4 Drugs Flashcards
(26 cards)
What is an agonist?
- substance which initiates a physiological response when combined with a receptor (normally correcting something that has been lost)
What is a full agonist?
- bind to and activates a receptor, producing the maximum possible response that the tissue being targeted is capable of giving
What is a partial agonist?
- drugs that bind to and activate a given receptor, but have only partially produced the desired effect
What are the 2 types of agonists?
- partial and full agonists
How do agonists work?
- steroid hormone enters cell
- binds to receptor protein
- hormone receptor complex forms in nucleus
- hormone receptor complex binds to specific gene sequences in DNA
- genes are transcribed into mRNA which leaves nucleus
- ribosomes translate mRNA into protein
What is the protein made by an agonist used for?
- protein made is essential to the cells function in some way
What does levothyroxine treat?
- hypothyroidism
Which hormone is deficient if dealing with hypothyroidism?
- Thyroxine (T4)
What type of drug is levothyroxine?
- agonist
Explain levothyroxine molecular basis of action
- levothyroxine binds to natural carrier protein in the blood
- once it enters the cell it is metabolised into its active form L-triiodothyronine (T3)
- T3 binds to thyroid receptor proteins in the cell nucleus
- T3 receptor complex binds to specific areas of DNA and activates specific genes to make proteins
What are antagonists?
- occupies receptors but do not activate them, block receptor activation by agonists
What are the 2 types of antagonists?
- competitive and irreversible
What are competitive antagonists?
- slow down process by temporarily blocking a site or receptor
What are irreversible antagonists?
- stop a reaction permanently blocking a site or receptor
What type of drugs are beta blockers?
- competitive antagonists
Explain the molecular basis of action of beta blockers
- temporarily block receptor sites (beta adrenoceptors) for adrenaline and noradrenaline (hormonal neurotransmitters found in nervous system)
- slows down but do not stop the impulse of the heart
- slows down the rate and force of the heart muscle contraction is reduced, reducing blood pressure
What are beta blockers prescribed for?
- high blood pressure
- angina
- atrial fibrillation
- heart failure
What is omeprazole prescribed for?
- Gastroesophageal reflux disease
What is omeprazole?
- proton pump inhibitor
Where are proton pumps found?
- stomach lining
What do proton pumps secrete?
- acid
What are the protons being pumped called?
- H+ ions
What type of drug is omeprazole?
- irreversible non competitive antagonist
Explain the molecular basis of action of omeprazole
- Proton pumps use active transport to move protons (H+) against a concentration gradient using ATP as energy into the lumen of the stomach
- Omeprazole, a proton pump inhibitor, irreversibly binds to the ATP binding site- ATP cannot bind as protons move against the concentration gradient
