1. Introductory pharmacology Flashcards
What is a drug?
A drug is “any chemical which affects physiological function in a specific way”
What is pharmacology?
How the function of living things is altered by chemical agents
What is the ending ‘PRIL’ representative of?
Angiotensin converting enzyme inhibitors - they block the synthesis of vasoconstrictor peptide angiotensin 2. Prevents the constriction of blood vessels.
What is the first source of drugs?
Individual chemicals purified from cells and tissues. e.g. plants
Where does atropine come from?
Atropa belladona
Where does morphine come from?
Papaver somniferum
What is another source of drugs?
Individual chemicals purified from cells and tissues e.g amphibians, reptiles etc
What can be derived from pigs?
Porcine insulin
Where does streptokinase come from?
Haemolytic bacteria
What is another source of drugs? and give examples
Chemical synthesis by pharmaceutical industry e.g. ephedrine paved the way for salbutamol.
What is another source of drugs? and give examples
Chemical synthesis by the pharmaceutical industry e.g. drug discoveries
What is the fifth source of drugs and give examples
Large scale production of recombinant human proteins, e.g. , human insulin. And antibodies to human proteins e.g. cytokine mediators for treating inflammatory disease.
What ways do most drugs bind?
Reversibly via ionic bonds. Van Der Waals are also a factor.
What can happen when you take drugs.
They cause a desired effect in one target but can cause an adverse effect in the same target but in a different area.
In practice what are drugs?
Selective rather than specific - which means unwanted effects are common.
How should you think of drugs?
They’re like the ball you push shapes into, some shapes can fit in the other holes although they will not be as good a fit they will still fit. Thats how adverse affects come about.
What are the molecular targets for drug action?
Proteins - ion channels - membrane transporters - enzymes - non-cellular proteins - receptors Nucleic acids Miscellaneous targets
What are the different types of ion channels are drug targets?
Blockers
Allosteric modulators
- Inhibitor
- Facilitor
What do blockers do and whats some examples?
They physically block the open ion channels. E.g. lidocaine - local anaesthetic. Blocks the Na+ ion channel therefore no action potentials can be produced.
What do allosteric modulators do?
They chase a shape change in channel proteins on binding elsewhere on the protein.
What is the difference between an allosteric inhibitor and facilitator?
Inhibitors cause less ions to enter - less response and facilitator cause more ions to enter - greater response
What is an inhibitor modulator - Amlodopine
Treats hypertensions, angina pectoris. Blocks electrically gated Ca2+ ion channels. It dilates blood vessels causing blood pressure to reduce and coronary muscle relaxation. This means coronary blood flow is increased and more oxygen gets to the heart.
What is a facilitator modulator - Benzodiazepine
Binds to GABA(a) to enhance channel opening by GABA. The increased Cl- conductance reduces neuronal excitability.
What is GABA?
An inhibitory neurotransmitter, therefore is you increase the incidence of GABA it becomes less inhibitory.
What are two examples of membrane transporters as drug targets?
Inhibitors and false substrates
What do inhibitors do? e.g.
They block the transport mechanism. E.g. furosemide. It is a loop diuretic which prevents NaCl reabsorption in the thick ascending loop of henle. Therefore more urine is produced. It does this by inhibiting the Na+/K+/2Cl- co transporters in the luminal membrane combining with the chloride binding site.
How do false substrates work? e.g. Amphetamine
Accumulation of the false substrate competes with and prevents the movement of the natural substrate. Amphetamine is a better competitor for the NA binding site.
What are two examples of enzymes as drug targets?
Inhibitors and pro-drugs
What is an example of an enzyme inhibitor?
Binds to substrate site (reversibly or irreversibly), or allosteric regulatory site, or disrupt enzyme integrity.
E.g. lisinopril which targets ACE, thus reduces the constrictor angiotensin 2
What are pro-drugs?
They first require conversion by an enzyme to form the active form. e.g. perindopril - ACE inhibitor - that is converted to the active form perindoprilat
What are some non-cellular proteins as drug targets?
Antibodies to inflammatory protein mediators e.g. infliximab for rheumatoid arthritis and inflammatory bowel disease.
e.g. Heparin - anticoagulant - activates anti-thrombin 3 in blood which inhibits the clotting cascade
Who are nucleic acids a target for drug action
Cisplatin is an anti-cancer drug which covalently cross links DNA and prevents replication, transcription and prepare. Therefore promoting cell death.
What is an antacid
Non-protein target for drug action, neutralise gastric acid.
What else can drugs target?
Antibiotics etc used in the prevention or treatment of infections.
