Pharmacological Processes in Post-Operative Pain Management

This essay assignment discusses the pharmacological processes involved in post-operative pain management, focusing on the drugs used, their side effects, and the nurse's role in medication administration. It also explores nursing care and safe practice in managing pain. The case study revolves around Pasha Smirnov, an 83-year-old patient who underwent a total hip replacement.

Nursing
Student’s name:
Institutional:

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

include nausea, vomiting, diarrhea, fever, swelling in the hands and face and lastly injection site
reactions (Comerford, 2014). These side effects are evidenced by Pasha leading into taking only
fluids and difficult in performing physiotherapy activities. Drug interactions include interaction
with aspirin and ibuprofen.
Ondansetron is a competitive serotonin Type 3 receptor antagonist (Kovac 2016, pp 1719-
1735). Indicated to Pasha for treatment of postoperative nausea and vomiting. It is administered
orally 8mg twice a day. The release of serotonin from the enterochromaffin cells found in the
small intestine initiates a vomiting reflex through the initiation of the serotonin receptors,
therefore, blocking these receptors and inhibiting them prevents the vomiting reflex from taking
place. Ondansetron is absorbed from the gastrointestinal tract then it undergoes some limited first
pass metabolism. It has a bioavailability of approximately 50%-60 %.it has a volume of
distribution of approximately 160L. It is approximately 73% protein bound. When administered
orally, ondansetron is extensively metabolized and excreted in the urine and feces (Hendren,
Aponte-Feliciano & Kovac, 2015, pp 1753-1767). Its half-life is 3-4 hours.it has the following
adverse effects; lightheadedness, headache, dizziness, and tiredness. This is evidenced by Pasha
reporting excessive fatigue. The drug Interacts with some antibiotics such as clarithromycin.
Diclofenac is a non-steroidal anti-inflammatory agent indicated to Pasha as a mild analgesic.
Administered at a dosage of 50mg three times a day orally. Diclofenac is a potent inhibitor of
cyclooxygenase 1 and cyclooxygenase 2. (Patrignani & Patrono, 2015 pp 422-432). Diclofenac
inhibits prostaglandin synthesis in vitro. Prostaglandins are the ones which produce pain
therefore when inhibited, pain is reduced. It is highly protein bound. It normally undergoes
conjugation by glucuronidation and sulfation. Its elimination half-life is 1.2-2 hours. 40% of
diclofenac is excreted through the biliary excretion and 60% is excreted through the urine

elimination (Altman et al.2015, pp859-877). The common side effects when diclofenac is
administered are gastrointestinal bleeding, the client will present with abdominal pain, nausea,
vomiting and stomach ulceration. Diclofenac has got severe drug interactions with cidofovir and
ketorolac. It also has moderate interactions with other NSAIDs.
Lactulose is a non-absorbable sugar that is normally indicated to treat constipation
(MacFarlane, 2015 pp 52). It is administered 15 ml twice daily orally. This is because pasha has
not had his bowels open since the surgery and he is 3 days postoperatively. It is poorly absorbed.
lactulose metabolism is 100% in the colon by enteric bacteria. It has an elimination half-life of
1.7-2 hours. And is excreted through the feces. Its common side effects may include bloating and
cramps.
Pasha presented with nausea, frequent vomiting and mild dyspepsia. He also experiences
mild dyspepsia into his trunk and back. This is due to the side effects of some of the medications
administered. Morphine and paracetamol have synergistic effect, when administered together
they are more effective.
Medicines management
The essay will discuss about the mechanism of the action of the drugs administered. For an
effective therapeutic outcome, there are rights that the nurse administering the drug should
consider anytime he/she is about to administer a drug. The six rights that are to be considered
are; right patient, right medication, right dose, right time, right route and lastly, right
documentation (Smeulers et al 2014, pp 276-285). The nurse has a role in ensuring safe drug
administration. The nurse should be vigilant with the look-alike or sound-alike medications,

he/she should confirm if the medication label matches the order and with the one in the treatment
sheet. The nurse must ensure that the strength and dosage match the order and he/she should also
confirm the drug formulations and right dosage (Schellack, et.al pp.28-35). The nurse must
ensure that the administration time matches the order. Considering the right route, the nurse must
ensure that the route chosen for the drug administration matches the order. Lastly is the right for
documentation, which should be done immediately the nurse is done with the drug
administration.
Morphine is administered intravenously, paracetamol is administered orally, Ondansetron is
administered orally and diclofenac is administered orally. Advantages of the oral administration
are; the safest route, most convenient, relatively painless, does not a specialized staff for
administration and “slow release.” The disadvantages of the oral route are; unsuitable for the
unconscious patients, most of the orally administered drugs are absorbed slowly hence no rapid
action, it can lead to unpredictable absorption due to degradation by stomach enzymes.
Advantages of the intravenous route; the entire administered dose reaches the systemic
circulation immediately and therefore the drug can be accurately titrated against response
(Satoskar, Rege, & Bhandarkar, 2015). The disadvantages of the intravenous route are; it
requires a functioning cannula, it is more expensive and labor intensive compared to the other
routes, cannulation is distressing to some patients, cannulas are prone to infection and lastly, IV
injection of some drugs may cause local reactions.
The nurse’s role in education, support, and training for the patient is as follows; the nurse
should educate the client on the 6 Rs for safe medication. The nurse should involve the family
members to provide support to the client. And training the client on safe drug administration.
The nurse should be knowledgeable enough with the medication he/she intends to administer

(Dougherty & Lister, 2015.) should be aware of the immediate side effects of the drugs so that
he/she can teach the client. The nurse should be accountable and ready to stand in for his/role
whenever there is a need to. The nurse should be aware of her roles and should be in a position
to, perform them diligently without being forced (Bastable, 2017). He/she should be accountable
to the patients he is taking care of and be in a position to answer any changes to the patient. For
safe medication administration, the healthcare provider should use agency policy on Medication
Administration Record. The principles for pre-drug, peri-drug and post-drug administration are;
vigilance in medication preparation, checking for allergies, use of at least two patient identifiers
before administration, diligence in the medication calculations, avoidance of reliance on memory
instead use checklists and memory aids. Communicate with Pasha Smirnov before, during and
after the drug administration. Should ensure that the medication has not expired, be in apposition
to report or manage any adverse reactions that Pasha Smirnov would undergo. The nurse should
be alert to error-prone situations and high-alert medications. When Pasha Smirnov questions or
expresses a concern about a medication you are administering, stop and explore his concerns,
review the physician’s order and if necessary be in apposition to notify the practitioner who is in
charge of Pasha Smirnov the client.
The nurse should educate Pasha Smirnov on ways of preventing the deep vein thrombosis
from occurring. Ways of preventing deep vein thrombosis include; adhering the blood thinners
medication in this case Pasha Smirnov should adhere to Enoxaparin sodium, secondly, Pasha
should avoid standing still for long, keep on putting on the stockings, exercise regularly by
walking (Buttaro & Barba, 2012). He should follow any self-care measures to keep heart failure,
diabetes or any other health issues as stable as possible. Education on the drug side effects
should also be made known to Pasha Smirnov such that he is aware of the headache due to some

medication, the fatigue, and persistent nausea and vomiting. Pasha should speak out whenever
the signs and symptoms become adverse for further medical considerations. The nurse should
train Pasha Smirnov on how to do the subcutaneous drug administration and he should try it in
the right way to confirm that he is well conversant with the procedure. The nurse should also be
well conversant with the mode and route of drug delivery. The nurse should be aware that some
routes of drug administration have specific drug reactions.
Nursing care
While caring for Pasha Smirnov, post-operative pain management is the major. The nurse
caring for Pasha should, therefore, be able to assess and manage pain. This because the nurse has
frequent contact with the patient in a variety of settings. The nurses should be prepared to
perform a comprehensive and holistic pain assessment of the patient (Lewis et al. 2016). The
nurse should also initiate action to manage the pain, evaluate the effectiveness of the pain
management interventions and lastly, educate the patient. During the pain assessment, the nurse
should describe the location of the pain, the quality of the pain using the scaling where pain can
be ranged from a 0-10 where zero is no pain and 10 being the maximum. During the assessment,
the nurse should advise Pasha to describe the pattern of the pain, stating where it starts how it
travels up to where it ends. The nurse should request pasha to describe the relieving and the
exacerbating factors, what makes it worse and what makes it decreased. Lastly, the intensity of

the pain is found during the assessment, when is it mild and when is it bad? Such questions are
asked by the nurse to Pasha during the assessment. Secondly, is behavioral. Here the nurse
assesses pasha's response to stressors, pain expression behaviors, is Pasha exaggerating or is
genuine when told to scale the pain. Then the nurse also assesses the pasha's usual behaviors
prevented by the pain. Lastly, assess the social and pasha's community considerations on pain.
How do different genders from the community perceive pain? The measurement of pain is done
using tools which have been selected to their validity, reliability, and usability and are
recognized by pain specialists to be clinically effective in assessing acute pain. For adults, there
is a Numerical Rating Scale, visual analog scale, defense and veterans pain rating scale, adult
non-verbal pain scale, behavioral pain scale, and critical care observation scale (Park & Kim,
2014 pp 147-159). The nurse caring for pasha uses the numerical rating scale and rated Pasha’s
pain as moderating scale, 5-6 and therefore analgesics are administered to reduce the post-
operative pain to mild or no pain at all.
Safe practice and the nurse’s role
The type of pain that Pasha experiences is nociceptive pain. Nociceptive pain arises from the
damaged tissue reported to the brain by the nervous system. Nociceptive pain typically changes
with movement and position (Tsay et al, 2015 pp 221-232). Pasha repots a moderate pain scaled
5-6 while in mobile whereas the pain reduces to 2-3 when seated. His pain changes with position.
Pain assessment tools can be divided into; self-reporting intensity tools including the Numeric
Rating Scales, Verbal Descriptive Scale, Faces Pain Scale and Visual Analogue Scale. Verbal
descriptive scale requires the patient interpret and express their pain in verbal form. Secondly are
pictorial pain scales which include Faces Pain Scale and Wong-Baker faces Pain Scale. Pictorial
pain scales consist of series of progressively distressed facial expressions. The patient chooses

the face that represents the severity or intensity of the current pain. Thirdly we have the visual
analogue scale, Mc Gill Pain Questionnaire and lastly is the pain interview.
Nursing roles for assessing, managing and evaluating effectiveness of pain management
include the following; determining the nature, location and severity of the pain. Identifying
factors that affect the resident’s perception and expression of pain. Determining when to
administer the analgesics for pain relief. The nurse has also a role in deciding which analgesic to
administer if more than one is ordered, determining the dose of the analgesic medication to
administer if a range is prescribed. The nurse evaluates the effectiveness of the analgesic
administered, assesses and manage the side effects of the medication administered. A nurse
determines why the analgesic was ineffective, if applicable like in the case with Pasha whereby
some analgesics were administered but still the pain is persistent. The nurse uses nursing
interventions to promote comfort and relieve pain. Lastly the nurse documents pain assessment
and intervention noted herein to reflect use of the nursing process.
Pasha’s pain was managed medically. Analgesic medications were administered including
paracetamol but the pain was still persistent. The nurse should therefore continue administering
the analgesics until pasha is pain free. The nurse should use the “Analgesic pain ladder” which
was developed by the WHO to manage chronic pain (Malec, & Shega, 2015 pp 337-350). It
requires that when pain occurs there should be prompt oral administration of drugs starting with
non-opioids analgesic, then strong opioids such as codeine and then strong opioids such as
morphine until the patient is free of pain.
The NMC 2015 code outlines four domains; professional values, communication and
interpersonal skills and decision making and lastly the fourth domain which talks of leadership,
management and team working in the health care practice (Standing, 2015). The code outlines

the professional standards of practice and behavior for nurses, midwives and nursing associates.
Basically, the code prioritizes patients, practicing effectively, preserving the patient’s safety and
promoting professionalism and trust.
In conclusion, pasha who was initially diagnosed with severe osteoarthritis experienced
persistent and severe hip joint pain. He underwent a right total hip replacement. After the
surgery, Pasha experienced postoperative pain. Pasha's post-operative pain is, managed
medically and therefore the nurse should be well conversant with the six rights for a safe
medication. Lastly the nurse should be aware of her role in pain management, to be in a position
of alleviating Pasha’s post-operative pain.

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