A patient ingested some unknown substance and presented with myoclonic jerks, seizures, tachycardia and hypotension. ECG shows a heart rate of 120/min. The arterial blood revealed a pH of 7.25, pCO2 of 30 mm Hg and bicarbonate ions are 15 mmol/L. The most likely  poisonous agent is:
Amanita phalloides
Ethylene glycol
Imipramine
Phencyclidine