clinical pharmacology Flashcards
Define pharmacodynamics
What the drug does to the body
Define pharmacokinetics
What the body does to the drug
What is clinical pharmacology
the study of clinical effectsof drugs on patients
What interacting considerations do we need to be aware of when prescribing drugs
Name the different types of molecules drugs can target (+ examples)
Receptors (e.g. benzodiazepines - GABA receptor agonists).
Ion channels (e.g. verapamil -calcium channel blockers).
Enzymes (e.g., ACE inhibitors).
Structural proteins (e.g. Taxol - Tubulin agonist)
Carrier molecules (e.g. digoxin)
DNA (e.g. Doxorubicin - anticancer agents).
What is a dose response curve
Draw a dose response curve for a partial vs full agonist
Fentanyl is full agonist because it reaches maximum response (analgesia)
So is morphine but its less potent (need more for same response)
Partial agonist: has an analgesic effect but wont elicit full response
Don’t use fentanyl right away because it might be really potent but can also have toxic effect
Define potency
amount of drug required to produce 50% of its maximal effects (ED50). Used to compare drugs within a chemical class
Define efficacy
the maximum therapeutic response that a drug can produce (example: morphine vs buprenorphine)
Draw a graph for this
define specificity
capacity of a drug to cause a particular action in a population
Example: a drug with absolute specificity of action might decrease or increase the specific function of a given target. It must do either, but not both.
Define selectivity
relates to a drugs ability to target only a selective population i.e. cell/tissue/ signalling pathway, protein etc in preference to others.
Example: Atenolol is a B1-selective adrenoreceptor antagonist, while propranolol is a non-selective B-antagonist
What is the therapeutic index (TI)?
The therapeutic index is the difference between toxic and therapeutic doses
A high TI indicates a safer drug, while a low TI requires careful dosing.
What is drug antagonism and what are the types?
Antagonism occurs when a drug inhibits the effect of an agonist.
- Competitive antagonism:
- antagonist competes with agonist for same receptor binding site.
- Can be overcome by increasing agonist concentration. - Non-competitive antagonism:
- antagonist binds to different site or inhibits post-binding pathways.
- Can’t be overcome by increasing agonist concentration.
How does the presence of a competitive antagonist affect drug receptor curves?
dose-response curve shifts to the right.
Agonist potency decreases, requiring a higher concentration to achieve the same effect.
The maximum efficacy of the agonist remains achievable, provided a sufficient concentration is administered.
Key example: Methadone vs. Naloxone, where Naloxone acts as a competitive antagonist.
What is the action of drugs on enzymes
Bind to catalytic site
Inhibit normal reaction, thus
Decreased production of undesired product
What is tachyphylaxis and why does it occur
Loss of target sensitivity
effect of drug can decrease when given continuously or repeatedly due to:
- Change in receptors (become resistant to drug stimulation/conformational changes)
- Loss of receptor number
- Exhaustion of mediators
- Increased metabolic degradation of drug
- Physiological adaptation (crosstalk between body systems, one takes over)
- Drug transporters (active extrusion of the drug)
What is the purpose of The Veterinary Medicines Regulations 2013
How is veterinary medicine regulated?
Through data assessment, certification, prescribing/dispensing, inspections, and post-marketing surveillance for quality, safety, and efficacy.
Name the categories of veterinary medicines
Prescription-only medicine – Veterinary (POM-V).
Prescription-only medicine – VPS (Vet, Pharmacist, SQP).
Non-food animal – VPS (NFA-VPS).
AVM-GSL (General Sales List).
Small Animal Exemption Scheme (SAES).
What is a suitably qualified person?
SQP works according to a VMD Code of Practice
Training covers legislation, basic anatomy & physiology & basic disease challenges plus species modules: farm animal; equine; companion animal & avian leading to different qualification
To supply medicines SQP must have passed relevant species module & base exam
What is the role of the Veterinary Medicines Directorate (VMD)?
To regulate veterinary medicines, ensuring safe use, manufacturing, and provision of reliable information.
What is the difference between POM-V & POM-VPS?
POM-V:
- Requires a clinical assessment by a vet
- for high-risk medicines needing professional control.
- only prescribed by veterinary surgeon
POM-VPS:
- Can be prescribed by vets, pharmacists, or SQPs
- without clinical assessment
- for endemic disease prevention.
When is a medicine classified as a POM-V?
It requires strict limitation on its use for specific safety reasons
It requires specialized knowledge of veterinary surgeon for its use/application
It has narrow safety margin requiring above average care in its use
It is government policy to demand professional control at a high level (for example, antimicrobials and Controlled Drugs).
What are Non-Food Animal VPS (NFA-VPS) medicines, and how are they prescribed and supplied?
Purpose:
- For companion animals (excluding horses) to prevent or limit effects of endemic disease.
Prescribing and Supply:
- Supplied by vet, pharmacist, or SQP.
- No clinical assessment required.
- supplier must ensure person administering medicine is competent & intends to use it for authorized purpose.
Requirements:
- Minimum amount needed for treatment should be supplied.
- Risks to user, animal, or environment should be mitigated through advice & training.
What are the other categories of drugs
Controlled drugs
Specified feed additive
What is the Small Animal Exemption Scheme (SAES), and how does it work?
Purpose:
- Covers medicines for specific pet species such as aquarium fish, cage birds, ferrets, homing pigeons, rabbits, small rodents, & terrarium animals.
Exemptions:
- These medicines are exempt from requiring marketing authorization.
- They are not required to prove safety, quality, or efficacy.
Standards:
- Must still be manufactured to same quality standards as authorized medicines.
- Subject to pharmacovigilance reporting.
Supply and Sale:
- Treated similarly to AVM-GSL (General Sales List) medicines.
Define prescribing
“any prescription for a veterinary medicinal product issued by a professional person qualified to do so in accordance with applicable national law.”
What factors must a prescriber consider when deciding which product to supply?
- circumstances of animals being treated.
- available authorized veterinary medicinal products.
- need for responsible use of medicines.
- Prescribing minimum amount necessary for treatment.
- competence & abilities of person administering medicine.
- Any available animal health plan.
What are the key requirements for records, storage, and disposal of medicines?
Records kept for 5 years.
Include details of supply, batch, and recipient.
Safe storage (correct temperature, no contamination).
Proper disposal to prevent misuse or environmental harm.
