Pharamcology study Flashcards
(34 cards)
Distribution?
Drug moves from blood to tissues (affected by perfusion, membrane crossing ability, protein binding and volume of distribution) /Distribution is the process by which a drug is dispersed throughout the body’s blood and tissues. After a drug enters into systemic circulation by absorption or direct administration, it will pass from vascular spaces to tissues where a drug-receptor interaction will occur, creating the effect of the drug.
how does Metabolism work?
Metabolism is the enzymatic conversion of a drug into a metabolite. This process is crucial for making drugs more easily eliminated from the body by increasing their water solubility, thus facilitating their excretion through urine or bile. (Liver mainly transforms drugs (phase 1= cyp450 oxidation/reduction; Phase 2 = conjugation))
Excretion?
Drug excretion is the removal of drugs from the body, either as a metabolite or unchanged drug. There are many different routes of excretion, mainly the urine and bile. The most important organs for excretion are the kidney and liver.
First pass Metabolism?
drug metabolism at a specific location in the body which leads to a reduction in the concentration of the active drug before it reaches the site of action or systemic circulation. (Drugs like GTN lose potency via liver first-pass effect)
Bio-availability
The ability of a drug to be absorbed and used by the body
Volume of distribution (Vd)
How extensively a drug distributes into body tissues.
Receptors
Where drugs act
Ligand-gated ion channels - Fast (nicotinic)
GPCRs- Seconds (adrenergic, muscarinic)
Enzyme-linked - = hours
Nuclear - Gene transcription (slowest)
Affinity
How strongly a drug binds to a receptor (high affinity means lower dose needed)
efficacy
the ability to trigger a response after binding (maxim response achievable from a drug, measured by E max (the maximal effect)
Potency
Dose needed for maximal effect (higher potency=lower dose needed) (measured by EC50- the concentration that produces 50% of the maximal effect)
Therapeutic index (IT)
Wider=safer (panadol) Narrow=Risky (warfarin)
Agonists
Activates receptors (full, partial)
antagonists
Block receptors (competitive or non-competitive)
Inverse agonists
A compound that binds to and prevents constitutive receptor activity in the absence of an agonist (Produce opposite affects)
2nd pass metabolism (phase 2)
Phase II metabolism, the second stage of drug metabolism in which a drug is conjugated with an endogenous molecule, increasing its water solubility and facilitating excretion. This contrasts with phase I, where a drug is modified, often by enzymes like cytochrome P450s
glucose can be found in different forms, what are they?
Monosaccharides (mono=1) - simplest form of carbohydrates/sugar. cannot be broken down (e.g glucose gel)
Disaccharides (di=2) double sugar formed glucose and frutose.
polysaccardis (poly=multiple) complex carbohydrates.
what is the autonomic nervous system?
the autonomic nervous system controls involuntary bodily functions like, HR, digestion, respiration and pupil size. Its divided into the sympathetic nervous system (fight or flight) and Parasympathetic nervous system (rest and digest)
Receptor effect? (mnemonic ABCD - a, always constricts, B alsways Dilates)
Alpha 1 receptors – affect Arteries (vasoconstriction and smooth muscle contraction)
Alpha 2 - affect brain and peripheral (neurotransmitter realease)
Beta1 – affects heart (increasing heart rate and contractility)
Beta2 – affects Bronchidilation - (widening of airways)
what is somatic nervous system?
somatic nervous system is a component of the peripheral nervous system associated with the voluntary movements of the body via the the use of skeletal muscles. As well as specialized sensory receptors for detecting information within and outside the body
what functions are the somatic nervous system responsible for?
it is responsible for all the functions we are aware of and can consciously influence. this includes movement of arms, legs and other parts of our body. The somatic senses (mechanoreception, thermoreception and pain) are the mechanisms by which sensory information is gathered (are distinct from the special senses. (V,H,T,S,Equilibrium)
what factors affect absorption?
- route of administration: oral drugs go through 1st pass metabolism by the liver whereas IV bypass this process.
- Solubility: lipid-soluble drugs cross membranes more easily
- PH: Drugs better absorbed in certain environments (like acidic drugs - stomach)
- Blood flow: More blood flow increases absorption
- surface area: The small intestine’s large surface area allows for better absorption than the stomach.
- Contact time: Gastrointestinal motility, faster transit time (e.g., in diarrhea) can reduce absorption.
what are the three Types of Glucose in Treatment?
- Glucose gel, is a simple form of pure sugar that is absorbed quickly. (must be able to self administer).
- Glucose 10% - Symptomatic hypoglycaemia (with the inability to self-administer oral glucose). It is a sugar that is the principle energy source for body cells, espically the brain.
- Glucagon - is a hyperglycaemic agent that mobilizes hepatic (liver) glycogen. it is essential a hormone that raises blood glucose levels. we give this when that patient has the inability to self administer oral glucose
what is the Asthma pathway?
- exposed to allergen, cold air or exercise
- immune activates, mast cells release histamine.
- Bronchoconstrication, narrows airways
- inflammation, worsens obstruction
treatment of asthma?
- Sulbutamol: Rapid B2 agonist (causes bronchodilation in the lungs)
- Ipratropium: Anticholingeric (also a brochodilater)