Nursing Questions

Nursing Questions

Question One: Possible Causes of Difficulty in Maintaining Balance

Diazepam is a benzodiazepine used in sleep and anxiety disorders. Benzodiazepines affect neuromuscular processing related to postural balance. Consequently, long-term use of these medicines among older people has been implicated in a sudden loss of balance control (Mandelli et al., 2017). The 70-year-old patient is experiencing difficulty maintaining her balance because of long-term exposure to diazepam. Also, her long history of diazepam use coupled with her age may exacerbate this side effect. Get in touch with us at eminencepapers.com. We offer assignment help with high professionalism.

Question Two: First-pass Effect and Circumvention of the First-pass Metabolism

Diazepam is extensively metabolized in the liver to form active metabolites with longer plasma half-lives. Demethylation of diazepam yields nordiazepam and oxazepam that maintains 25-30% activity of diazepam. The bioavailability of oral diazepam is significantly low (1-3%) due to this extensive first-pass effect (Mandelli et al., 2017). The first-pass effect on diazepam can be circumvented by using alternative routes for administering the drug. Injectable diazepam, as well as diazepam suppositories, are available. Administration of this drug with food may also increase its absorption and ensure high bioavailability.

Question Three: Causes of the Signs of Confusion

First-generation antihistamines such as diphenhydramine cause confusion among elderly patients. Phenylephrine also results in disorder among some older adults. Combining these two agents may result in profound confusion and disorientation. Consequently, these medicines should only be used upon consultation with a pharmacist.

Question Four: Warfarin Metabolism and Placental Barrier Crossing

Warfarin is an anticoagulant drug metabolized primarily in the liver by the hepatic microsomal enzymes. This drug exists as a racemic mixture. Additionally, the R enantiomer of warfarin is metabolized extensively by CYP1A2 to form 6-hydroxy warfarin or 8-hydroxy warfarin and by CYP3A4 to develop 10-hydroxy warfarin. Also, CYP2C9 metabolizes the S enantiomer of warfarin to form 7-hydroxy warfarin (Kaminsky & Zhang, 2016). Warfarin readily crosses the placental barrier and can cause fetal warfarin syndrome. Conversely, warfarin’s ability to cross the placental borders is attributable to its low molecular weight. It is for this reason that warfarin is contraindicated in pregnancy.

Question Five: Hepatic Metabolism of Drugs in Children Aged 1 Year and Above

Warfarin metabolism among children occurs in the liver. The hepatic warfarin metabolism among children is reduced because their microsomal enzymes are not fully developed. Microsomal enzyme activity gradually develops within the first few months after birth. The CYP2C9 and CYP1A2 systems often grow faster than the CYP3A4 system. As a result, metabolism by the CYP2C9 and CYP1A2 systems predominates among children below three years of age (Kaminsky & Zhang, 2016). Hepatic metabolism differs between children and adults. The microsomal enzymes are fully developed in adulthood, while these metabolizing systems are not fully developed in children (Wong et al., 2016). Children, therefore, metabolize warfarin slowly and have an increased propensity towards toxicity when given higher adult doses required for anticoagulation.

Question Six: Protein Binding in the Neonate

Warfarin is highly protein-bound, with a protein binding of over 90%. Albumin and p-glycoprotein are the predominant proteins to which warfarin binds. In neonates, the concentrations of these proteins are low. Accordingly, albumin is up to 70% of the adult concentration, while p-glycoproteins are up to 50 percent lower than the adult concentrations (Takahashi, 2017). Therefore, the protein binding of warfarin among neonates is significantly reduced, leading to a higher concentration of the unbound drug.

 References

Kaminsky, L., & Zhang, Z. (2016). Human P450 metabolism of warfarin. Pharmacology & Therapeutics, 73(1), 67-74. https://doi.org/10.1016/s0163-7258(96)00140-4

Mandelli, M., Tognoni, G., & Garattini, S. (2017). Clinical Pharmacokinetics of Diazepam. Clinical Pharmacokinetics, 3(1), 72-91. https://doi.org/10.2165/00003088-197803010-00005

Takahashi, H. (2017). Developmental changes in pharmacokinetics and pharmacodynamics of warfarin enantiomers in Japanese children. Clinical Pharmacology & Therapeutics, 68(5), 541-555. https://doi.org/10.1067/mcp.2000.110977

Wong, V., Cheng, C., & Chan, K. (2016). Fetal and neonatal outcome of exposure to anticoagulants during pregnancy. American Journal Of Medical Genetics, 45(1), 17-21. https://doi.org/10.1002/ajmg.1320450107

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Post your answers to the six questions corresponding to this week’s primary care medication management content. Provide your responses and rationales. Support your explanations with high-level evidence.

A 70-year-old woman is in your office complaining of recently having trouble maintaining her balance after taking diazepam (valium). She occasionally takes diazepam when she feels anxious and has trouble sleeping. She has a 15-year history of taking diazepam.

Q1. Explain the cause of this patient’s difficulty in maintaining her balance.

Q2. Diazepam experiences a significant first-pass effect. What is the first-pass effect, and how can first-pass metabolism be circumvented?

A 75-year-old woman develops cold symptoms and buys an over-the-counter cold medication at the grocery store. The drug contains diphenhydramine, acetaminophen, and phenylephrine. She takes the recommended adult dose, but soon after taking the medication, she becomes baffled and disoriented.

Q3. What is likely causing the signs of confusion?

A 26-year-old woman who has never been pregnant is seeking preconception care as she is planning to pursue pregnancy in a couple of months. Currently, she has no symptoms to report, and on review of body systems, there were no concerns. Her past medical history is significant for a history of rheumatic fever as a child. She subsequently underwent valve replacement with a mechanical heart valve. She is followed by a cardiologist who has already evaluated her cardiac function, and she has received clearance from her cardiologist to pursue pregnancy. Records from her cardiologist include a recent cardiac echocardiography report that reveals an average ejection fraction, indicating normal cardiac function.

She has no alterations in her daily activities related to her heart. She has no other significant medical or surgical history. She is a non-smoker, drinks occasionally but has stopped as she is attempting to conceive, and does not use any non-prescription drugs.

Current Medications: Her current medications include only prenatal vitamins, which she has begun in anticipation of pregnancy, and warfarin. She has no known drug allergies.

Vital Signs: On examination, her pulse is 80 beats per minute, her blood pressure is 115/70 mm Hg, her respiratory rate is 18 breaths per minute, and she is afebrile.

Measurements: Weight = 152 pounds, Height = 5′5 ″, BMI= 25.29

Q4. How is warfarin metabolized? Does warfarin cross the placental barrier?

Q5. Explain the hepatic drug metabolism of children one year and older. How do they compare with the hepatic drug metabolism of infants and adults?

Q6. Explain protein binding in the neonate.