Pharmacology Case Study 1 Anticoagulation

David Drummond, a 66 year male is recovering from bowel surgery in hospital. On day three he develops tenderness, pain and warmth in his right calf.

1. His doctor determines that he has developed thrombophlebitis and orders:

Given your knowledge of this medication, why is a bolus dose required prior to commencing the heparin infusion?

2. This therapy is continued for four days, after which Mr Drummond is started on the following medication schedule:

Given your knowledge of these drugs and their use in anticoagulant management, why is Mr Drummond receiving both a subcutaneous and an oral anticoagulant for several days?  

3. Prothrombin times are done daily. Mr Drummond's doctor adjusts his dosage of warfarin sodium accordingly. He responds well to therapy and is discharged from hospital with a prescription for warfarin sodium 5 mg PO daily.

Given your knowledge of this medication, explain the laboratory testing that is required to monitor the effectiveness of warfarin? How does this impact on the dosing of this drug?

Pharmacology Case Study 2 Duodenal Ulcer

George Grayson is a 42 year old man with a highly stressful job at a large corporation. He has had recurrent episodes of abdominal pain, heartburn and occasional vomiting for the last two years. He describes the pain as a burning sensation. It is usually most severe just prior to meals and subsides on ingestion of a meal. George smokes two packs of cigarettes and drinks eight cups of coffee each day. 

1. His GP orders a variety of tests, including the urea breath test, which tests positive for the presence of Helicobacter pylori. Mr Grayson is diagnosed as having a duodenal ulcer cause by H.Pylori. His GP prescribes:

Given your knowledge of this medication, explain the role of each of the medications in this treatment plan? Why is triple therapy used for treating peptic ulcers caused by H.pylori

2. Given your knowledge of these medications, why does Mr Grayson need to take his omeprazole 30 minutes before a meal?  How would you explain the importance of this to George?

Given your knowledge of this medication (Omeprazole), could George take antacids as well, and if so, when should they be taken?

Pharmacology Case Study 3 Depression

Chris is a 23 year old man, who lives with his girlfriend in the city. He has been feeling constantly tired, finding it difficult to get to sleep, and when he does get to sleep he wakes up frequently during the night. He doesn't really care about eating and has no energy or enthusiasm for anything. His girlfriend, Jenny is very worried because Chris is becoming more and more withdrawn from his friends, family and her. Jenny believes the change in Chris occurred after his father died from a heart attack five months ago. Jenny has managed to encourage Chris it got to the doctor. 

1. Chris and his GP have a lengthy discussion, and he is prescribed fluoxetine 20mg and is referred to a counsellor. ​​​​​​​

Given your knowledge of this medication, why has the GP chosen to prescribe fluoxetine? Why has the GP chosen fluoxetine over other antidepressants such as moclobemide or amitriptyline

2. Given your knowledge of medications used to manage depression, discuss how having an understanding of neurotransmitter function can be used to develop medications for treating depression. 

3. A concern that arises with the use of antidepressants is the risk of overdose, since suicide is a known risk for a person who is depressed. Which of the antidepressant medication classes cause the greatest problems with overdose and what are the symptoms to watch out for?

Pharmacology Case Study 4 Analgesia

Vicki, a 57-year-old woman, has suffered from osteoarthritis for the last 2 years. Since Vicki has a history of aspirin sensitivity (which manifests as bronchospasm), NSAIDs are contraindicated. She initially used paracetamol for analgesia, but due to worsening pain Vicki’s general practitioner prescribed panadeine forte, two tablets 8-hourly.

Vicki obtains no additional benefit from the panadeine forte, and in frustration she takes a ‘couple of handfuls’ (later estimated as about 30 tablets) of panadeine forte tablets. After 2 hours Vicki felt nauseous and told her husband what she had done. Vicki’s husband took her to the emergency department of their local hospital.

1. Vicki was immediately administered activated charcoal, 50 g. The plasma paracetamol concentration 4 hours after the overdose was measured as 180 mg/L. ​​​​​​​

What is the likelihood of hepatotoxicity, as assessed from Vicki's plasma paracetamol concentration? What is the mechanism of paracetamol hepatoxicity?

(Note: Your answer should take into consider Vicki's medical history and all medication received. Remember to incorporate latest evidence based practice in your answer)

2. Vicki was treated with intravenous N-acetylcysteine, according to the standard protocol.

What is the mechanism of action of N-acetylcysteine? Why is glutathione not used as an antidote?

(Note: Your answer should take into consider Vicki's medical history and all medication received. Remember to incorporate latest evidence based practice in your answer)

3. Vicki’s husband later admitted to the treating doctor that she had been drinking alcohol excessively for some months.

Can excessive ethanol intake affect the severity of paracetamol hepatotoxicity?

Pharmacology Case Study 5 Duiretics

Betty Johnson, a 72-year-old, who is currently taking Perindopril 5mg and hydrochlorothiazide 25mg for the treatment of hypertension, twisted her ankle while out walking in the morning. The nurse at the residential care facility where she lives treated her ankle with an ice pack and later strapped the ankle and advised Betty to elevate her leg as much as possible over the next 48 hours. The nurse also advised Betty if she felt she needed some pain relief she was to consult with her (the nurse) and she would give her some paracetamol.

1. Discuss the effect of the combination of an ACE inhibitor and a diuretic on renal haemodynamics.

2. Later that day Betty’s daughter arrived and, when Betty complained of ankle pain, the daughter said she would leave some pain killers for her instead of bothering the nurse. Betty took 6 tablets over the next 12 hours. Later that evening during a routine check Betty tells the nurse she has taken some of her daughter’s pain killers, which turn out to be the non-steroidal anti-inflammatory drug ibuprofen (200-mg tablets). The nurse advises Betty that she is to cease the drugs immediately

Discuss the likely implications of Betty taking ibuprofen.

3. What patient education should the nurse provide about diuretic therapy?

Pharmacology Case Study 6 Polypharmacy and the Elderly

Yvonne Chen is an 86 year old resident of an aged care facility. She has lived at the facility for four years, she speaks Mandarin. Her failing vision is inadequately corrected with glasses and she has difficulty hearing. In addition to these sensory deficits, she has a number of physical and mental health problems resulting from generalised arteriosclerosis. She spends much of the day in her room and shows little interest in the activities taking place around her. She takes her meals in the communal dining room.​​​​​​​

1. What challenges does Yvonne's sensory deficits provide in ensuring adherence with her medication regime. 

2. ​​​​In addition to the array of medications that Yvonne routinely receives, she is taking several others for a respiratory infection that has been troubling her for a week. Her 0800 medications include:

Given your knowledge of these drugs, in what order would you administer them? Why?  

3. Polypharmacy is common in the elderly, it increases the risk of medication-medication errors and the development of adverse effects. 

Given you knowledge of her medication, identify and discuss what can be done to reduce medication interactions or detrimental effects for Yvonne.