Understanding Pharmacokinetics and Pharmacodynamics and Clinical Decision-Making Process | Essays

Running head: CASE STUDY
CASE STUDY
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CASE STUDY
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Topic1: Understanding Pharmacokinetics and Pharmacodynamics
Pharmacokinetics:
Pharmacokinetics is a branch of the pharmacology that determines the fate of the
substance administrated to the human body. The substance of the interest includes
pharmaceutical drugs, pesticides and other food additives (Kaukab et al., 2019). In other words,
it is the way body influence the drug when it is administrated.
Absorption:
As discussed by Caillé et al. (2018), metoclopramide is a dopamine antagonist drug that
used for treating nausea. It is rapidly absorbed by the gastrointestinal tract after administration
with absorption of approximately 84%. The bioavailability of the drug is 40. 7%.The onset
difference between administrating metoclopramide oral vs intravenous is that in case of oral
administration of the medication, the medication has to go through the first-pass metabolism of
the liver where the concentration of a drug is reduced to reach in the circulation and rest
eliminated through excretion (Kenward et al., 2017). Hence, while in intravenous administration
has 100% bioavailability, oral administration has a 40% of the bioavailability. The best way of
administrating antiemetic is the intravenous route since the feeling of nausea is coming from the
hypothalamus and intravenous will provide the immediate effect.
Distribution:
The protein binding refers to the degree to which medications bind to the protein in the
blood. The volume of distributions to the metoclopramide is approximately 3.5 l/kg. it implies a
high level of tissue distribution and it can cross the placenta barriers (Madisch et al., 2017). The
metoclopramide can 30% bound to plasma protein, specifically to the alpha-1 acid glycoprotein.
Metabolism:

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The importance of the metabolism of this drug into glucuronide and sulfate conjugates
is that glucuronide increase the activity of the drug by attaching with the drug and facilitating
circulation. On the other hand, the importance of sulfur conjugate is that it can induce phase two
reaction where the drug metabolites such as glucuronide attached to sulfur conjugate to eliminate
the toxic substances from the body and eventually reduce the feeling of nausea (Kaukab et al.,
2019). The metabolism of the drug occurs in the liver as the majority of the drug metabolised in
the liver. The underlying reason is that the liver has the enzymes that convert the prodrugs into
active metabolites (Meegada et al., 2016). The metabolism occurs through a specific group of
cytochrome P-450 enzymes.
Excretion:
The main organ responsible for the drug excretion is the kidney where the administrated dose
is eliminated through urine within 72 hours. 18% to 22% of 10-20 mg dose was recovered as free
drugs after 3 days of consumption of drugs (Zoufal et al., 2019).
The importance of monitoring the kidney function is that it will provide the idea that whether the
health status of the patient is improved or not. The proper function of kidney indicates an
improvement of health status after the drug (Griffin, Faubel & Edelstein, 2019). Since the
patient has Mild renal impairment, it is crucial to assess for improvement. As discussed by
Fraser and Blakeman (2016), patients with mild to moderate renal impairments may exhibit up
to 50 % of clearance compared to the patients with healthy renal status. In this context,
monitoring the kidney function is crucial to track the elimination and clearance percentage.
The half-life defined as the duration of action of specific drugs. The elimination half-life
of this drug in individuals with healthy renal function is approximately 5 to 6 hours. In this