Dysfunction of CNS: Trigeminal & intercostal neuralgia, ischialgia, polyneuritis, diabetic neuropathy, myelitis, herpes zoster, pregnancy-associated neuritis, optical neuritis, peripheral facial neuritis, cervical syndrome & lumbago). Intoxication due to various etiology: Vomiting during pregnancy, post-op vomiting, iatrogenic cases (eg, due to intake of INH, reserpine, phenothiazine, alcoholism).