Esmolol; Indications/Uses, Dosage, Side effects, Drug Interaction ,Pregnancy Esmolol is a cardioselective beta1 receptor blocker with rapid onset, a very short duration of action, and no significant intrinsic sympathomimetic or membrane stabilizing activity at therapeutic dosages. Esmolol decreases the force and rate of heart contractions by blocking beta-adrenergic receptors of the sympathetic nervous system, which are found in the heart and other organs of the body. Esmolol prevents the action of two naturally occurring substances: epinephrine and norepinephrine. Esmolol is a cardioselective beta-blocker used in parenteral forms in the treatment of arrhythmias and severe hypertension. Esmolol has not been linked to instances of clinically apparent drug-induced liver injury. Mechanism of Action of Esmolol Similar to other beta-blockers, esmolol blocks the agonistic effect of the sympathetic neurotransmitters by competing for receptor binding sites. Because it predominantly blocks the beta-1 receptors in cardiac tissue, it is said to be cardioselective. In general, so-called cardioselective beta-blockers are relatively cardioselective; at lower doses they block beta-1 receptors only but begin to block beta-2 receptors as the dose increases. At therapeutic dosages, esmolol does not have intrinsic sympathomimetic activity (ISA) or membrane-stabilizing (quinidine-like) activity. Antiarrhythmic activity is due to blockade of adrenergic stimulation of cardiac pacemaker potentials. In the Vaughan Williams classification of antiarrhythmics, beta-blockers are considered to be class II agents. Indications of Esmolol High blood pressure Postoperative hypertension Nonvalvular atrial fibrillation Atrial fibrillation Atrial flutter Intra- or Post-op SVT or hypertension Supraventricular tachycardia Intraoperative hypertension Intraoperative tachycardia Noncompensatory sinus tachycardia Postoperative tachycardia Also for the rapid control of ventricular rate in patients with atrial fibrillation or atrial flutter in perioperative, postoperative, or other emergent circumstances where short term control of ventricular rate with a short-acting agent is desirable. Also used in noncompensatory sinus tachycardia where the rapid heart rate requires specific intervention. Contra-Indications of Esmolol Hypersensitivity to the active substance or to any of the excipients or other beta-blockers (cross-sensitivity between beta-blockers is possible) Sinus Bradycardia Suddenly serious symptoms of heart failure Emphysema Asthma attack Bronchospasm Kidney disease with a reduction in kidney function Blood circulation failure due to Serious Heart Condition Anaphylactic Shock due to Allergy Shots Severe sinus bradycardia (less than 50 beats per minute); Beta-Blockers (Beta-Adrenergic Blocking Agents) Decompensated heart failure; Sick sinus syndrome; severe AV-nodal conductance disorders (without pacemaker); 2nd or 3rd-degree AV-block; Cardiogenic shock; Concomitant or recent intravenous administration of verapamil. Non-treated phaeochromocytoma; Pulmonary hypertension; Acute asthmatic attack; Metabolic acidosis. Dosage of Esmolol Strengths: 10 mg/mL; 250 mg/mL; 20 mg/mL Atrial Fibrillation Recommended Dosing (Step 1) Optional loading dose (500 mcg/kg IV over 1 minute), then 50 mcg/kg/min IV for 4 minutes; if the response is adequate, the infusion may be maintained at 50 mcg/kg/min; if the response is inadequate, see step 2. (Step 2) Optional loading dose (500 mcg/kg IV over 1 minute) if necessary, then 100 mcg/kg/min IV for 4 minutes; if the response is adequate, the infusion may be maintained at 100 mcg/kg/min; if the response is inadequate, see step 3. (Step 3) Optional loading dose (500 mcg/kg IV over 1 minute) if necessary, then 150 mcg/kg/min IV for 4 minutes; if the response is adequate, the infusion may be maintained at 150 mcg/kg/min; if the response is inadequate, see step 4. (Step 4) If necessary, increase the dose to 200 mcg/kg/min IV Maintenance dose: 25 to 200 mcg/kg/min IV Maximum dose: 200 mcg/kg/min IV Duration: Maintenance infusions may be continued for up to 48 hours Atrial Flutter Recommended Dosing (Step 1) – Optional loading dose (500 mcg/kg IV over 1 minute), then 50 mcg/kg/min IV for 4 minutes; if the response is adequate, the infusion may be maintained at 50 mcg/kg/min; if the response is inadequate, see step 2. (Step 2) – Optional loading dose (500 mcg/kg IV over 1 minute) if necessary, then 100 mcg/kg/min IV for 4 minutes; if the response is adequate, the infusion may be maintained at 100 mcg/kg/min; if the response is inadequate, see step 3. (Step 3) – Optional loading dose (500 mcg/kg IV over 1 minute) if necessary, then 150 mcg/kg/min IV for 4 minutes; if the response is adequate, the infusion may be maintained at 150 mcg/kg/min; if the response is inadequate, see step 4. (Step 4) – If necessary, increase the dose to 200 mcg/kg/min IV Maintenance dose: 25 to 200 mcg/kg/min IV Maximum dose: 200 mcg/kg/min IV Duration: Maintenance infusions may be continued for up to 48 hours Intra- or Post-op SVT or Hypertension Immediate Control Administer 1 mg/kg IV as a bolus dose over 30 seconds followed by 150 mcg/kg/min if needed Adjust the infusion rate as required to maintain desired heart rate and blood pressure (refer to maximum recommended doses) Gradual Control Administer 500 mcg/kg IV as a bolus dose over 1 minute followed by a maintenance infusion of 50 mcg/kg/min IV for 4 minutes Infusion may be continued at 50 mcg/kg/min or, if the response is inadequate, titrated upward in 50 mcg/kg/min increments (increased no more frequently than every 4 minutes) to a maximum of 300 mcg/kg/min; may administer an optional loading dose equal to the initial bolus (500 mcg/kg over 1 minute) prior to each increase in infusion rate Maximum Recommended Doses For the treatment of tachycardia, maintenance infusion dosages greater than 200 mcg/kg/min IV are not recommended; dosages greater than 200 mcg/kg/min IV provide little additional heart-rate-lowering effect and the rate of adverse reactions increases. For the treatment of hypertension, higher maintenance infusion dosages (250 to 300 mcg/kg/min) may be required; the safety of doses above 300 mcg/kg/min has not been studied. Side Effects of Esmolol The most common Dizziness Blurred vision confusion faintness, or lightheadedness when getting up from a lying or sitting position suddenly Orthostatic hypotension Xerostomia (dry mouth) A headache Fatigue Skin reactions Hypotension Anxiety Constipation Sedation (dose-dependent) Nausea/vomiting Weight gain/loss Pain below the ear (from salivary gland) Erectile dysfunction More common Abdominal or stomach pain, discomfort, or tenderness chills or fever difficulty with moving a headache, severe and throbbing joint or back pain muscle aching or cramping muscle pains or stiffness chest pressure or squeezing pain in the chest discomfort in arms, shoulders, neck or upper back excessive sweating feeling of heaviness, pain, warmth and/or swelling in a leg or in the pelvis sudden tingling or coldness in an arm or leg sudden slow or difficult speech sudden drowsiness or need to sleep fast breathing sharp pain when taking a deep breath fast or slow heartbeat coughing up blood rust colored urine decreased amount of urine Rare Anxiety change in vision chest pain or tightness confusion a cough Agitation arm, back, or jaw pain blurred vision chest pain or discomfort convulsions extra heartbeats fainting hallucinations a headache irritability lightheadedness mood or mental changes muscle pain or cramps muscle spasm or jerking of all extremities nervousness Drug Interactions of Esmolol Esmolol may interact with the following drug, supplements, & may change the efficacy of the drug alpha-1 blockers (e.g., doxazosin, prazosin, tamsulosin) alpha-2 blockers (e.g., clonidine, dexmedetomidine, methyldopa) angiotensin-converting enzyme inhibitors (ACEIs; e.g., captopril, ramipril) angiotensin II receptor blockers (i.e., irbesartan, losartan, valsartan) anti-psychotics (e.g., clozapine, olanzapine, quetiapine, risperidone) atorvastatin azole antifungals (e.g., itraconazole, ketoconazole, posaconazole) barbiturates (e.g., phenobarbital) benzodiazepines (e.g., alprazolam, diazepam, lorazepam) beta-agonists (e.g., formoterol, salbutamol, salmeterol) other beta-blockers (e.g., propanolol, metoprolol) calcium channel blockers (e.g., amlodipine, diltiazem, nifedipine, verapamil) carbamazepine cyclosporine dexamethasone diuretics (water pills; e.g., furosemide, hydrochlorothiazide) duloxetine lapatinib levodopa lidocaine MAO inhibitors (e.g., phenelzine, moclobemide, selegiline) macrolide antibiotics (e.g., azithromycin, clarithromycin, erythromycin) nilotinib nonsteroidal anti-inflammatory drugs (NSAIDs; e.g., ibuprofen, naproxen) other beta-blockers (e.g., atenolol, metoprolol, propranolol) pentoxifylline phosphodiesterase-5-inhibitors (e.g., sildenafil, tadalafil) selective serotonin reuptake inhibitors (SSRI; e.g., fluoxetine, paroxetine, sertraline) sunitinib theophyllines (e.g., aminophylline, oxtriphylline, theophylline) Pregnancy Catagory of Esmolol FDA Pregnancy Category C Pregnancy There are a limited amount of data from the use of esmolol hydrochloride in pregnant women. Studies in animals have shown reproductive toxicity .Based on the pharmacological action, in the later period of pregnancy, side effects on the foetus and neonate (especially hypoglycaemia, hypotension and bradycardia) should be taken into account.If treatment with Esmolol is considered necessary, the uteroplacental blood flow and foetal growth should be monitored. The new-born infant must be closely monitored. Lactation Esmolol hydrochloride should not be used during breast-feeding.It is not known whether esmolol hydrochloride/metabolites are excreted in human milk. A risk to the new-borns/infants cannot be excluded. References DrugBank http://www.drugbank.ca/drugs/DB00187 http://www.drugbank.ca/drugs/DB00187#targets EPA DSStox https://comptox.epa.gov/dashboard/dsstoxdb/results?search=DTXSID4022995 https://www.drugs.com/cdi/esmolol.html Human Metabolome Database (HMDB) http://www.hmdb.ca/metabolites/HMDB0014333 ClinicalTrials.gov https://clinicaltrials.gov/ LiverTox https://livertox.nlm.nih.gov/Esmolol.htm MassBank of North America (MoNA) http://mona.fiehnlab.ucdavis.edu/spectra/browse?inchikey=AQNDDEOPVVGCPG-UHFFFAOYSA-N https://www.webmd.com/drugs/2/drug-11485/esmolol-intravenous/details/list-contraindications NIST http://www.nist.gov/srd/nist1a.cfm PubMed Health http://www.ncbi.nlm.nih.gov/pubmedhealth/PMHT0010167/