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HOME GROUP 3 (PHC461), Caffeine, Caffeine molecules closely resemble the…

- - - - Caffeine side effects can make asthma symptoms worse for some people.
      - Caffeine, over time may increase the stress hormone in your body, which could actually induce an asthma attack in some people.
        
        Stress hormones norepinephrine and epinephrine produced by adrenal glands that causes consumer to feel jumpy.
      - Asthmatic patients need to consume high amount of caffeine to relief their asthma which may lead to serious side effect.
    - - Clinical studies have shown that caffeine is a weak bronchodilator
        
        Improves lung function for two to four hours after it is consumed.
        
        Definition of bronchodilator: drug that causes the widening of bronchi. E.g.: Any drugs taken by inhalation for the alleviation of asthma.
        
        Caffeine is similar to bronchodilator called Theophylline
        
        What is Theophylline?
        
        Theophylline is a bronchodilator drug that is taken to open up the airways in the lungs and therefore relieve the symptoms of asthma such as wheezing, coughing and breathlessness.
      - Drinking coffee two to three times a day can prevent asthma attacks. This is because caffeine in coffee helps keeping airways open by widening the bronchi
  - - - During headache, blood vessels swell causing an increase in blood flow around the brain. This increase blood flow pressure surrounding nerves, which send pain messages to the brain. The vasoconstrictive properties of caffeine narrow the blood vessels, thus the blood flow is restricted and pain can be alleviated.
    - - How?
        
        Caffeine which is used as an ingredient in pain reliever will make it 40% more effective.
    - - Paracetamol
        
        Caffeine can also enhance the painkilling effect of paracetamol. For example, Panadol extra advance tablets, a type of paracetamol, have been specially formulated to allow the paracetamol to be absorbed into the bloodstream faster than standard paracetamol tablets or capsules.
      - Common OTC drugs containing caffeine are Vivarin, Anacin tablets, and Excedrin Caplets.
  - - - Drug: Ephedrine
        
        Both ephedrine and caffeine are stimulant drugs. Hence, consuming caffeine along with ephedrine might cause too much stimulation and sometimes serious side effects and heart problems.
      - Drug: Fluvoxamine
        
        Affects the elimination of caffeine
        
        Fluvoxamine is an antidepressant that belongs to the group of selective serotonin re-uptake inhibitors (SSRI) used to treat social anxiety disorder (social phobia) or obsessive-compulsive disorders. Administration of caffeine and fluvoxamine impairs the clearance of caffeine and prolongs caffeine elimination half-life, which is attributable to inhibition of CYP1A2 by fluvoxamine
      - Drug: escitalopram oxalate
        
        Absorption is affected by caffeine
        
        The absorption of escitalopram oxalate decrease by the formation of complexes between the drug and caffeine. This complex formation reduced the bioavailability of escitalopram oxalate tablets by decreasing their dissolution.
      - Drug: Aspirin
        
        Absorption is affected by caffeine
        
        The ingestion of coffee with aspirin can increase the rate of aspirin absorption significantly. The mechanism by which caffeine affects the rate of absorption is by enhancing the gastric acid secretion. The resulting reduction in gastric pH may increase the unionized form of drugs and thus facilitates its absorption.
- - - - This will cause the increasing of hormone released from the pituitary gland that responsible for the production of adrenaline and epinephrine
        
        Adrenaline affects the increased of heart beats and gave the feeling of excited
    - - It allows the dopamine receptor to be fully utilized a higher level
        
        It makes our brain to be more sensitive to dopamine
        
        Dopamine is a neurotransmitter that activates the pleasure centers in certain parts of our brain
        
        But too much dopamine in the brain can be dangerous - causing aggressive and competitive behaviours as well as ADHD and addiction
  - - - The nerve cell activity speeds up, and brain blood vessels constrict.
        
        The adenosine is blocked from attaching to them and cannot cause the typical response of sleepiness.
        
        Adenosine locks with the A1 receptor, it promotes muscle relaxation and sleepiness, which is why people get tired as the day progresses.
        
        By blocking adenosine A2A receptor, caffeine will promote wakefulness by enhancing the release of mood improving neurotransmitter (dopamine)
        
        Adrenalines are released from the pituitary gland due to activation numerous neural circuits after caffeine bind to the adenosime receptor
        
        Adrenaline is known as fight or flight hormone
        
        1 more item...
  - - - Can diffuse into membrane easily
    - - Metabolize by liver to its isomer - theophylline, theobromine, and paraxanthine
        
        The metabolites entered the systemic circulation and absorbed into membrane
        
        easily pass through blood brain barrier (BBB) via diffusion
        
        Paraxanthine
        
        84% of caffeine
        
        A CNS stimulatant
        
        Stimulate fat releases for muscle fuel
        
        Increase the release of epinephrine
        
        Provide energizing effect
        
        Theobromine
        
        12% of caffeine
        
        Stimulate the increasing of oxygen and nutrient flow to brain
        
        Stimulate the dilation of blood vessel
        
        Increases the volume of urine produced
        
        Theophylline
        
        4% of caffeine
        
        Stimulate the heart rates
        
        Stimulates the increasing of the forces of heart contraction
    - - Can bind to adenosine receptor on the cell surface of brain
        
        The binding of caffeine to adenosine receptor blocked adenosine from binding
- - - - The potency of a substance can be obtained from a dose-response relationship. The potency of caffeine can be defined as a measure of the amount of caffeine necessary to produce an effect of a given magnitude. In other words, is the concentration of caffeine producing an effect that is 50 percent of the maximum is used to determine potency and is referred to as the EC50.
        
        Both potency and efficacy can be determined from a graded dose-response curve
        
        For instance, the more potent the medication, require less concentration to generate a response, so the more potent drug will be on the left side.
        
        It is easier to compare the efficacy and potency by the graded dose curve.
      - Potency is related to affinity
        Affinity is the primary determinant of drug potency. It means that when the affinity of the drug to bind to the receptor increase, then the potency of the drug also increases. That means for potency, if the drug's affinity for the receptor is poor and it provides less than 50% of its maximum action, the medicine is called impotent.
    - - Efficacy in this trigger means the ability of caffeine to elicit a response when it interacts with a receptor. Efficacy is dependent on the number of drug-receptor complexes formed and the efficiency of the coupling of receptor activation to cellular response.
        
        Drug with greater efficacy is more therapeutically beneficial than one that is more potent.
        
        Efficacy is also dependent on the efficiency of the coupling of receptor activation to cellular responses. If the caffeine acts as an irreversible competitive antagonism, the competition of caffeine-adenosine will cause a downward shift of the maximum efficacy.
    - - Maximum efficacy remains unchanged when the caffeine present acts as a competitive antagonist and the adenosine potency decrease in the presence of caffeine.
      - When it encounters adenosine, it competes with adenosine for the active binding site on the same receptor.
      - The potency of caffeine showed that blockade of the actions of adenosine is achieved at considerably lower concentrations.
  - - - Firstly, the ligand, which is an external signalling molecule, will bind to the GPCR and activates G protein
        
        Then the dissociation of G protein occurs causes a conformational change of receptor.
        
        The alpha subunit is actually going to exchange GDP for GTP during this conformational change.
        
        After GTP bound, the alpha subunit dissociates from the beta-gamma complex and regulates target proteins.
        
        The target protein then relay signal via second messenger.
        
        Diagram
    - - G-protein coupled receptors(GPCR) is seven-transmembrane receptors
        
        Called heptahelical receptor
        
        Contain seven transmembrane receptors
        
        They pass through the cell membrane seven times.
    - - In the cell membrane
  - - - What is an antagonist receptor?
        
        An inhibitor of receptor activity.
        
        Antagonist medicines prevent receptor proteins from functioning normally
        
        It works opposite to the agonist.
      - What would they do?
        
        A type of receptor ligand or medication that binds to and inhibits a receptor rather than activating it like an agonist, therefore inhibiting or dampening a biological response.
        
        In consequence, of this, antagonists will block the original agonist from binding to the receptors and make them unable to activate the receptor.
        
        From other points of view, the antagonist for a receptor means that the drug occupies the receptor but do not activate them.
    - - Competitive antagonism, non-competitive antagonism, chemical antagonism, pharmacokinetic antagonism and physiological antagonism.
      - In this case, what is the type of antagonist involve between adenosine and caffeine?
        
        It is a reversible competitive antagonism.
        
        This type of antagonist binds reversibly (can be displaced) with the same binding site as the agonist but without activating them.
        
        There is often similarity between antagonist and agonist that enable them to compete each other and to bind to the same receptor.
        
        In this case, caffeine is the competitive antagonist while adenosine is a full agonist.
- - - - Caffeine can penetrate and enter blood brain barrier
      - Become dependent to caffeine as there are many receptors that need to be bind to caffeine to keep us energized.

ANIS IZZATI BINTI ABU MANSOR (2020473754)

NUR AMIRAH HUSNA BINTI MOHD HALIMI (2020498984)