The document discusses how different drugs can affect EEG interpretation. It notes that the quantity of medication in a patient influences the EEG, depending on factors like dose and metabolism. It provides examples of specific drugs that may elicit different EEG patterns, such as background slowing with phenytoin, excess beta with GABA agonists like barbiturates and benzodiazepines, epileptiform activity, triphasic waves, theta and delta activity, and coma patterns. Certain medications are also more likely to produce beta activity in children versus adults or with acute versus chronic use. Very high doses of some medications can cause spikes or polyspikes. Diffuse delta and excess theta may indicate neurotoxicity associated with certain anti-

1. Ade Wijaya, MD – January 2020

2.  Drugs can effect EEG interpretation
 Quantity of medication in the patient
influences the EEG. This quantity varies
according to dose, volume of distribution,
and rate of metabolism
 Systemic effects of medication, e.g.,
hyponatremia from Carbamazepine, may
diffusely perturb the EEG.
Blume WT. Drug effects on EEG. Journal of Clinical Neurophysiology. 2006 Aug 1;23(4):306-11.

3.  Background slower: Phenytoin and others
 Excess beta
 GABA agonists: barbiturates, benzodiazepines
 Epileptiform activity
 Triphasic waves
 Theta and Delta
 Coma patterns
Blume WT. Drug effects on EEG. Journal of Clinical Neurophysiology. 2006 Aug 1;23(4):306-11.

4.  Beta activity is more abundantly expressed by
medication in children than in adults and with
acute rather than chronic administration.
 Barbiturates and Benzodiazepines
 Cocaine, amphetamines, and
methylphenidate as well as tricyclic
antidepressants
 Withdrawal from alcohol and barbiturates
(G. Bauer and R. Bauer, 2005; Van Cott and Brenner, 2003)

8.  High doses of several types of medications may
elicit spikes or poly spikes that usually appear
bisynchronously in bursts, either spontaneously
or as a photoparoxysmal response
 Clozapine, Lithium, Phenothiazines, selective
serotonin reuptake inhibitors, and tricyclic
antidepressants.
 Acute withdrawal of alcohol or barbiturates may
also elicit bursts of spikes and polyspikes,
particularly as a photoparoxysmal response
(G. Bauer and R. Bauer, 2005; Van Cott and Brenner, 2003)

11.  Valproic Acid-associated hyperammonemic
encephalopathy
 Baclofen, Lithium, Levodopa, Pentobarbital,
and the serotonin syndrome
(Kifune et al., 2000)
(Chatrian and Turella, 2003; Dike 1997 Hormes et al., 1988; Kubicki and Stolzel, 1970; Lancman et al., 1997; Neufeld, 1992)

13.  Diffuse delta and excess theta may reflect
clinical neurotoxicity if associated with the
institution of one or more traditional AEDs
 Phenytoin
 Carbamazepine and valproate
 Clozapine, tricyclic antidepressants, and
lithium
(G. Bauer and R. Bauer, 2005; Van Cott and Brenner, 2003; Duncan 1987)

15.  Spindle coma
 Alpha/theta pattern
 Burst-suppression
 Electro-cerebral inactivity (ECI).
(G. Bauer and R. Bauer, 2005; Chatrian and Turella, 2003; Fisch, 1999; Ikeda et al., 2003; Young, 2002).