1. Running head: ATENOLOL 1
Atenolol
Caitlyn Cloy
Hardin-Simmons University
Pharmacology
NURSE 3423
Lisa Van Cleave, MSN, RN
December 6, 2013

2. ATENOLOL 2
Introduction
“Atenolol (Tenormin), a selective beta1-blocker, is one of the most frequently prescribed
drugs in the United States…” (Kee, J.L., Hayes, E.R., & McCuistion, L.E., 2012, p. 265).
In an attempt to expand my study of pharmacology, I will provide an assessment of the
drug atenolol. I will specify the pharmacodynamics, pharmacokinetics, adverse/side
effects, and the nursing implications associated with atenolol in hopes to better my
understanding of atenolol and pharmacology as a whole.

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Atenolol
Atenolol has the brand name of Tenormin and belongs to the beta1-adrenergic
blocker class. Typically, atenolol is prescribed to patients with hypertension to lower
blood pressure by decreasing heart rate. Other uses for atenolol can be to treat angina
pectoris or to decrease the risk of myocardial infarction. The typical dosage of atenolol
for an adult patient is 50-100 mg per day, and 25-50 mg per day for older adults. The
route of administration is by mouth or intravenously. Simply stated, atenolol selectively
blocks beta1-receptor sites by inhibiting catecholamine binding and decreasing the renin-
angiotensin-aldosterone system. As a result, heart rate drops, followed by a decrease in
blood pressure. Once ingested orally, atenolol is 50% absorbed in the gastrointestinal
tract, and is excreted in the urine and feces. Atenolol reaches its onset of action within 1
hour, and reaches its peak action in 2-4 hours. It is important to be aware of the drug
interactions with atenolol, such as with non-steroidal anti-inflammatory drugs that result
in decreased hypotensive effects. Also, side effects associated with atenolol could
include dizziness, drowsiness, depression, nausea, diarrhea, leg pain, decreased libido,
and cool extremities. Adverse reactions could include, hypotension, hypoglycemia,
bradycardia, headache, and bronchospasm (Kee, J.L., Hayes, E.R., & McCuistion, L.E.,
2012, p. 266). As a nurse, it is essential to be educated in many aspects of pharmacology.
Through my study of atenolol I will strive to gain more knowledge about this drug and
use the obtained information to guide me as I encounter other medications in the future.
Pharmacodynamics
Like other beta1-adrenergic blockers, atenolol blocks neurotransmitter receptor
sites, causing a result of decreased peripheral vascular resistance, stroke volume, heart

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rate, and blood pressure (Kee, J.L., Hayes, E.R., & McCuistion, L.E., 2012, p. 265). In
order to achieve these effects, atenolol must first be absorbed either orally or
intravenously. When taking atenolol by mouth, onset of action will begin in
approximately 1 hour and will reach its peak blood plasma concentration in 2 to 4 hours
(Deglin, Vallerand, & Sanoski, 2010, p. 189). The Asian Journal of Pharmaceutical and
Clinical Research (2013) states that “conventional tablets of atenolol have been reported
to exhibit fluctuation in the plasma drug levels, resulting either in manifestations of side
effects or reduction in drug concentration at the receptor site” (Kumare, Marathe,
Kawade, Ghante, & Shendarkar, 2013, p. 83). If taken intravenously, atenolol will reach
its peak in 5 minutes, although its onset of action is unknown. Both routes will allow the
medication to remain in the body for 24 hours (Kee, J.L., Hayes, E.R., & McCuistion,
L.E., 2012, p. 266). It is important to be aware of the pharmacodynamics of atenolol, as
well as other medications, in order to prevent drug toxicity as well as ensure the drug is
within its therapeutic window of effectiveness.
Pharmacokinetics
The pharmacokinetics of atenolol are important for the patient and the provider to
be aware of. Pharmacokinetics is “the process of drug movement to achieve drug
action.” The first step in the pharmacokinetic process is absorption, the process where
the drug is moved from one area to another (Kee, J.L., Hayes, E.R., & McCuistion, L.E.,
2012, p. 4). Atenolol is absorbed by passive diffusion in the gastrointestinal tract (p.
265). Passive absorption means that in order for the drug to be absorbed no energy is
required (p. 4). Atenolol is also hydrophilic meaning that is follows water and tends to be
dissolved in water. During the absorption stage, it is also important to be aware of the

5. ATENOLOL 5
bioavailability of atenolol, which is 50% (p. 265). This means that the body will use 50%
of the drug administered. Next, in the distribution phase, the drug becomes available to
be used by body tissues (p. 5). In this stage, 6-16% of atenolol binds to proteins, leaving
the rest free to be utilized, creating a pharmacologic response (p. 266). Once the free
drug begins to deplete, the protein-bounded drug is released allowing for more “free
drug” to be effective in the body (p. 5). Following distribution is the metabolism phase.
Drugs are transformed and cause changes in the body during this stage. An important
aspect of the metabolism phase is a drug’s half-life, or the “time it takes for one half of
the drug concentration to be eliminated” (p. 6). Atenolol has a half-life of six to seven
hours (p. 266). Finally, the last stage of the pharmacokinetic process is excretion. In
order for a drug to be effective, it must be taken in, used, and then eliminated. The main
route of excretion is typically through the kidneys and GI tract (p. 6). This is true with
atenolol; the drug waste products are eliminated through the urine and feces (p. 266).
Side Effects and Adverse Effects
All beta-adrenergic blockers have similar side effects and adverse effects because
of their mechanism of action. Beta-adrenergic blockers block the effects of the
adrenergic neurotransmitters norepinephrine and epinephrine (Kee, J.L., Hayes, E.R., &
McCuistion, L.E., 2012, p. 265). Specifically, atenolol antagonizes the adrenergic
neurotransmitters by “inhibiting catecholamine binding with beta-adrenergic receptor
sites” (p. 265). This blocking allows for the parasympathetic nervous system to take
over, creating a cholinergic response. These responses correlate with the side effects of
adrenergic blockers. The most common side effects of atenolol are drowsiness,
dizziness, fainting, depression, weakness, nausea, vomiting, diarrhea, cool extremities,

6. ATENOLOL 6
and leg pain (p. 266). Dizziness and headache may occur in about 5% of atenolol-taking
patients. Patients should be cautioned to avoid driving or other activities requiring
alertness until response to the medication in known. Dizziness and fainting can also be
associated with orthostatic hypotension. Patients taking atenolol should be warned to
taking caution when changing positions. Nausea, vomiting, and diarrhea are common
side effects for many medications because of the possibility of gastrointestinal upset
caused by the chemical makeup of the medication (Casco, 2010). Since atenolol
decreases blood pressure, there is a possibility that blood flow to the extremities could be
compromised. This results in cold extremities. Weakness and leg pain are symptoms
that are also related to the amount of blood flow reaching the tissues. Along with side
effects, there are also serious adverse reactions that can result from the use of atenolol.
Adverse effects of atenolol are hypotension, bradycardia, heart failure, and the masking
of hypoglycemia. Also life-threatening adverse effects of atenolol are bronchospasm,
pulmonary edema, and dysrhythmias (Kee, J.L., Hayes, E.R., & McCuistion, L.E., 2012,
p. 266). Because atenolol decreases heart rate and blood pressure there is a risk for
hypotension, or blood pressure that is too low. Livestrong.com (2010) says that 10% of
people taking atenolol may experience hypotension. Like hypotension, bradycardia can
also occur as a result of a decrease in heart rate. Atenolol can mask the effects of
hypoglycemia, so diabetics should take caution and check blood sugar frequently when
taking atenolol (Casco, 2010). These adverse reactions are not desired and it is crucial
that health care providers and nurses be aware of the potential for the following life-
threatening reactions caused by atenolol. First, bronchospasms can constrict the airways
and prevent adequate inspiration and expiration, resulting in hypoxia. Because of the risk

7. ATENOLOL 7
of bronchospasm, atenolol should be used carefully in COPD patients (Cochrane, Quinn,
Walters, Young, 2012). Also, dysrhythmias can be deadly because of altered heart
rhythm, resulting in poor cardiac output (Kee, J.L., Hayes, E.R., & McCuistion, L.E.,
2012, p. 266). It is important to recognize when side effects or adverse effects are
occurring, especially when they have the potential to be life-threatening.
Nursing Considerations
It is important that nurses are aware of the special considerations that accompany
certain drugs in order to maintain patient safety and medication effectiveness. This can
include assessment techniques, implementation, awareness of contraindications and
precautions, and client teaching. When administering atenolol there are specific
assessments that should be performed. Because of the nature of atenolol it is important to
monitor blood pressure, EKG, pulse, input & output, and weight before and during
therapy. Be cautious of changes in weight, edema, dyspnea, and jugular distention
because these signs can indicate heart failure. If atenolol is being given for angina, assess
for frequency and severity of chest pain. Always assess for indications of adverse side
effects during therapy (Deglin, Vallerand, & Sanoski, 2010, p. 190). Nurses should be
aware that beta-blockers like atenolol can cause, “transient increases in serum lipid and
glucose levels.” In relation, beta-blockers can mask hypoglycemic symptoms, so special
consideration should be made for diabetic patients. Finally, assess patients with chronic
lung disease or asthma for exacerbation of symptoms during therapy (Dumont &
Hardware, 2009). Nurses should be aware of changes in lung sounds, dyspnea, or other
signs of difficulty breathing that could indicate bronchospasm, which can be seen in
patients with COPD (Cochrane, Quinn, Walters, Young, 2012). When implementing

8. ATENOLOL 8
atenolol therapy, nurses should take an apical pulse before administration. If the pulse is
less than 50 beats per minute, the medication should be withheld and the health care
provider should be notified. Nurses should be alerted when a contraindication is
observed and should know what other comorbidities raise caution when combined with
atenolol. Atenolol therapy is contraindicated in patients with heart failure, pulmonary
edema, and in patients in cardiogenic shock, or who have bradycardia. Use atenolol
cautiously in patients with pulmonary disease, hepatic impairment, renal impairment,
diabetes, thyrotoxicosis, and in geriatric or pregnant patients. When providing patient
teaching, there are important considerations that the patient should be aware of. First,
patients should be guided to always follow the directions given by the physician and to
never skip a dose. Skipping a dose or abrupt withdrawal can result in life-threatening
arrhythmias and heart attack. Patients should be advised to carry identification stating the
medication and disease process, and to always make sure enough mediation is on hand.
It is also important that patients are taught how to monitor their own blood pressure and
pulse. Nurses should go over the side effects of atenolol and provide warnings like not
changing positions too quickly, or to avoid driving until medication response is known.
Also nurses should reinforce the need to adhere to medication therapy as well as other
therapies to lower blood pressure like exercise and diet restrictions (Deglin, Vallerand, &
Sanoski, 2010, p. 190). Finally, nurses, alongside doctors, should acknowledge research
on the use of beta-blockers, for example, in cases where atenolol is used in stable patients
with coronary artery disease (Steg, Ferrari, Ford, Greenlaw, Tardif, Tendera, Abergel &
Fox, 2012). Acknowledging research and implementing evidence based practice is key in
providing high quality of care for patients in any circumstance. Nurses should be aware

9. ATENOLOL 9
of the specific considerations of atenolol in order to provide safe, knowledgeable
administration and correct patient teaching.
Conclusion
Tenormin, better known as atenolol, is indicated in patients with hypertension,
angina pectoris, and to manage definite or suspected myocardial ischemia. This drug is
commonly used in the United States and it is important that nurses be familiar with
atenolol in order to administer it safely and effectively. After studying the
pharmacodynamics, pharmacokinetics, side effects, adverse effects, and nursing
considerations, I feel much more knowledgeable about this drug. Not only does this
information help me understand atenolol, it also helps me recognize the importance of
being educated in pharmacology. When you realize all the information that is associated
with atenolol you see that all other medications have a great deal of information that
should be addressed. I believe this study of atenolol will help me in my career as a future
nurse as it has set a foundation and standard for the type of educated care I will strive to
provide.

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References
Casco, K. (2010, March 23). Atenolol beta-blocker side effects. Retrieved from
http://www.livestrong.com/article/92609-atenolol-beta-blocker-side-effects/
Cochrane, B. B., Quinn, S. S., Walters, H. H., & Young, I. I. (2012). Investigating the
adverse respiratory effects of beta-blocker treatment: six years of prospective
longitudinal data in a cohort with cardiac disease. Internal Medicine Journal,
42(7), 786-793. doi:10.1111/j.1445-5994.2011.02563.x Retrieved from
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4876-a39c-80454cf072b1%40sessionmgr110&vid=4&hid=4203
Deglin, J., Vallerand, A. & Sanoski, C. (2010). Davis’s Drug Guide for Nurses (11th ed.).
Philadelphia: F.A. Davis.
Dumont , C., & Hardware, J. (2009). Teaching patients to tame their hypertension.
American Nurse Today, (July/August), Retrieved from
http://www.americannursetoday.com/Article.aspx?id=5816
Kee, J.L., Hayes, E.R., & McCuistion, L.E. (2012). Pharmacology: A nursing process
approach. (7h ed.). St Louis: Saunders.
Kumare, M. M., Marthathe, R. P., Kawade, R. M., Ghante, M. H., & Shendarkar, G. R.
(2013). Design of fast dissolving tablet of atenolol using novel co-processed
superdisintegrant. Asian Journal Of Pharmaceutical & Clinical Research, 6(3),
81-85. Retrieved from
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Steg, G., Ferrari, R., Ford, I., Greenlaw, N., Tardif, J., Tendera, M., Abergel, H., & Fox,
K. M. (2012). Heart rate and use of beta-blockers in stable outpatients with
coronary artery disease. PLOS One, doi: 10.1371/journal.pone.0036284
Retrieved from
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.003628
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