For hiccups lasting 6 hours, first try simple physical maneuvers like holding your breath, drinking ice-cold water, or swallowing a teaspoon of sugar. If these home remedies do not work, prescription medications such as Chlorpromazine, Baclofen, or Metoclopramide can be prescribed by a doctor. I strongly advise against self-medicating. Please visit a physician or an urgent care clinic for a proper evaluation to identify any underlying causes and obtain the correct prescription. Seek immediate emergency care if you also experience chest pain, difficulty breathing, or swallowing issues.