Drug induced bradycardia

drug induced bradycardia case study, drugs causing decrease in heart rate.

1. Drug induced B radycardia Name: Dr Anjum Ahamadi Pharm. D

2. Definition Bradycardia or bradyarrhythmia is the heart rate, i.e. ventricular rate less than 60 bpm in the setting of sinus rhythm, a variety of atrial rhythms, atrial fibrillation/flutter, junctional , or idioventricular rhythm and advanced atrioventricular (AV) block. Drug-induced bradycardia in adults is frequently observed.[1]

3. Types of Bradycardia Drug-induced bradycardia : In the heart with normal sinus and AV node and normal infranodal conduction, drug-induced bradycardia may be due to overdosage and toxic effect of medication, or to a synergistic ‘ brady effect’ of several medications. Drug-provoked bradycardia : In the heart with underlying latent disease of the sinus and/or AV node, and/or infranodal conduction system, bradycardia may be due to a trigger effect of even sub-therapeutic doses of drugs inducing bradycardia . This kind of ‘drug-induced’ bradycardia should be classified as drug-provoked bradycardia . It is important to note that generally drugs inducing bradycardia (β- and calcium channel blockers and most anti-arrhythmic drugs) have no influence on infranodal conduction.

4. Drug-associated bradycardia : In patients with underlying latent disease of the sinus and/or AV node, and/or infranodal conduction, significant bradycardia may be associated with drugs inducing bradycardia but not due to a brady effect of these drugs. In patients with normal heart therapeutic doses of drugs inducing bradycardia generally cannot cause clinically significant bradycardia , especially due to AV block. This suggestion is logical extension of previous three. All definitions based on level of evidence C.[2]

5. Drugs causing B radycardia Clinically significant bradycardia can be induced by β-blockers, non- dihydropyridine calcium channel antagonists, digitalis, and anti-arrhythmic drugs. Other drugs include sympatholytic anti- hypertensives , tedisamil , carbamazepine, cimetidine, anti-depressants, lithium, opioid blockers, and cocaine. Severe symptomatic bradycardia has been observed after the eating of honey (called mad honey) produced from the nectar of rhododendrons (of the family Ericaceae ). Grayanotoxins extracted from this honey and injected to rats cause severe bradycardia .[8] There are case reports regarding a toxic effect of doxorubicin and antismoking remedy (herbs) leading to symptomatic bradycardia due to heart block. Bradyarrhythmia develops more commonly with amiodarone , sotalol and other β- blockers, propafenone , or flecainide than with procainamide, quinidine, or disopyramide ; combined drug therapy increases the risk of significant bradycardia .[1-7]

6. Case study

7. Subjective evidence Chief complains: A 74 years old female came with complains of low heart rate while monitoring at home. History of present illness: W as admitted for arterial flutter 6 days ago and was discharged within 4 days. Past medical history: HTN, DM, Hypothyroidism, Arterial flutter. Surgical history: PTCA to CAD 10 years ago.

8. Drug Dose Frequency T. Clopilet 75mg OD T. Aztor 40mg OD[HS] T. Eliquis 5mg BD T. Lasilactone 20/50mg OD T. Cordarone 200mg TID T. Pan 40mg OD T. Alprax 0.5mg OD T. Oxra 10mg OD T. Dilzem 30mg TID T. Thyronorm 100mcg OD Medical history :

9. Objective evidence Vitals: BP – 130/80, HR – 46, PR – 18, pallor. Lab values: Urea – 80mg/dl, serum creatinine – 1.55mg/dl, GRBS – 214mg/dl. ECG findings: P wave.

10. Assessment Drug induced Bradycardia . Significant Bradycardia .

11. Plan Hold Dilzem and Cardarone . IV NS 70ml/hr. Atropine 0.6mg should be administered as it is helpful in treating symptomatic sinus bradycardia . Stop IV fluids at night. Don’t provide fruits, juices, soups, coconut water. The patient was stable and asymptomatic after one day so, amiodarone 100mg od and dilzem regular dose was started and patient was shifted to room. Concomitant administration of amidarone and dilzem should be avoided.

12. Drug chart : Si. No. Drug Dose Frequency Indication 1. T. Clopilet 75mg OD CAD 2. T. Aztor 40mg HS CAD 3. T. Eliquis 5mg BD CAD 4 T. Lasilactone 20/80mg OD HTN 5. T. Dilzem 30mg TID Arterial flutter 6. T. Thyronorm 100mcg OD Hypothyroidism 7. T. Pan 40mg OD Gastric disturbance 8. T. Oxra 10mg OD DM 9. T. Amiodarone 100mg OD Arterial flutter 10. Inj. Insuline SC 6U [12U of GRBS - >336] SOS DM

13. Referance 1. Ovsyshcher IE, Barold SS (2004) Drug-induced bradycardia : to pace or not to pace? Pacing Clin Electrophysiol 27:1144–1147 2. I.E. OVSYSHCHER Drug-Induced, Drug-Provoked and Drug-Associated Bradycardia . 3. Friedman PL, Stevenson WG (1998) Proarrhythmia . Am J Cardiol 82:50N-58N 5. 4. Zipes DP (1987) Proarrhythmic effect of antiarrhythmic drugs. Am J Cardiol 59:26E-31E 5 . Hofman R, Leisch F (1995) Symptomatic bradycardia with amiodarone in patients with pre-existing conduction disorders. Wien Klin Wochenschr 107:640–644 7. 6. Israel CW, Ehrlich JR, Barold SS et al (2002) Treatment of tachyarrhythmias with pacing and antiarrhythmic drugs. In: Israel CW, Barold SS ( eds ) Advances in the treatment of atrial tachyarrhythmias : pacing, cardioversion , and defibrillation. Futura , Armonk, NY, pp 305–323 8. 7. Yusuf S, Camm AJ (2003) Sinus tachyarrhythmias and the specific bradycardia agents: a marriage made in heaven? J Cardiovasc Pharmacol Ther 8:89–105 8. Onat F, Yegen BC, Lawrence R et al (1991) Site of action of grayanotoxins in mad honey in rats. J Appl Toxicol 11(3):199–201