Other drugs that can cause hypokalemia include Amphotericin B Antipseudomonal penicillins (eg, carbenicillin) Penicillin in high doses Theophylline (both acute and chronic intoxication) Symptoms and Signs of Hypokalemia Mild hypokalemia (serum potassium 3 to 3.5 mEq / L [3 to 3.5 mmol / L]) rarely causes symptoms.