Pharmacological Processes in Post-Operative Pain Management

Nursing
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Case study 2
Introduction
This essay assignment will use the Pasha Smirnov case study. Post-operative pain
management will be discussed focusing on the pharmacological processes of the drugs used,
medicines management issues nursing care and safe practice and lastly the nurse’s role in the
management. Pasha Smirnov is an 83-year-old patient and has a past medical history of severe
osteoarthritis, where he has experienced a persistent hip and joint pain for the past 5 years. His
medical condition made him undergo a right total right hip replacement, though the surgery went
on uneventful with no complications the patient has to be managed for the post-operative acute
pain. Pain reduction is done medically by administering analgesics. In the second topic, the essay
will explain the nursing role in drug administration referring to the 6Rs, it will also include the
nursing assessment in drug administration before the operation, during the operation, and after
the operation as well. Then it will evaluate the effectiveness of the medication and their different
side effects. The third part of the essay will take note of the nursing care focusing majorly on the
types of pain, pain assessment, pain tools, type of pain the patient is experiencing and how it can
be managed. The fourth part will include the safe practice of the and the nurse’s role focusing on
critical thinking and decision-making skills and professional issues referring to NMC2015.
Lastly, the essay will have the conclusion part which will summarize all the discussed topics.
Pharmacological processes.

Pharmacological processes including pharmacokinetics, pharmacodynamics and side effects
of the medication administered are discussed. The pharmacokinetics means the action of the
body on the drug (Smith & Williams, H., 2014). Pharmacokinetics includes the ADME
(absorption, distribution, metabolism, and excretion), bioavailability, plasma half-life, peak
plasma concentration, and synergism. The pharmacodynamics which is the action of the drug on
the body describes the mechanism of action of the drug, the drug’s side effects, selectivity
affinity and efficacy. Then talking of adverse drug reactions is simply the side effects that might
be brought by a certain type of drug when administered. Different drugs have different specific
side effects.
Morphine is an opioid analgesic used for the management of chronic to moderate-to-severe
pain (Shaheed et.al 2016, p 176). Morphine is almost completely absorbed mainly done in an
alkaline environment. It is administered intravenously and its steady-state concentration is
achieved after 24-48 hours of initial administration. It has a low volume of distribution of
approximately 5.31L/kg. has got a low protein binding approximately 30% plasma protein
bound. Morphine is fluorinated and sulfated by glucuronosyltransferase-2B7 in the liver to give
out glucuronide metabolites. Morphine has a half-life of 2-3 hours. (Eissing, Lippert &
Willmann 2012, pp 43-53). The elimination of morphine and its metabolites is through the urine.
Morphine as an agonist bind in the mu and kappa receptors, blocking the transmission of the
nociceptive signals. it activates the signaling of the pain-modulating neurons in the spinal cord
and this inhibits the transmission of the stimulus from the primary afferent nociceptors to the
dorsal horn sensory projection cells.
Paracetamol is an active metabolite of phenacetin (Shastri 2015, pp 444-448). Administered
to Pasha Smirnov orally at a dosage of 1 gram four times a day. It has 88% oral bioavailability

and reaches peak plasma concentration 90 minutes after ingestion. It is indicated as a mild to
moderate analgesic. Paracetamol is a weak prostaglandin inhibitor that is centrally acting. Its
mechanism of action is that it is a potent inhibitor of cyclooxygenase 1 and 2 (Saliba et al 2015,
p 246). COX 1 and COX2 are the enzymes that are capable of producing prostaglandins that
promote pain. Its absorption rate is increased by metoclopramide and as well reduced by high
carbohydrate meal. It is 20-30% protein bound. Rapidly metabolized in the liver following the
first order kinetics giving out two inactive metabolites; acetaminophen and glucuronide
(Mazaleuskay et.al 2015, p 416). Acetaminophen has a plasma half-life of 75-180 minutes.
Acetaminophen’s adverse effects when administered are; liver enzymes increasing slightly,
rashes, methemoglobinemia, and symptoms of liver damage that can manifest in 2-4 days.
Acetaminophen appears to be widely distributed to most of the body tissues. acetaminophen
metabolites are primarily excreted in the urine. Acetaminophen interacts with warfarin, isoniazid,
difunisal, carbamazepine, phenobarbital, and phenytoin (Donaldson 2014, pp 83-107).
Enoxaparin sodium is an anticoagulant drug. Indicated for prophylaxis of deep vein
thrombosis and pulmonary embolism to those who have undergone surgery. It is also used to
prevent clots by making the blood smooth hence flowing easily to all the body tissues. It is
administered 40 mg once per day subcutaneously. The mechanism of action of Enoxaparin is that
it binds to antithrombin III and accelerates the activity of antithrombin III (Nutescu et al 2016,
pp 296-311). It, therefore, potentiates inhibition of coagulation factors Xa and IIa, resulting in
decreased thrombin and ultimately the prevention of the fibrin formation. Absolute 100%
bioavailability.it is 80% protein bound. For the metabolism, it undergoes desulfation and
polymerization to lower molecular weight species with much reduced biological potency. It has a
half-life of 4.5 hours. Eliminated through the renal route. Enoxaparin’s common side effects