In the provided case scenario, patient JJ has a history of strokes and has subsequently been diagnosed with type 2 diabetes, hypertension, and hyperlipidemia. The patient is also currently on prescribed medications, including glipizide 10mg PO daily, metformin 500mg PO daily, HCTZ 25mg daily, Atenolol 25 mg PO daily, Hydralazine 25 mg QID, Simvastatin 80mg daily and Verapamil 10 mg CD daily. This paper examines how drugs currently prescribed influence the patient’s pharmacokinetic and pharmacodynamic processes, how changes in the processes might impact the drug therapy, and how to improve or modify the current drug therapy plan.
How Prescribed Medications Affect Pharmacodynamics And Pharmacokinetics
Pharmacokinetics are processes in a body that subject drugs once introduced to the body; it includes absorption, distribution, metabolism, and excretion (Tornio et al., 2019). On the other hand, pharmacodynamics is the effect drugs have on the body. In the provided scenario, the medical history of the patient and the currently prescribed medications, as well as patient characteristics such as age and sex, affect the patient’s PK and PD. Treating patients with comorbidities is always challenging. For instance, patients with cardiovascular and other illnesses often require different drugs, which tend to have different reactions and adverse effects (Gabay, 2019). Patient JJ has a prior stroke history and suffers from several ailments, including type 2 diabetes mellitus, hypertension, and hyperlipidemia. All these conditions are most likely to play a significant role in the patient’s PK and PD. For example, patients with diabetes usually have challenges in excreting toxins from the kidney, which puts them at a heightened risk of developing diabetic nephropathy, complicating their treatment even further.
Process Changes Impact On The Patient’s Recommended Drug Therapy
The process changes brought about by medication currently used by the patient alter drug clearances. Therefore, any dosage regime, such as atenolol, must be modified to minimize the risk of adverse side effects. The Glipizide action mechanism acts upon the pancreatic islets’ beta cells to stimulate insulin release from the pancreas. Glipizide fall in the category of oral sulfonylurea hypoglycemic agents. It treats high levels of blood sugar due to type II diabetes. Absorption of Glipizide is rapid and complete with a half-life of 2 to 4 hours and given PO or IV. The adverse effect of Glipizide includes nausea, loss of appetite, vomiting, constipation, weight pain, and headache, among others.
Metformin mechanism of action entails energy metabolism alteration of the cells. It exerts glucose lowering, its prevailing impact by inhibiting hepatic gluconeogenesis and glucagon antagonism. It falls under the biguanides drug class and helps control the sugar level in the blood. Absorption is slow, and the oral bioavailability under fasting conditions is 50-60. Also, it has peak plasma concentration within 1-3 hours (Lea-Henry et al., 2018). The adverse effect of metformin includes a metallic taste in the mouth, stomach ache, loss of appetite, diarrhea, and sick feeling.
Hydrochlorothiazide works by inhibiting the transport of sodium chloride in the distal convoluted tubule. The more sodium ions are excreted in the kidney, the more fluid is excreted. HCTZ falls under the class of diuretics and works by causing the kidney to release excess water and salt from the body. The drug is not metabolized however it is eliminated through the renal system. The adverse effects of HCTZ include pilling skins, blue lips, chest pains, clay-colored stools, and bloating.
Atenolol falls under the drug class of beta blockers, which acts by blocking the impact of the hormone epinephrine. Beta-blockers make the heart beat slowly and with a lower force, reducing blood pressure. Also, Beta-blockers cause vasodilation. After oral ingestion, it is incompletely absorbed into the body through the intestines. Therefore, half of the beta block remains bioavailable. Metabolism happens in the liver, and excretion is predominantly in the renal system (Mukhtar & Jackson, 2015). The use of the drug might cause heart failure among patients, shortness of breath, face swelling, and feet or lower legs.
Hydralazine is a drug found in the drug class of vasodilators. The drugs work by relaxing the blood vessels to ease the flow of blood through the body. By doing so, the body is capable of regulating blood pressure. Gastrointestinal absorption is good, and the metabolism process is complex and extensive depending on the acetylation status (Mukhtar & Jackson, 2015). The adverse effect of hydralazine includes flushing, vomiting, diarrhea, constipation, loss of appetite, and eye tearing.
Simvastatin works using the Acetyl-CoA, which acts as a substrate, forms mevalonic acid, and, following reaction, forms cholesterol. It acts on the rate-limiting step and serves as an HMG CoA reductase inhibitor, which helps the robust reduction of cholesterol in the body. It is a statin that is an HMG-CoaA reductase inhibitor (Mukhtar & Jackson, 2015). Simvastatin is well absorbed in the gastrointestinal tract and liver metabolized. The adverse effect of the condition entails stomach pain, especially in the lower abdomen. The drug also leads to headaches, nausea, confusion, and skin itching.
The Verapamil mode of action entails inhibition of calcium ion influx through slow channels of contractile and conductible myocardial cells. Also, the inhibition happens by the influx of slow channels to smooth muscle cells. It controls angina and arrhythmias and lowers the level of blood pressure. The drug has good oral absorption as more than 91% of the drug is absorbed orally and transported bound to plasma proteins (Mukhtar & Jackson, 2015). The adverse effect of verapamil includes blue lips and fingernails, coughing, dizziness, coughing, and shortness of breath.
Therapy Plan Improvement
Considering the assumed patient age factor, we need to modify the drugs given for the effective treatment of the patient and to prevent other health risk factors from the drugs. First, hydralazine needs to be avoided in elderly patients because of the significant side effect, including exacerbation of ischemic heart disease and tachycardia. Consequently, the elimination of the hydralazine will secure the elderly patient from contracting a stroke. Second, the dose of Glipizide requires a reduction to reduce hypoglycemia risk (Mukhtar & Jackson, 2015). Therefore, the quantity of the drug should be reduced to 2.5mg OD.
Metformin should be used alongside Glipizide to lower blood sugar. Since it has a low risk of an elderly patient going into hypoglycemia, there is no need for dose adjustment. Atenolol use should reduce because heavy intake is a risk factor for kidney, heart, and liver conditions. The Verapamil dose should not be adjusted or eliminated because the old patient has no kidney or liver complications (Kim et al., 2015). Therefore, it is safe for the old-age patient to use.
References
Gabay, M. (2019). Drug Interactions: Scientific and Clinical Principles. Am Fam Physician, 99, 558-64. https://www.accp.com/docs/bookstore/psap/p2021b3_sample.pdf
Kim, H., Kisseleva, T., & Brenner, D. A. (2015). Aging and liver disease. Current Opinion in Gastroenterology, 31(3), 184. http://doi:10.1097/MOG.0000000000000176
Lea-Henry, T. N., Carland, J. E., Stocker, S. L., Sevastos, J., & Roberts, D. M. (2018). Clinical pharmacokinetics in kidney disease: Fundamental principles. Clinical journal of the American society of nephrology, 13(7), 1085-1095.
https://doi.org/10.2215/CJN.00340118
Mukhtar, O., & Jackson, S. H. (2015). Drug therapies in older adults (part 1). Clinical Medicine, 15(1), 47. https://doi:10.7861/clinmedicine.15-1-47
Tornio, A., Filppula, A. M., Niemi, M., & Backman, J. T. (2019). Clinical studies on drug–drug interactions involving metabolism and transport: methodology, pitfalls, and interpretation. Clinical Pharmacology & Therapeutics, 105(6), 1345-1361. https://doi.org/10.1002/cpt.1435
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