced out of storage in muscle resulting in overdose. E.g. antipsychotic drugs.
Why should grapefruit (/pomegranate) juice be avoided with statins?
Inhibits the CYP3A4 enzyme in intestinal wall for 24 hours needed for absorption of the drug.
Key cautions with warfarin
Garlic and green leafy veg can have an additive effect due to the vitamin K which supports blood clotting
How can metformin contribute to feeling fatigued
Contributes to malabsorption of folate and B12.
What are ACE inhibitors / Angiotensin II antagonists?
Examples, contraindications and side effects.
For heart failure, hypotension
ACE inhibitors - ramipril
Angiotensin II antagonists - losartan
Contra - pregnancy / breastfeeding
Side effects
dizziness
constipation / diarrhoea
nausea / vomiting
ACE inhibitors - persistent dry cough (rise in bradykinin)
Avoid potassium-rich diets
What are statins used for?
Examples, contraindications and side effects.
Hypercholesterolaemia
Hypertriglyceridemia
Prevention of cardiac events in those with atherosclerotic disease or diabetes
Atorvastatin
Simvastatin
Inhibit HMG CoA reductase - to reduce cholesterol (+CoQ10) synthesis
Contra - pregnancy / breast feeding / liver diease
GIT disturbance
Headache
Fatigue
Insomnia
Stain-induced myopathy
Inflammation of muscles - can lead to a breakdown of muscle cells (rhabdomyolysis)
Caution: grapefruit / pomegranate juice
What is rhabdomyolysis and what drug is it linked to?
breakdown of muscle cells
Statins
What naturopathic supplement has an additive effect with statins?
Red rice yeast
May increase side effects if taken with statins
What are diuretics used for?
Examples, contraindications and side effects.
Oedema due to heart failure
Hypertension
Furosemide (loop diuretic)
Bendroflumethiazide (thiazide diuretic)
Spironolactone (potassium-sparing diuretic)
Inhibit reabsorption of filtrate from nephron - increasing urine output.
