Propranolol Pharmacology

On this episode, I discuss propranolol pharmacology, adverse reactions, and important drug interactions you should know. Propranolol (Inderal) is a non-selective beta-blocker. There are many indications for it including hypertension, tachycardia, atrial fibrillation, post-MI, chronic stable angina, essential tremors, migraine prophylaxis, esophageal varices, performance anxiety disorder, lithium-induced tremor, psychotic induced akathisia, and thyroid storm. Propranolol blocks beta-1 receptors that are commonly referred to as the cardiac receptors and beta-2 receptors that are in the lungs. Albuterol is a beta-2 agonist meaning that propranolol can block its effects. This may lead to bronchospasms and worsening of respiratory conditions. This is one of the major issues when using a non-selective beta-blocker vs a selective one. Other adverse effects include a drop in blood pressure and pulse. Fatigue is also seen in many geriatric patients so it is important to be titrating them up slowly. If you notice patients increasing caffeine intake, starting a stimulant, or experiencing new depression symptoms that can be a sign of fatigue. Sexual dysfunction has also been seen in patients taking propranolol. Propranolol may mask symptoms of hypoglycemia. Closely monitor patients that are taking insulin and/or sulfonylureas. Abrupt discontinuation can increase the risk for acute coronary syndromes, especially if the patient is already at risk. Make sure that the medication is taken consistently and there aren’t periods of multiple missed doses. Propranolol comes in multiple dosage forms that have been mixed up. When dispensing or administering take extra caution that the medication is correct. Propranolol is a weak CYP1A2 inhibitor that could increase concentrations of tizanidine or theophylline. Propranolol also gets broken down by CYP1A2. Medications that inhibit this enzyme can increase the concentration of propranolol. Examples of these are ciprofloxacin and fluvoxamine. Inducers of CYP1A2 can reduce concentrations. These are rifampin, carbamazepine, and phenobarbital. A unique CYP1A2 inducer is smoking tobacco. Medications can cause additive effects when it comes to blood pressure and pulse. Be careful with any blood pressure-lowering medications including antihypertensives, PDE5 inhibitors (sildenafil), and Parkinson’s medications (Sinemet). Drugs that can lower pulse include centrally acting alpha 2 antagonists (clonidine) and acetylcholinesterase inhibitors (donepezil, rivastigmine).

Om Podcasten

Pharmacology is one of the most challenge topics you will encounter as a healthcare professional, but it can be the most rewarding with a good understanding. Whether you are preparing to be a nurse, physician, physician assistant, pharmacist, dentist, nurse practitioner, pharmacy technician, pharmacologist, or other healthcare professional, this podcast will help you better understand pharmacology. In addition to giving you the basics like mechanism of action, side effects, drug interactions, etc., you will also be exposed to how medications actually impact patients in real life. In the Real Life Pharmacology podcast, Eric Christianson, PharmD shares his real world experiences about how a medication's mechanism of action, pharmacokinetics, adverse effects, and drug interactions can actually impact patients in both a positive and a potentially negative way. Eric Christianson PharmD is the author of the popular clinical pharmacy blog Meded101.com. People who are passionate about nursing, medicine, or pharmacy will find this podcast beneficial in helping them prepare for passing exams. This podcast is for educational purposes only and is not medical advice or intended to be a substitute for medical advice. Please seek advice from your pharmacist or primary care provider if you have questions about medications that you are taking.