Pharmacy Stage 1 January

FACULTY OF SCIENCE & ENGINEERING SCHOOL OF PHARMACY EXAMINATION PAPER ___________________________________________________________________ Module Code : 4PY019 Module Title : Pharmacy Stage 1 Date : January 2023 Examiners : MJ Palframan, A Armesilla, A Karakoula, Z. Elsaid, M Hewitt, S. Anderson, W. Kaialy C. Dewsbury Time Allowed : 1 Hour ___________________________________________________________________ INSTRUCTIONS TO CANDIDATES  Answer ALL Questions. Answer each question in a separate answer booklet. MATERIALS REQUIRED  You may use a scientific calculator. This must not be programmable.  Periodic Table (is located at the end of the examination paper) ---------------------------------------------------------------------------------------------------------------- Question 1 You are the community pharmacist on duty on when a patient walks into the pharmacy. She is distressed because she has driven 300 miles to help look after her elderly sister, whom she is staying with for the next week, but has left her own prescribed medication at home. She does not have a prescription. She states that she usually has a salbutamol 100 micrograms/dose inhaler (POM) at a dose of TWO puffs when required. She is worried because she has asthma and uses this when needed for breathlessness. She asks whether you can help her? Part A What action would you take? Give a detailed explanation of your answer including: a) What information you need to know to help the patient b) The law relating to this 5 marks 1 mark c) What records, if any, you would need to make and where you would make them 4 marks Part B Salbutamol exerts its action by binding to a cell surface receptor located in the smooth muscle cells of the bronchioles. Answer the following short questions regarding salbutamol. a. What is the difference between agonist and antagonist? 2 mark b. Does salbutamol act as an agonist or an antagonist on this receptor? What is the physiological ligand that binds to this receptor? 2 mark c. Describe the pharmacological steps involved in G-Protein Coupled Receptors binding and signalling activated by binding of salbutamol to the receptor? 5 mark d. What is the effect of salbutamol on the respiratory system? 1 mark Part C Given the structure of salbutamol, shown below, Draw the Newman projection as viewed down the indicated arrow. 2 marks Part D In severe bronchospasm, salbutamol could also be given via intravenous injection or infusion. Assuming first order kinetics, a half-life of 5 hours, and an initial dose of 250 micrograms given via intravenous administration, answer the following questions (show your working out): For the following questions you could consult the pharmacokinetic formula below: kel = 0.693 DOSE = C0 x Vd Clp = F x DOSE AUCoral t0.5 Clp = kel x Vd F = AUCoral AUCi.v. AUC0-¥ = DOSE Clp AUC0-¥ = C0 kel Z = F x DOSE x kab Vd(kab – kel) kab = 0.693 t0.5 AUC0-¥ = Z - Z kel kab Css = rate of infusion Clp Css = F x DOSE Clp x t interval a. How much of salbutamol (in micrograms) will remain in the body 15 hours after intravenous administration to 1dp? 3 marks b. Calculate the elimination rate constant to 3 sf (hr-1) 2 marks c. Given that the initial plasma concentration of salbutamol was 1.6 µg/L, calculate the apparent volume of distribution (L) to 3 sf 1 mark d. Comment on the value obtained for volume of distribution. What does this indicate with respect to drug distribution in the body? 1 mark e. Calculate the plasma clearance (Lhr-1) for salbutamol to 3 sf Total 30 marks 1 mark Question 2 You are the responsible pharmacist working in the dispensary of a hospital pharmacy department when a cardiology consultant calls you asking for some advice. He wishes to prescribe some mexile ne for an adult male pa ent with ventricular tachycardia but is unsure whether this is available. You look up the drug and discover that it is an unlicensed medicine which the pharmacy stocks. Part A What is meant by an ‘unlicensed medicine’? How does this differ from a medicine prescribed ‘off-label’? Explain your answer. 3 marks Part B What are the prescriber’s responsibili es in rela on to the pa ent if he wishes to prescribe the mexile ne? Explain your answer. As part of your answer, you must include: a. what considerations the prescriber must make BEFORE deciding to prescribe this medication b. any information that the prescriber must provide the patient with BEFORE prescribing the medication. 7 marks Part C Tachycardia is a condition where the heart beats faster than normal. Answer the following questions related to heart rate: a. What autonomic innervation pathway increases heart rate when it is activated and what receptor is activated by this pathway in the heart cells? b. What autonomic innervation pathway decreases heart rate and what receptor is activated by this pathway in heart cells? c. How does heart rate influence blood pressure? d. Which structures of the heart co-ordinate the heartbeat? e. What clinical investigation would you carry out to know if a patient has tachycardia? 6 marks Part D Given the structure of mexiletine, shown below, a. Redraw the structure of mexiletine, and clearly label the hybridisation of all carbon, oxygen and nitrogen atoms in mexiletine 3 marks b. Draw all possible stereoisomers for the compound c. Assign all the stereocentres on all stereoisomers using on using Cahn-IngoldPrelog rules 3 marks d. Define the relationship between the compounds. Part E What is the result of combining rifampicin with mexiletine? 2 marks 1 marks 2 marks Part F Mexile ne can also be used to treat muscle s ffness resul ng from myotonic dystrophy. Congenital myotonic dystrophy (CMD) is an autosomal dominant genetic disorder in the DMPK (dystrophia myotonica protein kinase) gene on chromosome 19q 13.3. Using the inheritance pattern diagram shown below, explain: a. What is the meaning of an autosomal dominant disorder? b. What will be the outcome on offspring (children) if the disease is recessive? Total 30 marks 3 marks