Pharmacology Case Study: Asthma, GERD, and Depression

This case study discusses the pharmacology of drugs used to treat asthma, GERD, and depression in a patient. It also includes information on St. John's Wort and herbal medicine. Patient assessment and education are also covered.

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Pharmacology Case Study
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Introduction
Different disease processes demand different considerations in clinical assessment and
drug administration. The treatment of these diseases requires a choice of drugs that are
efficacious in combating the ailments while minimizing harmful outcomes. The current paper is
a discussion on drug pharmacology in reference to a case study of a patient requiring therapeutic
intervention. The patient, Sally Smith is a 36-year-old patient with a history of asthma and
GERD on albuterol inhaler prn, loratadine 10 mg PO daily, omeprazole 20 mg PO twice daily
and Yasmin. She also reports using St John’s Wort 1 tablet PO daily for episodes of depression.
The paper will outline the pathophysiology of her disorders, Asthma, GERD, and depression, to
better understand the relevance of the chosen medications and their pharmacodynamics.
Concerning herbal preparations, the paper will outline current research on its
pharmacodynamics, efficacy, potential risks and advantages of using them. The
pharmacokinetics, adverse effects, prescriber considerations and patient education for each drug
will be outlined.
Pathophysiology.
Asthma
Asthma is a chronic airway disease. The main features are bronchoconstriction, airway
remodeling and symptoms of wheezing and cough. This is usually as a response to
environmental stimuli and allergens such as animal dander, pollen, dust, food among others
(Kumar, Abbas & Aster, 2015). Exposure to an allergen leads to a Th2 mediated immune
response with the production of IgE antibodies, the classic type 1 hypersensitivity reaction. Re-
exposure to the antigen leads to antibody crosslinking on mast cells and mast cell degranulation

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releasing inflammatory mediators, cytokines, and histamine. Loratadine is an antihistamine drug
that works to block the effects of histamine in the disease process. Mast cell degranulation drives
the early phase causing excess mucus production due to mucosal hyperstimulation, dilatation of
vessels and a direct effect on vagal receptor causing bronchoconstriction (Kim, Kim, Jeon, &
Kim, 2013). Albuterol is a selective beta agonist that acts on bronchial smooth muscle to cause
bronchodilation hence reversing the pathologic bronchoconstriction and wheeze. The late phase
includes the recruitment of polymorphonuclear lymphocytes that drive a chronic inflammation
leading to smooth muscle hypertrophy, deposition of collagen and mucosal gland hypertrophy
(Kumar, Abbas & Aster, 2015). This is termed airway remodeling.
Gastro-esophageal reflux disease
GERD is a condition characterized by the reflux of gastric contents into the esophagus
due to incompetent lower esophageal sphincters. The disease predisposes the patient to irritative
acidic contents of the stomach (Kumar, Abbas & Aster, 2015). Unlike the gastric mucosa, the
mucosa of the esophagus is stratified squamous epithelium which is not adapted to contact with
acidic contents (Kumar, Abbas & Aster, 2015). The reflux occurs when the lower esophageal
pressures are lower than the intragastric pressure such as in transient relaxation of the sphincter
or a hiatal hernia. Treatment modalities are aimed at preventing further reflux, preventing erosive
esophagitis and reducing other complications (Katz, Gerson, & Vela, 2013). The patient is on
omeprazole, a proton pump inhibitor which aids in symptomatic relief by controlling acid
production from gastric glands.
Depression.

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Depression is a complex disorder resulting from an interplay of environmental, genetic
and psychosocial factors (Sadock, Sadock, & Ruiz, 2014). The biochemical theories of
depression suggest an impaired bioamine balance in the brain. They propose that the
neurotransmitters serotonin, dopamine, GABA, and norepinephrine reduced in their respective
neurotransmitter systems (Sadock, Sadock, & Ruiz, 2014). The mainstay of treatment of
depression is focused on restoring or increasing these neurotransmitter concentrations.
St John’s Wort in the Management of Depression
Efficacy
St John’s Wort (Hypericum perforatum) is a botanical herb that has been used to treat
various conditions. It is a commonly prescribed antidepressant and has been shown in trials to be
superior to placebo and as efficacious as the other standard antidepressants in the treatment of
mild to moderate depression (Coppock & Dziwenka, 2016). Its efficacy has been shown to be
equal to standard antidepressants as seen in the current clinical trials (Sarris, 2013).
Chemistry
Hypericum has many active ingredients depending on extraction methods. The most
relevant include Hypericin, hyperforin, biapigenin, amentoflavone, hyperoside, pseudohypericin,
rutin, quercetin, and miquelianin (Sarris, 2013). Other chemicals are extracted from but are not
of pharmacologic importance.
Pharmacology
The pharmacodynamic properties of this herb are complex and still being researched.
Hyperforin has been shown to block the reuptake of multiple neurotransmitters while

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amentoflavone has been shown to inhibit binding at different serotonin and dopamine receptors
(Coppock & Dziwenka, 2016). The mode of action of this formulation has thus been attributed to
inhibition of reuptake of serotonin, dopamine, and noradrenaline with activation of GABA and
glutamate receptors.
Adverse Effects and Drug Interactions
St John’s Wort is relatively safe. In clinical trials comparing it with traditional
antidepressants, it was not associated with any serious adverse effects. minor side effects were
reported including nausea, vomiting, palpitations, fatigue, dry mouth, restlessness and increased
anxiety. Photosensitivity is the most common side effect at higher doses (Sarris, 2013).
Drug interactions with this medication do occur. The most serious is the development of
serotonin syndrome when combined with selective serotonin reuptake inhibitors for the
management of depression. This is attributed to increased serotonin concentration as both drugs
block serotonin reuptake (Coppock & Dziwenka, 2016). Other drug interactions noted included
an induction in CYP 3A4 that has the potential to reduce the circulating half-life of some drugs
such as oral contraceptives. Important prescriber considerations are caution in prescribing this
drug with SSRIs as it can cause serotonin syndrome and with oral contraceptives as it has been
shown to cause breakthrough bleeding (Coppock & Dziwenka, 2016). It is also contraindicated
in bipolar disorder as it causes mania in those patients.
Herbal Medicine
The continued use of herbal medicine is attributed to the notion of it being organic,
natural and safer than the factory made synthetic medication. However, this comes at a cost as
some of the herbal remedies are experimental and their efficacy has not been proven (Baradaran,

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2017). It could further delay treatment for a condition that could be life-threatening with standard
modes. Those using herbal remedies are encouraged to use with caution, use those herbal
products that have been proven to have a role in the management of their disorder and also
receive the medication from a licensed institution (Bone & Mills, 2013).
Pharmacokinetics and adverse effects of the chosen regiment.
Albuterol
Albuterol is a selective beta 2 agonist administered as a powder through the inhalational
route or per oral (Katzung, Masters, & Trevor, 2015). It has a half-life of 1.6 hours. Systemic
absorption is rapid following inhaled administration. It is not highly protein bound. It is
metabolized by hydrolysis with esterases and conjugation to salbutamol 4’- 0- sulfate. It is
excreted in urine in, 72% in 24 hours. 44% of it as a metabolite and 28% unchanged.
Albuterol is relatively safe when used appropriately. However, the following side effects
can present nervousness, weakness and skeletal muscle tremors, bronchospasm and
hypokalemia. Drug interactions include beta-blockers which block the effects of albuterol,
diuretics that may potentiate or worsen hypokalemia and digoxin which is reduced in serum
(Katzung, Masters, & Trevor, 2015).
Loratadine
Loratadine is an H1 antihistamine available as oral tablets. It is rapidly absorbed
following oral administration with a 40 % bioavailability. It is 99% protein bound with a half-life
of 8.4 hours with a peak effect in 2 hours. It is metabolized in the liver by CYP 34A to an active
compound descarboethoxyloratadine with a half-life of 27 hours. It is excreted in urine as
conjugates (40%) a similar amount in feces (Katzung, Masters, & Trevor, 2015).

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Loratadine causes less sedation and agitation than the other antihistamines. Other side
effects include a headache, dry mouth, urinary retention, blurred vision, nausea, and vomiting.
The antimuscarinic adverse effects require monitoring to prevent adverse outcomes. CYP 3A4
inhibitors such as cimetidine, ketoconazole, and erythromycin increase its plasma levels hence
these drug interactions should be monitored (Katzung, Masters, & Trevor, 2015).
Omeprazole
Omeprazole is a proton pump inhibitor available as an oral tablet. It is absorbed in the
small intestine within 3 to 6 hours with a 30% bioavailability that increases to 60% on a repeate
dose. It has a half-life is less than 1 hour and it is cleared within 3 hours. Its volume of
distribution is 0.3 liters/kg. it is metabolized completely in the liver with 80% of the metabolites
excreted in urine and the remaining in bile (Katzung, Masters, & Trevor, 2015). Clearance of
diazepam and phenytoin is increased when given with omeprazole.
Adverse effects include a headache, dizziness, diarrhea, vomiting, nausea, flatulence and
abdominal pain. A serious associated adverse reaction is acute interstitial nephritis that
necessitates drug monitoring (Katzung, Masters, & Trevor, 2015).
Yasmin
Yasmin is an estrogen/progesterone oral contraceptive pill containing drospirenone and
ethinyl estradiol. Bioavailability is 76% after a single tablet. Absorption was slower in fed
individuals. It is 97% protein bound to serum proteins. The two are metabolized to a minor
extent by the liver.
Adverse effects include premenstrual syndrome, headache, breast tenderness, nausea and
vomiting, abdominal pain and mood changes. Drug interactions include drugs that inhibit or

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induce the cytochrome enzymes CYP3A4 (Katzung, Masters, & Trevor, 2015). They may reduce
the effectiveness or cause breakthrough bleeding.
Patient Assessment and Education.
The assessment in this patient will include a full blood count, liver function tests, urea
and electrolytes and blood gas analysis. These are the routine tests that help rule out infections,
check liver functions, renal functions and metabolic status of the patient as shown by her
presentation. They also guide pharmacologic choice for example drugs that are metabolized by
the liver need good hepatic function. The other tests include lung function tests for obstructive
airway disease such as Asthma and a chest radiograph.
The patient should be educated on drug compliance and vigilance concerning adverse
effects. Drug compliance is among the main causes of treatment failure especially for patients
with chronic illnesses such as Sally (Párraga, López-Torres, Villena, Morena, & Escobar, 2014).
Her drug regiment presents a possibility of various adverse reactions and she should be educated
on the early recognition of such signs and to seek medical help if any is noted.
Conclusion
Patient assessment and choice of medication are often interlinked. The current case study
on Asthma, GERD and depression presented several drugs combinations that were discussed.
They included albuterol, omeprazole, Yasmin, and loratadine. Their pharmacodynamics and
pharmacokinetics prove their choice in this patient. St John’s Wort, a herbal medicine was also
discussed, showing that herbal extracts can be as efficacious as standard antidepressants.

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References
Baradaran, A. (2017). Administration of herbal drugs in geriatric individuals; trends on its helps
and hazards. Geriatrics Persia, 1(1).
Bone, K., & Mills, S. Y. (2013). Principles and Practice of Phytotherapy, Modern Herbal
Medicine, 2: Principles and Practice of Phytotherapy. Elsevier Health Sciences.
Coppock, R. W., & Dziwenka, M. (2016). St. John’s wort. In Nutraceuticals (pp. 619-631).
Katz, P. O., Gerson, L. B., & Vela, M. F. (2013). Guidelines for the diagnosis and management
of gastroesophageal reflux disease. The American journal of Gastroenterology, 108(3),
308.
Katzung, B. G., Masters, S. B., & Trevor, A. J. (2015). Basic & clinical pharmacology (12th
ed.). New York; New Delhi: Tata McGraw-Hill education.
Kim, Y. M., Kim, Y. S., Jeon, S. G., & Kim, Y. K. (2013). Immunopathogenesis of Allergic
Asthma: More Than the Th2 Hypothesis. Allergy Asthma Immunol Res, 5(4), 189-196.
Kumar, V., Abbas, A. K., & Aster, J. C. (2015). Robbins and Cotran pathologic basis of disease.
(Ninth edition.). Philadelphia, PA: Elsevier/Saunders
Párraga, I. M., López-Torres, J. H., Villena, A. F., Morena, S. R., & Escobar, F. R. (2014).
Adherence to patient’s antidepressant treatment and the factors associated with non-
compliance. Atencion Primaria, 46(7), 357-366.
Sadock, B. J., Sadock, V. A., & Ruiz, P. (2014). Kaplan & Sadock’s synopsis of psychiatry:
Behavioral sciences/clinical psychiatry (11th ed.). Philadelphia, PA: Wolters Kluwer

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Sarris, J. (2013). St. John's wort for the treatment of psychiatric disorders. Psychiatric
Clinics, 36(1), 65-72.