Actions and Uses of Medicines (305) Flashcards
What is the use of the BNF?
The BNF is the dispensing guide.
Who produces the BNF?
The BNF is jointly produced by the British Medical Association and the Royal Pharmaceutical Society of Great Britain.
How often is the BNF published?
The BNF is published twice yearly.
What is the British Pharmaceutical Codex used for?
Contains the master formula of BPC products including their ingredients, actions, users and storage requirements.
What does the British Pharmacopoeia contain?
Details standards of purity and strength for medical substances, products and dressings as well as products that are suitable for extemporaneous dispensing.
What is the use of the European Pharmacopoeia?
The European Pharmacopoeia was created to permit the free circulation of drugs within the European community.
What is the use of Martindale: the extra Pharmacopoeia?
Provides information on nomenclature, physical and pharmaceutical properties, adverse effects, actions and uses of drugs.
How often is Martindale published?
Martindale is published every 3 years.
What information is included in the Association of British Pharmaceutical Industry (APBI) Data Sheet Compendium?
Contains copies of the data sheets of all participating companies. Information is given on drug presentations, uses dosage, administration, contraindications, warnings and pharmaceutical precautions.
How often is the Association of British Pharmaceutical Industry (ABPI) Data Sheet Compendium published?
The Association of British Pharmaceutical Industry (ABPI) Data Sheet Compendium is published annually.
What is the use of the Monthly Index of Medical Specialties (MIMS)?
Can be used as a reference and a prescribing guide. It lists proprietary preparations that can be prescribed or recommended.
How often is the Monthly Index of Medical Specialties (MIMS) published?
The Monthly Index of Medical Specialties (MIMS) is published monthly.
What is the Patient Information Leaflet Compendium used for?
It includes copies of patient information leaflets found in proprietary medicine packs.
How often is the Patient Information Leaflet Compendium produced?
The Patient Information Leaflet Compendium is produced annually.
What is the use of the use of the Chemist and Druggists Guide to OTC Medicines?
Includes general advice in specific categories, including monographs detailing directions for use, cautions and costs as well as herbal and homeopathic products.
What is another publication with similar information to the Chemist and Druggist Guide to OTC Medicines?
The OTC Directory contains similar information to the Chemist and Druggist Guide to OTC Medicines
What is the use of Medicines, Ethics and Practice - a Guide for Pharmacists?
The Medicines, Ethics and Practice - a Guide for Pharmacists is a practical guide to the legal classification of medicinal products incorporating the ‘code of ethics’ and the ‘guide to good dispensing practice’
How often is the Medicines, Ethics and Practice - a Guide for Pharmacists updated?
The Medicines, Ethics and Practice - a Guide for Pharmacists is updated twice yearly.
How else can the BNF be accessed other than its book format?
Online or on the app.
What is pharmacology?
Pharmacology is the study of actions and uses of medication, mechanisms and adverse effects.
What is pharmacokinetics?
Pharmacokinetics is the branch of pharmacology concerned with the movement of drugs within the body and the way in which the body affects drugs with time. (absorption, distribution, metabolism, excretion)
What is pharmacodynamics?
Pharmacodynamics is the branch of pharmacology concerned with the effect of drugs and the mechanism of their action.
ie how the drug affects the body.
What is a receptor?
A receptor is a protein molecule with a tertiary structure with a complementary binding site to that of the molecules to which it binds. Once the receptor is attached, it activates it to have an affect on the cell.
What is a agonist?
An agonist is a substance which initiates a physiological response when combined with a receptor.
What is an antagonist?
An antagonist is a substance that binds to a receptor and blocks it so the agonist cannot bind, blocking or dampening the biological response.
What is a partial agonist?
In pharmacology, partial agonists are drugs that bind to and activate a given receptor but have only partial efficacy at the receptor relative to the full agonist.
What is competition?
Drugs or other molecules that compete for the same receptor.
What is the result of a non-competitive inhibiter binding?
No pharmacological effect.
What will happen if a competitive inhibiter binds?
Capable of reversing or altering an effect already achieved.
What is an enzyme?
An enzyme is a biological catalyst that speeds up the rate of reaction.
What are ion channels?
Ion channels are the ubiquitous transmembrane proteins that allow the selective transport of ions and solutes across the plasma membrane.
What are the four basic processes involved in pharmokinetics?
- absorption
- distribution
- metabolism
- excretion
What affects the pharmokinetics of a drug?
The make up of a drug affects where the drug is absorbed, where it is distributed to, where and how effectively it is metabolised and how rapidly it is excreted.
What drugs are not absorbed by the body?
Almost all drugs apart from those that are administered intravenously must be absorbed before they can have effect on the body.
What is bioavailability?
Bioavailability is the term used to refer to the proportion of an administered drug that has reached the circulation and is able to have effect on the body.
What drugs are said to have 100% bioavailability?
Drugs that are administered intravenously are said to have 100% bioavailability.
Where are drugs that are administered orally absorbed?
Drugs administered orally are absorbed from the gastro-intestinal tract.
Where are drugs metabolised?
Once absorbed in the gastro-intestinal tract, the drug is carried via the hepatic portal vein to the liver to be metabolised.
What is the first-pass effect?
The removal of the drug by the liver before the drug has become available for use is termed the ‘first-pass effect’.
Give an example of a drug that may be totally inactivated by the first-pass effect.
Glyceryl trinitrate is completely inactivated by the first-pass effect.
What transport mechanisms exist to aid the transport across lipid membranes?
- passive diffusion
- facilitated diffusion
- active transport
- pinocytosis
What is pinocytosis?
The ingestion of liquid into a cell by the budding of small vesicles from the cell membrane.
What is passive diffusion?
Passive diffusion is the movement of molecules down a concentration gradient from an area of high concentration to an area of low concentration.
Is energy required for diffusion?
No energy is required for diffusion.
What is facilitated diffusion?
Facilitated diffusion is the movement of lipid insoluble molecules across the phospholipid bilayer by combining with a carrier protein.
Does facilitated diffusion require energy?
Facilitated diffusion does not require energy. It is a passive process. The molecules are just too large/insoluble to move across the membrane, they are still moving down a concentration gradient however.
What is active transport?
Active transport is the movement of molecules against their concentration gradient using ATP as a source of energy. The molecules move through transmembrane proteins which act as pumps.
What are some factors that will affect the absorption of the drug from the GI tract?
- gut motility
- gastric emptying
- surface area
- gut pH
- blood flow
- presence of food and fluid in the GI tract
- antacids
- drug competition
How does the presence of food in the gut affect the rate of drug absorption?
The presence of food can both increase and decrease the rate of absorption of a drug depending on both the drug and the meal consumed. Fats slow the rate of gastric emptying.
Which form of drug is absorbed quicker, liquid or solid?
Liquid drugs are absorbed quicker than solid drugs.
How does parenteral administration affect the rate of absorption of a drug?
- intravenously → straight into blood supply
- intradermal → diffuses slowly into local capillaries
- subcutaneous → a little faster than intradermal
- intramuscular → absorbed quickly due to rich blood supply
TRUE or FALSE
Drugs that are applied topically are absorbed less than those administered by either the oral or parenteral routes?
TRUE!
What is the rate of absorption for drugs administered rectally?
Rapid, due to the vascularity of the mucosa.
What is the rate of absorption for drugs administered sublingually?
Rapid, due to the vascularity of the mucosa.
What is polypharmacy?
Polypharmacy is the concurrent use of multiple medications by a patient. Polypharmacy is most common in the elderly.
What is the plasma protein that some drugs bind to?
Albumin is the plasma protein that some drugs bind to.
If a drug is bound to albumin is it active or inactive?
If a drug is bound to albumin it is said to be inactive and cannot have pharmacological action.
Which drugs can fairly readily cross the blood-brain barrier into the CNS?
Lipid soluble drugs can cross the blood-brain barrier and enter the CNS.
Where are lipid soluble drugs stored?
Lipid soluble drugs are stored in fat tissues.
What does drug metabolism involve?
Drug metabolism involves breaking a drug down or adding a chemical that makes it easier to pass it into the urine or stool.
Where does drug metabolism take place?
Most drug metabolism occurs in the liver; but drug metabolism also occurs in the kidneys, intestinal mucosa, lungs, plasma and placenta.
What is drug tolerance?
Drug tolerance is when a drug is repeatedly given and metabolism becomes more effective and therefore a larger dose of the drug may be required in order to produce the same effect.
What are factors that affect a person’s ability to metabolise drugs?
- genetic difference
- age
- disease processes
How does age affect a person’s ability to metabolise drugs?
First-pass metabolism may be reduced, resulting in increased bioavailability. Delayed production and elimination of metabolites may prolong drug action so may need reduced dose.
What disease might affect drug metabolism?
Liver disease will affect drug metabolism.
Which organ excretes most drugs and metabolites?
The kidneys excrete most drugs and metabolites.
What factors affect the rate at which a drug is excreted by the kidneys?
- presence of kidney disease
- altered renal blood flow
- pH of urine
- concentration of the drug in plasma
- molecular weight of the drug
Drugs that are secreted into bile are excreted how?
Drugs that are secreted into bile will pass through the large intestine and be excreted in the faeces.
What is the half life of a drug?
The half life of a drug is the time it takes for the concentration of the drug in the blood to fall to 50% of its original value.
Why is knowing the half life of a drug important?
Knowing the half life of a drug means standard dose intervals can be set up to maintain stable plasma concentration of a drug.
Why do the young have problems related to their ability to metabolise and excrete drugs?
The very young have problems related to their ability to metabolise and exrete drugs because their hepatic enzyme systems are not fully effective.
Why do the elderly have problems related to their ability to metabolise and excrete drugs?
In the elderly metabolism is delayed in the liver and their is a decline in renal function resulting in delayed excretion of the drug by the kidney, prolonging the drug action.
What factors might affect a persons response to a drug?
- age
- body weight
- pregnancy and lactation
- nurtitional status
- food-drug interactions
- disease processes
Why might someone’s body weight affect their response to a drug?
The size of an individual will affect the amount of drug that is distributed and available to act.
How might a drug affect a developing foetus?
Some drugs can cross the placenta and affect the foetus. If the drug is teratogenic this may result in a foetal malformation.
TRUE or FALSE
Drugs can be transferred to an infant via the breast milk.
TRUE!
Drugs can be transferred to the suckling via the breast milk and have adverse reactions on the child.
How might inadequate dietary protein affect a patient’s response to a drug?
Inadequate dietary protein may effect enzyme activity and slow the metabolism of drugs.
How might a reduction in plasma protein affect a patient’s response to a drug?
A reduction in plasma protein may mean that there is an excess of drug available for activity.
What will enhance the absorption of iron sulphate?
Vitamin C enhances the absorption of iron sulphate.
What reduces the absorption of tetracycline?
Dairy produce will reduce the absorption of tetracycline.
How do hepatic diseases (hepatitis, cirrhosis, liver failure) affect a patient’s response to a drug?
Hepatic diseases will reduce metabolism of drugs and lead to a gradual accumulation of drugs and may lead to toxicity.
How do circulatory diseases affect a patient’s response to a drug?
Circulatory diseases, i.e heart failure, will reduce distribution and transport of drugs.
How do mental and emotional factors affect a patient’s response to a drug?
Mental and emotional factors may affect a patient’s ability to comply with a drug regime.
What factors may affect the absorption of a drug?
- mobility
- gastric emptying
- blood supply
- drug form
- pH
- presence of food/drink
What factors may affect the distribution of a drug within the body?
- blood flow
- concentration gradient
- blood-brain barrier
- drug form
- body weight
What factors affect drug metabolism within the body?
- age
- liver function
- diet
- genetics
What factors affect excretion of a drug?
- kidney function
- blood flow (through the kidneys)
- pH of urine
- age
What is pharmacodynamics?
Pharmacodynamics is the way that a drug affects the body