Antidotes for the Intoxicated Patient

SSRI, selective serotonin reuptake inhibitors; MAO, monoamino oxidase.

TABLE 14.2 Causes to Consider in Coma and Seizures Due to Toxins

Coma	Seizures
Alcohols	Tricyclic antidepressants
Carbon monoxide	Cocaine
Benzodiazepines	Amphetamines
Opiates	Theophylline
Antidepressants (especially tricyclics)	Antiepileptics (overdose)
Antipsychotics	Opiates (especially meperidine)
Antihistamines	Baclofen
Barbiturates	Beta-blockers
Other anticonvulsants	Clonidine
Other drugs of abuse	Hypoglycemic agents
Salicylates	Calcineurin inhibitors
Hypoglycemic agents	Other immunosuppressants (e.g., vincristine, cisplatin, intrathecal methotrexate)

Algorithms and lists are useful to keep around, but there are some caveats. Flumazenil lowers the seizures threshold and should not be used in patients with history of seizures or at high risk for having them. It is, therefore, unsafe to administer flumazenil in patients with suspected mixed overdoses which might include drugs that reduce seizure threshold. Naloxone and flumazenil are short-acting, so the improvement of the patients may be quite brief. Intubated patients should not be extubated while transiently more alert as many will lapse again into stupor and become once more unable to protect the airway. One should also be prepared to treat symptoms of acute opiate or benzodiazepine withdrawal when trying these medications. These agents are useful to prove the diagnosis and repeated doses can be used (continuous infusion of naloxone can be used as well), but they do not eliminate the toxin and therefore do not solve the problem. Supportive therapy is needed for severe opiate and benzodiazepine intoxications to resolve.

TABLE 14.3 Specific Treatment Considerations: Activated Charcoal, Hemodialysis or Hemoperfusion, and Specific Antidotes