Part 1 of Levine et al's excellent review on toxicology in the ICU. Some of their helpful recommendations/reminders:

• False positive UDS are common for tricyclics (diphenhydramine/Benadryl, carbamazepine, quetiapine/Seroquel), as are false negatives for benzodiazepines (lorazepam/Ativan, alprazolam/Xanax).

• The osmolal gap is elevated in ethanol, methanol, ethylene glycol, isopropanol, propylene glycol toxicity, but also in shock and ketonemia.

• Don't delay long giving glucose/dextrose while waiting for thiamine -- the Wernicke's encephalopathy worry is probably a bogeyman, more based on lore than evidence.

• Hemodialysis can remove salicylates/aspirin, methanol, ethylene & propylene glycol, valproate/Depakote, carbamazepine, lithium, phenobarbital, and theophylline, among others.

• Alkalinize the urine for salicylates/aspirin, methotrexate, phenobarbital, and other uncommon poisonings.

• Insulin can be used for calcium channel blocker toxicity with shock due to cardiac hypocontractility unresponsive to vasopressors.

Levine M et al. Toxicology in the ICU Part 1: General Overview and Approach to Treatment. CHEST 2011;140:795-806.