Safe Administration of Medications: Understanding Pharmacokinetics and Pharmacodynamics

Administration of Medications 1
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Report Title: Safe Administration of Medications
Word Count: 2,059
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Administration of Medications 2
Question one
Phase I
Phase I studies examine the safety of a drug or device. It involves healthy volunteers
ranging from 20 to 100, who are rewarded for being involved in the research. The objective is
to ascertain the effects of the drug or device on humans and can last for several months.
Phase II
This phase tests the drug or device efficacy. It includes multiple hundred patients and
lasts for months to two years. The study is mostly randomized control trials comprising of
experimental and control groups
Phase III
Involves randomized and blind testing of multiple hundreds to thousand patients and
can take many years. Pharmaceutical companies can ask for FDA approval after the
completion of phase III. It provides the company with an in-depth understanding of the
efficacy of the drug.
Phase IV
Phase IV studies are undertaken after the approval for consumer purchase.
Pharmaceutical companies at this phase are aimed at comparing the drug with the ones
existing in the market. It involves thousands of participants (Pocock, 2013).
Question Two
a) The therapeutic goods administration (TGA) is under the Department of Health and is
charged with the responsibility of safeguarding and improving the health of the Australians.
TGA achieves this by regulating therapeutic goods in Australia, in addition to the manner in
which they are produced, imported, exported and promoted so that they are fit for human use.
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Administration of Medications 3
The regulation covers medicines sold by the counter and prescribed by the doctor or clinician,
blood products and surgical implants among others (TGA, n.d.).
b) The TGA regulates medications for use through pre-market assessment and licensing.
The pre-market assessment involves the evaluation of the risks of products against benefits.
TGA utilizes clinical and scientific professionals to make sure that the advantages outweigh
any risk. TGA also regulates products by providing licenses, and thus medicines have to be
indicated as ‘registered’ or ‘listed.’ TGA is thus able to take action against any drug found to
be dangerous (TGA, n.d.)
Question Three
Pharmacokinetics is the study of the time taken for a drug to be absorbed, distributed,
metabolized, and excreted. Pharmacokinetics is significant in improving efficacy and
minimizing the toxicity of a patient’s drug therapy. Pharmacokinetics has enabled physicians
to comprehend the association between drug concentrations and their pharmacologic
feedbacks. The impact of a drug is associated with its site of action. Thus it’s significant to
observe this concentration.
Pharmacodynamics is the association between drug concentration at the active site
and the resultant impact, in addition to the time taken and the concentration of therapeutic
and severe effects. The effect of a drug existing at the site of action is ascertained by the
binding between a receptor and the drug. There exists an association between the drug
concentration at the receptor site and the pharmacologic impact (Wang, Wang, & Balthasar,
2008).
Question Four
Some orally administered drugs such as pentazocine and morphine are immediately
absorbed from the intestines and transported first through the portal system to the liver, in
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Administration of Medications 4
which they are expansively metabolized. This process is referred to as the hepatic first pass
effect. Initial metabolic processes can take place during the phase of absorption in the gut
wall or liver before reaching the bloodstream. This leads to a reduction in the drug
concentration before it arrives in the circulation. This implies that some portion of the drug is
lost. Most of the oral drugs first pass through the liver and are then transported to the
systemic circulation from the gastrointestinal tract. Therefore, the liver can extract substances
from the GI tract, thus preventing its dissemination to other parts of the body. First pass
metabolism (the bioavailable fraction) determines the amount of oral dose that will end up in
the circulation. Drugs that are 100% bioavailable such as intravenous drugs do not undergo
the first pass effect. If drugs with the bioavailability of less than 20% are to be administered
orally, then they will have to be delivered five times the dose that is administered
intravenously in order to have the same impact (Wu, Kulkarni, Basu, Zhang, & Hu, 2011).
Question Five
a) Glyceryl Trinitrate (GTN) 600 microgram tablets must be administered sublingually and
are designed so because the area of the mouth contains an extensive supply of blood vessels
that permit the drug to be absorbed fast. Also, GTN undergoes high first-pass metabolism in
the liver, thus if administered orally, the liver will extensively breakdown/detoxify the active
drug molecule and therefore making it ineffective. Sublingual administration bypasses the
portal circulation of the liver and enables GTN to have direct access to the site of action
(Shakya, Madhav, Shakya, & Singh, 2011).
b) The GTN tablet should be kept in its original container. Transferring the tablets from
their original container may cause the active molecule to evaporate from the tablets. The lid
should tightly be closed after taking the tablet from it, and it should not be opened for over
eight weeks. The tablets must only be taken by being placed under the tongue (sublingually)
and allow them to dissolve slowly (Shakya, Madhav, Shakya, & Singh, 2011).
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