Pharmacology of Oral Beta Blockers for Hypertension Treatment

This presentation discusses the pharmacology of oral beta blockers used to treat hypertension, including pathophysiology, pharmacokinetics, mechanisms of action, adverse effects, and contraindications. It explores three medications in this classification and potential interactions with other drugs and foods.

Running head: PHARMACOLOGY
PHARMACOLOGY
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As we all know that pharmacology is a branch of medicine that is concerned regarding the uses,
effects and the modes of actions of different drugs. Hence, in this presentation we will discuss
about the pharmacology of the oral Beta blockers that is used to treat hypertension in patients.
 Pathophysiology
Hypertension can be considered as the chronic elevation of the blood pressure that is responsible
for the long term end organ damage resulting in increased morbidity and mortality in patients
(Rienstra et al., 2012). It is normally manifested by the systolic blood pressure (SBP) > 140
mmHg or diastolic blood pressure (DBP) > 90 mmHg. Patients having arterial hypertension can
have an augmented cardiac output and increase in the systemic vascular resistance. In the older
patients increased stiffness of the vasculature and systemic vascular resistance causes
hypertension. Increase in the cytosolic calcium in the vascular smooth muscles can cause
vasoconstriction leading to high blood pressure (Rienstra et al., 2012).
• Pharmacokinetics (ADME)
Some of the Beta blockers are lipophilic and are well absorbed from the gut. They are
metabolized using the first pass metabolism. Since some of them are lipophilic and hence they
have short half-lives. In case of the hydrophilic beta blockers like atenolol, nadolol, sotalol
undergo a negligible first pass metabolism.
• Mechanisms of action of medication (pharmacodynamics)
Beta blockers work in hypertension by blocking the action of the endogenous catecholamine on
the beta-adrenergic receptors, part of the sympathetic or the autonomic nervous system. The beta
blockers either blocks the activation of all kinds of beta-adrenergic receptors or selectively the

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β1, β2 and β3 receptors. The intrinsic vasodilator property of the beta- blockers prevents the
vasoconstriction and ensure blood flow through the arteries.
• Adverse effect/s of medication
Several adverse effects are related to the beta blockers. The general adverse effects related to the
beta blockers are diarrhea, nausea, hypotension, cold extremities, worsening of the Reynaud’s
syndrome, bradycardia, fatigue, dizziness and modified glucose and lipid metabolism. Some of
the lipophilic Beta –blockers can penetrate the blood brain barrier causing insomnia. The Beta
blockers can increase the tri-glyceride levels and the lower the concentration of the high density
cholesterol (HDL). Uptake of the non-selective beta blockers might give to bronchospasms.
• Contraindications (people who should not take this medication)
Bradycardia
Beta blockers should not be used in patients with Bradycardia (heart rate fewer than 60 beats per
minute) as patients might experience chest pain, light headedness, fatigue and the weakness on
administering the beta blockers (Salles et al., 2013).
Asthma
One of the action of the Beta blockers is that they constrict the airways, which can trigger
asthmatic attacks.
Diabetes
Beta blockers might cause a delayed response to hypoglycemia in diabetic patients. The beta
blockers blocks the release of insulin by the interaction with the nerve signals to the pancreas.

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• 3 medications in your chosen classification (generic and trade name)
Acebutolol (Sectral)
Metoprolol (Lopressor, Toprol XL)
Propranolol (Hemangeol, Inderal LA, Inderal XL, InnoPran XL)
• Potential interactions of this medication classification with other drugs / foods
Acetabutolol –
Acetabutolol might interact with the other drugs for asthma, allergy, cold, diabetes or the
migraines, diet pills, medications for high blood pressure like reserpine, Nonsteroidal anti-
inflammatory drugs (NSAIDs), Advil or Motrin (ibuprofen) and Indocin (indomethacin).
Alcohol might worsen the adverse effects of acetabutolol. It also might interact with the
potassium rich food and some herbs, caffeine (Först et al., 2012).
Metoprolol –
Some of the drugs that can interact with Metoprolo are antidepressants like bupropion and
paroxetine, antimalarial drugs such as hydroxychloroquine, some antihistamines like Benadryl,
certain HIV drugs like Ritonavir, antifungals like Terbinafine and other medications used to treat
heart burns such as cimetidine and ranitidine (Först et al., 2012). Alcohol should be avoided
while talking Metoprolol. Metoprolol taken with multivitamin medicines might decrease its
effects hence the administration time of the medicines should be separated by at least 2 hours
(Först et al., 2012).

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.
Propranolol-
Alcohol should be avoided during the treatment regimen. Propanolol and alcohol might have a
combined effect in lowering the blood pressure and hence a person might face light headedness
dizziness and changes in the heart rhythm (Wiysonge et al., 2013). Propranolol should not be
taken together with agents that affect the catecholamines. Aluminium hydroxides,
anticholinergics, chlorpromazine, drugs affecting the liver enzymes, some heart medications like
digoxin and disopyramide . The medications might also interact with some of the laboratory tests
like the glaucoma screening test, cardiovascular stress testing).

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References
Först, G., Cwiklik, L., Jurkiewicz, P., Schubert, R., & Hof, M. (2014). Interactions of beta-
blockers with model lipid membranes: molecular view of the interaction of acebutolol,
oxprenolol, and propranolol with phosphatidylcholine vesicles by time-dependent
fluorescence shift and molecular dynamics simulations. European Journal of
Pharmaceutics and Biopharmaceutics, 87(3), 559-569.
Rienstra, M., Damman, K., Mulder, B. A., Van Gelder, I. C., McMurray, J. J., & Van
Veldhuisen, D. J. (2013). Beta-blockers and outcome in heart failure and atrial
fibrillation: a meta-analysis. JACC: Heart Failure, 1(1), 21-28.
Salles, G. F., Cardoso, C. R., Fonseca, L. L., Fiszman, R., & Muxfeldt, E. S. (2013). Prognostic
significance of baseline heart rate and its interaction with beta-blocker use in resistant
hypertension: a cohort study. American journal of hypertension, 26(2), 218-226.
Wiysonge, C. S., Bradley, H. A., Volmink, J., Mayosi, B. M., & Opie, L. H. (2017). Beta-
blockers for hypertension. The Cochrane Database of Systematic Reviews, (1),
CD002003. Advance online publication. http://doi.org/10.1002/14651858.CD002003.pub5