Nutritional Pharmacology Flashcards
What is a Medicine?
“Any substance or combination of substances
presented as having properties for treating
or preventing disease in human beings.”
Examples of analgesics
codeine, paracetamol, aspirin, ibuprofen
Examples of laxatives
senna, bisacodyl
Example of proton pump inhibitor
Omeprazole
Example of anti-histamines
chlorphenamine, cetirizine
Example of decongestants
pseudoephedrine
What is a drug’s active ingredient?
Part of the drug that is intended to deliver its mode of action and is responsible for side effects
Drug Terminology
Drug Class
Indication - what is it intended for
Contraindication - When the drug must
not be used
Side effects
Interactions - A drug’s activity is affected by another
substance causing an increase, decrease or a new effect.
What is pharmacokinetics?
Movement of drugs within the body
What is pharmacodynamics?
How drugs interact with the body to
exert their effect
What are the 4 key processes in pharmacokinetics?
Absorption
Distribution
Metabolism
Elimination
(ADME).
What is First Pass Hepatic Metabolism?
Drugs that are taken orally are absorbed from the GIT and taken via the portal vein into the liver to be metabolized. This means the drug concentrations can be reduced by the time they enter the systemic circulation
What are the two main factors that determine whether a drug reaches its target site of action in the body?
Bioavailability
Route of administration — how a drug
is administered e.g., oral tablets, sublingual
Examples of drug administration?
Oral
Sublingual/Buccal - bypasses liver metabolism
Topical
Parenteral - injections
What factors affect drug metabolism related to the body?
Gastro-intestinal motility: Diarrhoea increases motility and reduces absorption.
Malabsorption states reduce absorption e.g., Coeliac disease.
Presence of other substances: E.g., absorption of iron is reduced when given with milk
What factors affect drug metabolism related to the medicine?
Absorption is greatest for lipid soluble and small molecule drugs.
Acidic drugs absorb quicker in
an acidic environment e.g., stomach.
A liquid medicine will absorb quicker than a solid tablet
How can drug distribution be affected in the body?
Binding to plasma proteins
Binding to other tissues
Accumulation in lipids e
Natural barriers to distribution
What is Phase I in drug metabolism?
Drug / toxin is altered chemically to make
it suitable for Phase II reactions or for excretion.
Involves the cytochrome P450 enzyme family.
What is Phase II in drug metabolism?
Molecules from Phase I (or in some
cases unchanged drugs) are conjugated to a more water-soluble product and aid excretion
What are the main routes of drug excretion?
Urine
Faeces
What are the minor routes of drug excretion?
Exhaled air
Sweat
Saliva
Tears
What Affects Pharmacodynamics? (how drugs interact in the body to exert their effects)
Advancing age
Genetic mutations
Malnutrition
Medical conditions e.g., Parkinson’s disease, Alzheimer’s disease.
What are the side of effects of PPI usage?
Bone fractures.
Hypomagnesaemia (low blood magnesium).
Vitamin B12 deficiency.
Bacterial enteric infections
Rebound acid hypersecretion (when PPI is stopped).
Kidney disease.
Dementia.
Which other substances can interact with drugs?
Drugs.
Herbal medicines.
Food and drinks.
Nutritional supplements.
Environmental chemical agents
What are Narrow Therapeutic Index (NTI) drugs?
Drugs that may become dangerously toxic
or ineffective with only relatively small
changes in their blood concentrations.
Examples of Narrow Therapeutic Index (NTI) drugs
Digoxin
Phenytoin,
Theophylline
Warfarin
Lithium
What drugs can Garlic interact with?
Cholesterol and blood pressure drugs
What drugs can Gingko interact with?
Should be avoided with any antiplatelet and anti-coagulant medication.
What drugs can Grapefruit & Pomegranate interact with?
Selectively inhibits CYP3A4 in the
intestinal wall for up to 24 hours, but
NOT in the liver.
Caution is advised drugs that are metabolised via this pathway -
CYP 3A4 is involved in the
metabolism of over 50% of all drugs.
What drugs do green vegetables interact with?
Anticoagulants such as warfarin.
What compounds in green vegetables increase the metabolism of warfarin?
They contain indoles which increase
the metabolism of warfarin, and also
contain vitamin K, which reduces the
anti-clotting effects of warfarin
What drugs do Soy interact with?
Decreases absorption of levothyroxine:
May also interfere with oestrogen-blocking drugs
May reduce the effectiveness of warfarin
What drugs do dairy / calcium interact with?
Calcium can bind to antibiotics like the quinolones and tetracycline
Reduces levothyroxine absorption
What nutrients are depleted by PPI’s?
Beta-carotene, calcium
chromium, iron, magnesium,
folate, vit. B12, vit. C, zinc.
How are nutrients depleted with PPI’s?
Reduced gastric acid levels inhibit
absorption.
What nutrients are depleted by Steroids
(Prednisolone)?
Calcium, vit. D, chromium, folic acid, magnesium, potassium, strontium, zinc.
What nutrient is depleted by Statins?
CoQ10
How is CoQ10 depleted by statins?
Block synthesis of mevalonic acid, which is a precursor of cholesterol and coenzyme
Q10.
What nutrients are depleted by antibiotics?
Biotin, pantothenic acid (B5), pyridoxine (B6) riboflavin (B2), thiamine (B1), vit. B12,
vit. K.
What nutrients are depleted by Metformin?
Vitamin B12, folate.
How are nutrients depleted by Metformin?
Malabsorption of B12 and B9.
How are nutrients depleted by antibiotics?
Destruction of normal intestinal microflora may lead to decreased production of
various B vitamins and vitamin K
What nutrients are depleted by Diuretics?
Calcium
Magnesium
Potassium
Folate,
vits. B1, B6, C
How are nutrients depleted by Diuretics?
Increased urinary loss.
What nutrients are depleted by Antacids?
Calcium
Iron
Chromium,
Folate.
How are nutrients depleted by Antacids?
Increased gastric pH may reduce
solubility and absorption.
Aluminium containing antacids can bind to
calcium preventing absorption.