Notes in 1- Drug Therapy

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Published	02/10/2024	When you take a medication:You make sure that the concentration is sufficient to be {{c1::beneficial}} and not {{c1::toxic}}It should be in a therapeu…
Published	02/10/2024	What are the processes behind Drug Therapy?
Published	02/10/2024	What is Clinical Pharmacokinetics?
Published	02/10/2024	What is Pharmacodynamics?
Published	02/10/2024	Why Study Pharmacokinetics (PK) and Pharmacodynamics (PD)?
Published	02/10/2024	{{c1::Pharmacokinetics}} describes what the body does to a drug.
Published	02/10/2024	What are the four basic factors that determine drug pharmacokinetics?
Published	02/10/2024	What is the use of ADME in clinical settings?
Published	02/10/2024	What is absorption?
Published	02/10/2024	Oral Absorption{{c1::Tmax}}→ the time to peak concentration {{c1::Cmax}}→ the peak concentration{{c1::AUC}}→ the area under the drug concentratio…
Published	02/10/2024	What is Tmax?
Published	02/10/2024	What is Cmax?
Published	02/10/2024	What is AUC and how can we use it?
Published	02/10/2024	The {{c1::more rapid}} the rate of absorption, the {{c2::earlier}} the drug concentration peak.
Published	02/10/2024	Increasing dose does not reduce the {{c1::time}} needed to reach peak concentrationbut does {{c1::increase}} the peak concentration. This in…
Published	02/10/2024	Time to Peak Concentration and Cmax vary according to {{c1::route of administration}}
Published	02/10/2024	What is the therapeutic range?
Published	02/10/2024	What is the therapeutic index?
Published	02/10/2024	Describe this image
Published	02/10/2024	When a drug is swallowed: • {{c1::Dissolution}} → breakdown of tablet/capsule • {{c1::Absorption}} → across the lipid membranes in GI system
Published	02/10/2024	[1] What is bioavailability?[2] how do we estimate it?[3] how do we determine the bioavailability of a formulation?
Published	02/10/2024	BioavailabilityIV → 100% bioavailabilityOral → bioavailability decreased
Published	02/10/2024	Why do we have to give a different dose of a drug depending on route?e.g. IV vs Oral
Published	02/10/2024	What are the Factors Affecting Oral Absorption Bioavailability?
Published	02/10/2024	How do drugs transport across membranes?
Published	02/10/2024	What is passive diffusion?
Published	02/10/2024	How do lipid soluble (lipophilic) drugs cross membranes?
Published	02/10/2024	Why don't most drugs completely ionise in water?
Published	02/10/2024	Explain the membrane diffusion between ionised and un-ionised forms of drugs
Published	02/10/2024	How does the gut surface area in the small intestine affect drug absorption?
Published	02/10/2024	How does lipid solubility affect diffusion across membranes?
Published	02/10/2024	What is meant by lipid-water partition coefficient?
Published	02/10/2024	What are the key factors for passive transport?
Published	02/10/2024	What is Filtration/Bulk flow?
Published	02/10/2024	What is the major mechanism through which drugs cross the capillary walls?
Published	02/10/2024	What is active transport?
Published	02/10/2024	How does gut motility affect drug absorption?How does food affect drug absorption?How do illnesses affect drug absorption?
Published	02/10/2024	What is First Pass Metabolism? Where & How does it occur?
Published	02/10/2024	How can we avoid first pass metabolism?
Published	02/10/2024
Published	02/10/2024	What is drug distribution?
Published	02/10/2024	What are the mechanisms behind drug distribution to the tissues?
Published	02/10/2024	What is plasma protein binding and how does it matter in relation to drugs?
Published	02/10/2024	Amount of unbound drug (active drug) can be changed by:    - {{c1::Renal failure}}    - {{c1::Hypoalbuminaemia}}&nb…
Published	02/10/2024	When does protein binding become an important factor to the drug?
Published	02/10/2024	What is the Apparent Volume Of Distribution (Vd) and how is it calculated?
Published	02/10/2024	• The greater the {{c1::Vd}} the greater the ability of the drug to diffuse into and through lipid membranes.In theory the {{c1::Vd}} should…
Published	02/10/2024	What is clearance?
Published	02/10/2024	Renal vs Hepatic clearanceWhat are they dependant upon?
Published	02/10/2024	What is half-life t1/2 of a drug?What is it dependant upon?
Published	02/10/2024	Why does prolongation of a drug's half life cause toxicity?
Published	02/10/2024	What does this equation represent?  t1/2 = 0.693 x Vd/Cl
Published	02/10/2024	• To have a therapeutic benefit most drugs needed to be given {{c1::chronically}}. • Plasma levels of a drug take many doses before they {{c1::stabili…
Published	02/10/2024	Steady State Concentration & Chronic DosingExplain this diagram
Published	02/10/2024	What are the individual factors that can lead to an increase in the half life of a drug resulting in increased blood drug levels and toxicity?
Published	02/10/2024	What is Drug Elimination?
Published	02/10/2024	Why is renal damage an important factor in causing drug toxicity?
Published	02/10/2024	What is the glomerular filtration?How does it play a role in toxicity when impaired?
Published	02/10/2024	What is Active Tubular Secretion?
Published	02/10/2024	What is Passive Tubular Reabsorption?
Published	02/10/2024	What is the role of Biliary secretion?
Published	02/10/2024	What's the role of drug conjugation?Where does it occur?
Published	02/10/2024	Why does damage to the liver lead to toxicity?
Published	02/10/2024	Drugs that Undergo Enterohepatic Recirculation
Published	02/10/2024	Chemical properties of the drug determine where it reaches (volume of distribution) – {{c1::lipid solubility}}, {{c1::ionisation}}.
Published	02/10/2024	{{c1::Clearance}} and {{c1::distribution}} determine the drug half life in the body and therefore {{c2::dose}} and {{c2::frequency}}.
Published	02/10/2024
Published	02/10/2024	What is Drug Metabolism?How does it happen?Where does it happen?
Published	02/10/2024	Some drugs need activation by metabolism ({{c1::prodrugs}}) or form active metabolites following metabolism.• include – codeine, ramipril, simvastatin
Published	02/10/2024	What are the effects of Drug Metabolism?
Published	02/10/2024	{{c1::Prodrugs}} are drugs that increase in activity, more active metabolites, following drug metabolism.
Published	02/10/2024	Enzymes have a wide substrate specificity and individual drugs can be metabolised by more than one.Enzyme induction can lead to increased metabolism o…
Published	02/10/2024	{{c1::Metabolism}} is divided into two phases:
Published	02/10/2024	{{c1::Phase I metabolism}} is a phase of metabolism that involves exposing or introducing a drug to polar groups.
Published	02/10/2024	What is Phase I metabolism?
Published	02/10/2024	Isoforms of cytochrome P-450:[1] {{c1::CYP3A4}}→ major constitutive enzyme in human liver→ also found in the gut and is responsible for the pre-system…
Published	02/10/2024	Why are 5-10% of the population fully/partially immune to the analgesic actions of codeine?
Published	02/10/2024	Why do smokers require a higher dose of theophylline than non-smokers?
Published	02/10/2024	What is Phase 2 Metabolism?
Published	02/10/2024	Common Pattern of Drug MetabolismUncommon Pattern of Drug Metabolism
Published	02/10/2024	Factors Which Affect Metabolism:• Other drugs/herbals/natural substances • Genetics • Hepatic blood flow • Liver disease • Age • Sex • Ethnicity • Pre…
Published	02/10/2024	What is enzyme induction?
Published	02/10/2024	The most common enzyme inducers include {{c1::alcohol}} and {{c1::smoking}}. • Process may take weeks
Published	02/10/2024	What is Enzyme Inhibition in relation to metabolising enzymes?
Published	02/10/2024	How does pharmacogenetics affect treatment?
Published	02/10/2024	Genetic Polymorphisms - CYP2D6 Polymorphisms
Published	02/10/2024	Genetic Polymorphisms - CYP2C9 Polymorphisms
Published	02/10/2024	Genetic Polymorphisms - CYP2C 19 Polymorphisms
Published	02/10/2024	Other Enzymes Which Exhibit Genetic Variation
Published	02/10/2024	How does age determine drug metabolic activity?
Published	02/10/2024	How does gender affect drug metabolic activity?
Published	02/10/2024
Published	02/10/2024	A {{c1::drug interaction}} is defined as the modification of a drug's effect by prior or concomitant administration of another Drug, Herb, Foodstuff, …
Published	02/10/2024	Types of drug interactionsØ {{c1::Drug}} - drug interactions (DDI). Ø {{c1::Herb}} - drug interactions. Ø {{c1::Food}} - drug interactions. Ø {{c1::Dr…
Published	02/10/2024	Factors (precipitants) which modify drug action include:Ø {{c1::drugs}} Ø {{c1::food}} Ø {{c1::smoking}} Ø {{c1::alcohol}} Ø {{c1::herbs}}
Published	02/10/2024	Why are drug interactions generally avoided, and when are they commonly used?
Published	02/10/2024	DDIs are the {{c1::2nd}} most common cause of preventable ADRs in primary careDetrimental interactions affect: Ø 2.2 - 30% of patients in hospital Ø 9…
Published	02/10/2024	Clinically important adverse effects following an interaction occur only in the presence of {{c1::specific risk factors}}.
Published	02/10/2024	Drugs Involved With Serious Interactions
Published	02/10/2024	What does it mean if an object drug is potent with a narrow therapeutic index?
Published	02/10/2024	Foods Interacting with Warfarin
Published	02/10/2024	What patients are more susceptible to drug-drug interactions?
Published	02/10/2024	As the number of {{c1::prescribed drugs}} increase, the number of {{c1::drug-drug interactions}} increase.
Published	02/10/2024	Mechanisms of Drug Interactions:[1] {{c1::Pharmaceutical}} interactions [2] {{c1::Pharmacokinetic}} interactions - Absorption (chelation, gut motility…
Published	02/10/2024	What are the mechanisms of drug interactions?
Published	02/10/2024	Pharmacokinetics drug-drug interactionsMechanisms of absorption interactions: § Formation of {{c1::insoluble}} complexes § Altered {{c1::pH}} § Altere…
Published	02/10/2024	Why is the interaction of drugs in the GI tract complex?
Published	02/10/2024	What's the importance of delayed absorption?
Published	02/10/2024	How can delayed absorption, which occurs in most interactions, be avoided?
Published	02/10/2024	How do changes in pH affect absorption in the GI tract?
Published	02/10/2024	How do changes in GI bacterial flora affect absorption in the GI tract?
Published	02/10/2024	How does GI motility affect absorption in the GI tract?Ø Most oral medicines are absorbed in the small intestine
Published	02/10/2024	After absorption, drugs are distributed to the site of action, how does this happen?How can drug-drug interactions affect distribution?
Published	02/10/2024	{{c1::Protein-binding displacement}} occurs when there is a reduction in the plasma protein binding of a drug caused by the presence of another drug.&…
Published	02/10/2024	What does protein-binding displacement result in?How may patients be protected from protein binding displacement?
Published	02/10/2024	Drugs with Protein Binding >95%
Published	02/10/2024	What is drug metabolism and how is it affected by drug interactions?
Published	02/10/2024	Enzyme {{c1::induction}} → takes 2-3 weeks for effects to be seenØ depends on age, disease, genetics and concurrent drug therapyEnzyme {{c1::inhibitio…
Published	02/10/2024	Rifampicin increase metabolism of Ciclosporin by inducing CYP3A4→ prevents transplant rejection
Published	02/10/2024	St John's wort increase metabolism of ciclosporin by inducing CYP3A4
Published	02/10/2024	What is drug elimination and how is it affected by drug interactions?
Published	02/10/2024	When do pharmacodynamics interactions occur?Reminder: Pharmacodynamic is what the drug does to the body
Published	02/10/2024	Types of Pharmacodynamic Interactions:Ø {{c1::Direct}} Ø {{c1::Indirect}} Ø {{c1::Antagonistic}}e.g. using both atenolol and salbutamol→ atenolol caus…
Published	02/10/2024	Pharmacodynamic Interactions→ e.g. of Indirect agonism
Published	02/10/2024	Pharmacodynamic Interactions→ e.g. of Indirect Antagonism [1] NSAIDs increase blood pressure (opposite in what is needed in antihypertensive…
Published	02/10/2024
Published	02/10/2024	{{c1::Adverse Drug Reactions}} are:→ Any response to a drug which is noxious, unintended and occurs at doses used in man for prophylaxis, diagnosis or…
Published	02/10/2024	Epidemiology of ADRs
Published	02/10/2024	{{c1::Medication errors}} - is any error in the prescribing, dispensing, or administration of a drug, irrespective of whether it leads to adverse cons…
Published	02/10/2024	Adverse Drug Reactions - Classification of Onset:[1] {{c1::Acute}}» within 60 minutes » bronchoconstriction, anaphylaxis[2] {{c1::Sub-acute}}» 1 to 24…
Published	02/10/2024	Adverse Drug Reactions - Classification of Severity:[1] {{c1::Mild}} » bothersome but requires no change in therapy   e.g. Metallic taste with me…
Published	02/10/2024	Most Commonly Used Classification of ADRs• ADRs are divided into:   Type A  {{c1::Augmented}}   Type B  {{c1::Bizarre}}   Typ…
Published	02/10/2024	Predisposing Factors for Adverse Drug Reactions:[1] {{c1::Multiple Drug Therapy}} → Incidence of ADRs increase exponentially with the number of medica…
Published	02/10/2024	{{c1::Type A}} adverse drug reactions are characterized by normal but augmented response to the pharmacological actions of a drug.• Entirely pred…
Published	02/10/2024	What are Type A  ADRs?
Published	02/10/2024	Why do Type A ADRs occur?
Published	02/10/2024	How are Type A ADRs and Pharmacokinetic variation (ADME) related?
Published	02/10/2024	{{c1::Liver}} and {{c1::renal}} disease are particularly important to consider when drugs have a narrow therapeutic index
Published	02/10/2024	How are Type A ADRs and Pharmacogenetic variation related?
Published	02/10/2024	How are Type A ADRs and diseases related?
Published	02/10/2024	How are Type A ADRs and Pharmacodynamic variation related?
Published	02/10/2024	{{c1::Type B}} ADRs are:• Bizarre - Unpredictable - Rare • Cause serious illness or death • May be unidentified for months or years • Unrelated to the…
Published	02/10/2024	Important factors in Type B ADRs:More common with:[1] {{c1::Macromolecules}} - proteins - vaccines - polypeptides [2] Patients with history of {{c1::a…
Published	02/10/2024	Mechanisms underlying Type B ADRs:[1] {{c1::Idiosyncratic}}   • Inherent abnormal response to a drug   • Due to genetic abnormality such as …
Published	02/10/2024	Genetic abnormalities may lead to abnormal and unpredictable responses to drugs:[1] {{c1::Enzyme}} Abnormalitye.g. Erythrocyte glucose 6-pho…
Published	02/10/2024	{{c1::Direct}} pharmacodynamic interaction: in which drugs having similar or opposing pharmacological effects are used concurrently.{{c1::Indirec…
Published	02/10/2024	{{c1::Drug Allergy–Hypersensitivity Reactions}} are reactions that occur due to antigen-antibody interaction which leads to a subsequent antigen-antib…
Published	02/10/2024	{{c1::Type C}} ADRs are related to both the duration and dose of a treatment, and does not occur within a single dose.→ Chronic/Long Term Effects→&nbs…
Published	02/10/2024	{{c1::Type D}} ADRs are characterized by adverse effects that occur a long time after treatment.→ Delayed Effectse.g.Lymphomas are increased in freque…
Published	02/10/2024	Why should all drugs be avoided during pregnancies?esp. teratogenic drugs
Published	02/10/2024	{{c1::Type E}} ADRs characterized by adverse effects which occur when a drug treatment is suddenly stopped especially following long-term use.→ End of…
Published	02/10/2024	{{c1::Rebound Phenomena}} occurs when a drug is suddenly withdrawn• Alcohol • Benzodiazepines • Opiates • Beta-blockers • Corticosteroids • Antidepres…
Published	02/10/2024	{{c1::Type F}} ADRs are characterized by failure of therapy.• Common • Dose related (too low dose) • Frequently caused by drug interactions e.g. …
Published	02/10/2024	Diagnosing ADRs
Published	02/10/2024	Who is most at risk of ADRs?
Published	02/10/2024	The more medications in a regimen, the greater likelihood of an {{c1::ADR}}→ due to drug-drug interaction increase
Published	02/10/2024	Surveillance methods for ADRs{{c1::Yellow}}-card system→ Online reports made for all medicines including vaccines, blood factors and immunoglobul…
Published	02/10/2024	How do we report an ADR?What should we report?{{c1::Through the Yellow-Card system• Online reports made for all medicines including vaccines, blo…
Published	02/10/2024
Published	02/10/2024	Summary of Adverse Drug Reactions (ADRs) -1
Published	02/10/2024	Summary of Adverse Drug Reactions (ADRs) -2
Published	02/10/2024	Drug Delivery Formulations:• Tablets or capsules  - regular, modified release, prodrugs, enteric coated • Solutions or suspensions • Ointments an…
Published	02/10/2024	A drug delivery system can be formulated (constructed) to allow {{c1::immediate}} or {{c1::delayed}} onset.i.e. 24 hour duration of action; or to avoi…
Published	02/10/2024	What are the factors that determine the drug delivery system we use?
Published	02/10/2024	How do we choose a dosage regime?
Published	02/10/2024	{{c1::Oral medication}} is the most frequently used dosage route• tablets, capsules, solutions and suspensions, and modified release tablets are in co…
Published	02/10/2024	{{c1::Solutions and Suspensions}} are delivery systems used to administer drugs to the young, elderly and patients who can’t swallow tablets or capsul…
Published	02/10/2024	{{c1::Suspensions}} are dispersions of coarse drug particles in a liquid phase.→ dose can be contained in a small volume→ Good for drugs which are ins…
Published	02/10/2024	{{c1::Tablets and Capsules}} are the most commonly used formulation.Rate limiting step in absorption → dissolution or tablet/capsule breakdownDistinct…
Published	02/10/2024	Why are some tablets enteric coated?'Modified Tablets-Enteric Coated'
Published	02/10/2024	{{c1::Prolonged/Delayed release formulations}} are forumlations that contain sufficient drug to dose for a 24 h – 4 year period.They are useful becaus…
Published	02/10/2024	How can the time course for a drug in the body be prolonged?
Published	02/10/2024	{{c1::Prodrugs}} are synthesised inactive derivatives of an active drug which need to be metabolically activated after administration.The advantages o…
Published	02/10/2024	{{c1::Buccal and Sublingual Administration}} is the ideal method of administration for drugswhich have extensive pre-systemic or first pass metabolism…
Published	02/10/2024	{{c1::Rectal Route}}: mn wraDrugs may be administered rectally: - to treat local conditions such as proctitis - to achieve systemic absorption (benzo…
Published	02/10/2024	{{c1::Vaginal route}} uses pessaries and creams, only in women, and only for treatment of local disease.
Published	02/10/2024	Injection based drug delivery system:• {{c1::Intravenous}} • {{c1::Intramuscular}} • {{c1::Subcutaneous}}
Published	02/10/2024	Why are some drugs given intravenously?
Published	02/10/2024	Why are IV formulations infused within a recommended time?i.e. bolus, 5 mins 30 mins or continuous
Published	02/10/2024	{{c1::Intramuscular Injection}} is an injection of the drug is given into the muscle massThe drug may be insoluble or formulated in an oil base → Allo…
Published	02/10/2024	{{c1::Subcutaneous Injection}} is an injection into fat layer, which bypasses the need for venous access.• Used for insulin, heparin and narcotic anal…
Published	02/10/2024	{{c1::Dermojet}} is a subcutaneous needleless injection used for mass inoculation.{{c1::Pellet implantation}} is the process when the drug a…
Published	02/10/2024	Why are some drugs insoluble or formulated in an oil base?
Published	02/10/2024	{{c1::Percutaneous}} administration uses creams, ointments and skin patches.Achieve a local effect i.e steroids or a systemic effect i.e HRT or nitrog…
Published	02/10/2024	{{c1::Skin Patches}} allow the release of a drug from a reservoir into the skin and then into the systemic circulationPossible to obtain controlled, s…
Published	02/10/2024	{{c1::Transdermal}} Drug Delivery System→ Adhesive patches containing the drug are applied on the skin → The drug crosses the skin surface by diffusio…
Published	02/10/2024	{{c1::Inhalation}} is a route used to deliver drugs directly to the lung for: a local effect i.e. salbutamol a systemic effect i.e. inhaled …
Published	02/10/2024	Advantages of Inhalation:• Drug delivered directly to site of action • Rapid effect • Small doses used • Little systemic absorption • Reduced adverse …
Published	02/10/2024	Carrier based drug delivery system
Published	02/10/2024	{{c1::Monoclonal antibody}} (mAbs): is an antibody made by cloning a unique white blood cell.All subsequent antibodies derived thi…
Published	02/10/2024	{{c1::Antibody Drug Conjugates}} are drugs that consist of a mAb attached to a biologically active drugwith a linker which is stable in the circulatio…
Published	02/10/2024	Why are some drugs pegylated?i.e. putting them inside a liposomeWhat is unique about Pegylated liposomal doxorubicin (PLD)?
Published	02/10/2024	{{c1::Nanoparticle}} based drug deliveryUsing nanotechnology the drug can be targeted to a precise tissue location which means we can use a lower dose…
Published	02/10/2024	How does gene therapy work?
Published	02/10/2024	Why is gene therapy risky?
Published	02/10/2024	{{c1::Immunotherapy-CAR T Cell}} is a type of therapy that collects and uses patients' own immune cells to treat their cancerSeparate out T cells. The…
Published	02/10/2024	Color and Drug relation
Published	02/10/2024	What are medication and prescribing errors?
Published	02/10/2024	The prevalence of medication and prescribing errors→ Medication errors are the single most preventable cause of patient harm leading to between 44,000…
Published	02/10/2024	Where do medication errors mostly occur within the NHS structure?
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