B Block Tox

by Marianne Sacasa, MD

Beta-Adrenergic antagonists are used to treat hypertension, ischemic heart disease, heart failure, arrhythmias, migraine headache, tremor, portal hypertension, aortic dissection… the list goes on to da break of dawn.

  • Physiology: Competitive antagonism of beta receptor →  decrease cAMP → decrease calcium → decrease contractility
  • Beta 1 Selective → depressed myocardial contractility, decreased automaticity in pacemaker cells, decreased conduction velocity.
  • Nonselective B Blocker→  bronchoconstriction, impaired gluconeogenesis, and decreased insulin release
  • Other properties: Lipophilicity and Membrane stabilizing activity (MSA)

 

Hypotensive and Bradycardic?

1.) ABCs – no surprise here.

2. IV Glucagoninitial bolus 5mg IVP over 1 min, can be repeated in 10-15 minutes. If changes noted in HR – start drip at 2mg-5mg/hour. Give antiemetics before administration of glucagon.

3. IV Calcium

Ca Chloride – Central line – 1g of 10% — to be repeated up to 3g

Ca Gluconate — Peripheral line – 30mL of 10% to be repeated up to 3g

Monitor Ca levels  q 4-6 hours; lethal iatrogenic overdose have been reported.

4. Vasopressor: Epinephrine 1mg/min

5. High dose Insulin/Glucose – remember back to med school – insulin’s physiology involves intracellular calcium utilization; we’ll spare you today though:

1 unit/Kg bolus following by 1 to 10 Unit/kg/hour

A hemodynamic response is delayed for 30 to 60 minutes

Monitor glucose and potassium (we do use insulin in hyperkalemia therapy after all) every 30 to 60 minutes

6. Lipid Emulsion Therapy – check out the physiology mentioned above. BBs love lipids; this  therapy tries to coax them out of the body’s tissue and into the emulsion

7. Activated Charcoal: 1g/kg by mouth or NGT one to two hours after ingestion

8. Hemodialyis: effective only with overdose of hydrophilic minimal protein bound beta blockers – we’re looking at you, Atenolol.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s