TUM202 Therapeutic Use Of Medicines


David is an Aboriginal male, who has been admitted to the hospital due to H.pylori infection. He has developed acute abdominal pain, which requires urgent attention. To manage his pain, he takes ibuprofen and paracetamol. However, he was taking these drugs in his home regularly, without any medical supervision. However, after admission to the hospital, he has been given Mylanta, Clarithromycin, Paracetamol, Amlodipine, Transiderm, Atorvastatin and Metformin. Following the administration of these drugs, his condition gets improved. However, at 7 am he reported having dark urine, muscle pain, fatigue, and breathing problem. Therefore, this paper is going to analyse possible drug-drug interactions, which may be the reason for this complication, also relevant strategies to improve the condition.  


Polypharmacy can be defined as regular consuming more than five medications. However, there is no limit to five medications. The number of medications may be more than five. As a result of taking more than five medications, the chemical composition of a drug can interact with the composition of another drug. This may lead to severe conditions, if not managed properly. Therefore, not all drugs can go with other drugs. Also, there is a chance of side effects due to the adverse drug-drug interaction (Masnoon et al., 2017).

Generally, older people are at increased risk of having polypharmacy. With age, the number of health complications increases, as a result the number of drugs also increases. This can lead to the development of adverse drug-drug interactions, which may have severe health consequences. Due to the negative consequences of polypharmacy, the chance of memory loss, drug overdose, fall risk even death increases. It has been identified that the main reason for developing polypharmacy among older people is taking the self-medicated medication without proper understanding (Kim & Parish 2017).

Also, as the patient’s condition deteriorated due to polypharmacy, it can have negative consequences on the affect care delivery. The possible effect of polypharmacy on the healthcare system includes a high rate of morbidity and mortality, cost burden, prolonged admission, patient dissatisfaction and a negative impact on a hospital’s reputation (Valenza et al., 2017).

Drug-Drug Interaction

In this case, the patient is mainly complaining about dark urine, muscle pain, breathing problem, and extreme fatigue. These can be possibly due to the adverse drug-drug interaction.  After critically analysing the drugs prescribed to David, possible drug-drug interactions are 1. clarithromycin metformin drug interactions, 2. atorvastatin clarithromycin interaction, 3. amlodipine clarithromycin interaction, and 4. paracetamol and ibuprofen reaction.  Among these paracetamol and ibuprofen both are used as pain killers, clarithromycin is an antibiotic to kill H. pylori, metformin is used to manage the blood glucose level (BGL), atorvastatin is used to manage cholesterol, and amlodipine is used to improve blood circulation (Rodrigues 2019).

Patient Symptom

All of these above-mentioned conditions can affect the condition, David, negatively. Clarithromycin and metformin can interact with each other; using both of these drugs in combination sometimes leads to very low blood sugar or hypoglycaemia. Hence, as the level of sugar falls, the brain receives less glucose, which can lead to disorientation. Also, due to hypoglycaemia, the level of blood pressure decreases. As a result, the patient feels weaker and fatigues. Also, this interaction can increase the chance of rapid heart rate, nausea and palpitation (Vermeer et al., 2016). In this case, David has also developed a similar condition. He has a BGL of 6.5mmol/L and BP of 103/62, both of which are below the normal level. Also, he has developed weakness and slight disorientation (GCS 14). Therefore, these conditions might suggest clarithromycin-metformin interaction.

Atorvastatin clarithromycin interaction can increase the chance of a high level of atorvastatin in the blood. Due to this, the liver might not be able to manage this extra level of atorvastatin; as a result, the chance of liver damage increases. Moreover, in some rare cases, it might lead to rhabdomyolysis. In this condition, skeletal muscle breakdown happens (Hougaard Christensen et al. 2020). As a result, it can cause protein loss with urine. This will lead to darker urine formation. Moreover, loss of skeletal muscle can increase the chance of muscle fatigue and muscle pain. Also, due to liver damage, the level of bilirubin increases in the urine, which can make it darker. Similarly, in this case, David also reported having darker urine. Hence, it can indicate possible atorvastatin-clarithromycin interaction.

Clarithromycin can also increase the level of amlodipine in the blood. As a result, it can increase the chance of hypotension, cardiovascular problem, swelling, fluid retention, and arrhythmia. Due to the cardiovascular problem and hypotension, the patient feels extremely fatigued. Also, due to the irregular heart rate, the chance of breathing problem increases. Additionally, fluid retention causes storage of water in the body cavities. It can also increase the chance of fluid retention inside the lung causing breathing problem (Takeuchi et al., 2017). Also, dehydration can occur due to severe fluid retention. This can cause a low amount of fluid in the urine, decreasing urine volume and making it darker (Hooper et al., 2016). Here, David also reported having breathing problems and low urine volume with a darker colour, indicating the clarithromycin- amlodipine interaction.

Additionally, too much use of paracetamol and ibuprofen can affect normal liver function, as both of them are pain killers. Also, this can lead to muscle pain and fatigued, causing severe weakness (Maryam et al., 2020).

Strategy For Improvement

To identify the possible complication of polypharmacy, it is important to perform routine assessments and check the vital signs of the patient. Hence, in this case, the nurse needs to check the vital signs of David every 15 minutes to identify any possible chance of drug-drug interaction. To identify drug-drug interaction, according to Valenza et al. (2016) stress should be given on system-level factors, physician factors, and patient factors.  System-level factors include the use of a proper electronic heath recorder system, proper communication between the professionals, good ISBAR technique and quality care. Physician factors include the use of proper guidelines and pathophysiological and pharmacological knowledge, and patient factors included understanding of the patient’s condition and disease indication.

Additionally, Grizzle et al. (2019) mention the nurse can use web-based survey strategies, which can help to detect possible drug-drug interactions.  Grizzle et al. (2019) mention the nurse needs to have adequate knowledge about database search including Google Scholar, EMBASE and other relevant web site. They need to properly search for general information about the drugs, side effects, health consequences and management. Additionally, Sun et al. (2021) proper nursing education as well as a multi-disciplinary approach is necessary to identify drug-drug interaction.

According to these strategies, to identify David’s condition the nurse needs to effectively analyse all the subjective, objective data and current vital signs of David. Also, the nurse needs to critically analyse the patient’s condition and how it can be related to the prescribed drug. Additionally, the nurse needs to follow NMBA RN standard 6 (Cashin et al., 2017), to provide safe and quality care to David. Also, as per the NSQHS standard 4: medication safety (Jensen, 2020), the nurse needs to perform the documentation for each of the drugs. The nurse needs to provide the correct dose of medication to the patient to reduce the chance of adverse outcomes. For this, the nurse can use the “5Rs” technique for effective drug delivery. As per this concept, it is important to deliver the right amount of drug, at right time via the right route to the right patient. Moreover, evidence suggests implementation of advanced training programs to improve the competence of polypharmacy is important to prevent the chance of drug-drug interaction among patients.

To improve the condition of David, the focus should be given to a person-centred approach. This type of care can provide better medicine optimisation, which would be patient-centred. Also, it can help to improve the understanding of the nurse regarding the patient’s condition. Evidence suggests that the person-centred approach is more save to improve the clinical outcome of the patient (Valenza et al. 2016). To provide an effective person-centred approach the nurse needs to build effective rapport with David, acknowledge his concern, and provide necessary patient education. The nurse needs to tell David about the possible side-effects of each of these medications and how to take this medication to prevent drug-drug interaction. However, an MDT approach is necessary to improve David’s condition. The MDT team can include RN, pharmacists, and case physicians (Valenza et al. 2016). However, here the role of the pharmacist will be important to identify possible drug-drug interactions and determine the safe dosage of medication for David. The nurse will be responsible for administering the medication and checking the condition David. However, the situation needs to be reviewed by the case physician to make sure everything is going according to the plan.    


David has been administered clarithromycin to manage H. pylori. However, this drug can interact with other medications, which may be causing degradation of patient health. Clarithromycin adversely interacts with metformin, atorvastatin, and amlodipine. As a result, David has developed dark urine, breathing problem and muscle pain. Hence, to improve the condition, it is important that the nurse properly identify possible drug-drug interactions and take necessary steps to improve the condition. In this case, providing person-centred care is effective to improve the condition David.


Cashin, A., Heartfield, M., Bryce, J., Devey, L., Buckley, T., Cox, D., … & Fisher, M. (2017). Standards for practice for registered nurses in Australia. Collegian, 24(3), 255-266. https://doi.org/10.1016/j.colegn.2016.03.002

Grizzle, A. J., Horn, J., Collins, C., Schneider, J., Malone, D. C., Stottlemyer, B., & Boyce, R. D. (2019). Identifying common methods used by drug interaction experts for finding evidence about potential drug-drug interactions: a web-based survey. Journal of medical Internet research, 21(1), e11182. doi:10.2196/11182

Hooper, L., Bunn, D. K., Abdelhamid, A., Gillings, R., Jennings, A., Maas, K., … & Fairweather-Tait, S. J. (2016). Water-loss (intracellular) dehydration assessed using urinary tests: how well do they work? Diagnostic accuracy in older people. The American journal of clinical nutrition, 104(1), 121-131. https://doi.org/10.3945/ajcn.115.119925

Hougaard Christensen, M. M., Bruun Haastrup, M., Øhlenschlæger, T., Esbech, P., Arnspang Pedersen, S., Bach Dunvald, A. C., … & Thestrup Pedersen, A. J. (2020). Interaction potential between clarithromycin and individual statins—A systematic review. Basic & Clinical Pharmacology & Toxicology, 126(4), 307-317.

Jensen, F. (2020). Partnering with consumers through NSQHS standards. Journal of Health Information and Libraries Australasia, 1(1), 18-19. https://www.johila.org/index.php/Johila/article/view/9

Kim, J., & Parish, A. L. (2017). Polypharmacy and medication management in older adults. Nursing Clinics, 52(3), 457-468. https://doi.org/10.1016/j.cnur.2017.04.007

Maryam, B., Buscio, V., Odabasi, S. U., & Buyukgungor, H. (2020). A study on behaviour, interaction and rejection of Paracetamol, Diclofenac and Ibuprofen (PhACs) from wastewater by nanofiltration membranes. Environmental Technology & Innovation, 18, 100641. https://doi.org/10.1016/j.eti.2020.100641

Masnoon, N., Shakib, S., Kalisch-Ellett, L., & Caughey, G. E. (2017). What is polypharmacy? A systematic review of definitions. BMC geriatrics, 17(1), 1-10. https://doi.org/10.1186/s12877-017-0621-2

Rodrigues, A. D. (Ed.). (2019). Drug-drug interactions. CRC Press. https://books.google.co.in/books?


Sun, W., Grabkowski, M., Zou, P., & Ashtarieh, B. (2021). The Development of a Deprescribing Competency Framework in Geriatric Nursing Education. Western journal of nursing research, 43(11), 1043-1050. https://doi.org/10.1177/01939459211023805

Takeuchi, S., Kotani, Y., & Tsujimoto, T. (2017). Hypotension induced by the concomitant use of a calcium-channel blocker and clarithromycin. Case Reports, 2017, bcr2016218388. https://dx.doi.org/10.1136/bcr-2016-218388

Valenza, P. L., McGinley, T. C., Feldman, J., Patel, P., Cornejo, K., Liang, N., … & McNaughton, N. (2017). Dangers of polypharmacy. In Vignettes in Patient Safety-Volume 1. IntechOpen. DOI: 10.5772/intechopen.69169

Vermeer, L. M., Isringhausen, C. D., Ogilvie, B. W., & Buckley, D. B. (2016). Evaluation of ketoconazole and its alternative clinical CYP3A4/5 inhibitors as inhibitors of drug transporters: the in vitro effects of ketoconazole, ritonavir, clarithromycin, and itraconazole on 13 clinically-relevant drug transporters. Drug metabolism and disposition, 44(3), 453-459.