Calcium-Channel Blocker OD
                        ==========================

Effects:  Bradycardia, blocks, decreased myocardial contractility, peripheral
        vasodilitation.  Also:  hyperglycemia, N/V, decreased LOC; coma or
        seizures.  Onset is _very fast_.

Toxic dose:  verapamil:  3.2g.  nifedipine:  340 mg.  Diltiazem:  ??

Treatment:  Fluids.  Pacemaker (may need very high amperage).  No ipecac;
        decreased LOC comes on suddenly. Pressors (epi, Isuprel, dopamine).
        Calcium gluconate 10% (.25 - 0.5 cc/kg; 20-35cc for adult) will reverse
        hypotension; may need frequent repeat doses or constant infusion.
        Glucagon:  5-10 mg IV then 3-5 mg per hour.  NG insertion may cause
        increased vagal tone that may cause worse bradycardia.  In severe cases:
        cardiopulmonary bypass.

þ Diagnosis:
 - mVO2 (pulmonary artery oxygen saturation) as marker for toxicity: not
   useful, nor is it a marker for shock as is usually thought, at least in
   calcium channel blocker toxicity. [SAEM 2004]

þ Insulin and Physiology:
 - BIG doses of insulin: 1 mg/kg (10x usual dose)
 - Bolus glucose and glucose drip, monitor closely
 - decreased ability of heart to use fatty acids (the main normal
   substrate)
 - glucose levels go high, become acidotic like DKA
 - pyruvate dehydrogenase changed to inactive form, partly from inability to
   use glucose, causes lactic acidosis.
 - Insulin good for MI, sepsis, shock, post-CABG. Why? Great data.
 - Experimental shock and heart block from Verapamil OD in dogs:  Glucagon,
   saline, calcium, epi: some survival, but all with insulin survived, even
   those with small doses of insulin.
 - Insulin helps the heart to use glucose, which it can't use otherwise;
   insulin changes PDH into active form. Makes lactic acidosis resolve, helps
   cardiac contractility. Fewer side effects than calcium (e.g.,
   extravasation), epi (ischemic gut), and glucagon has tachyphylaxis.
 - one unit per kg up to max 100 units
 - most poison centers are familiar with this protocol.

 Methylene Blue: