Which medication can cause triphasic waves and periodic discharges on an EEG?

The presence of triphasic waves and periodic discharges on an EEG is most commonly associated with metabolic disturbances and certain medications that affect the central nervous system. Lithium is particularly noted for its potential to cause these specific EEG changes, especially in the context of lithium toxicity or when there are underlying metabolic issues, like renal impairment.

Lithium affects neurotransmission and can lead to various neurological side effects. The triphasic waves seen on the EEG in patients taking lithium are indicative of a diffuse cerebral disturbance, potentially linked to the medication's effects on ion channels and excitatory neurotransmitters. Thus, the correlation between lithium administration and the appearance of triphasic waves and periodic discharges makes it a key medication to consider in this context.

Other medications listed, while they can affect EEG readings in different ways, are not as directly associated with this specific pattern of abnormality. For instance, carbamazepine and phenobarbital are more commonly linked to generalized slowing, while valproate tends to cause specific types of spikes or slowing rather than the distinct patterns created by lithium. Therefore, understanding lithium's unique impact on the EEG is critical in recognizing its role in producing these findings.