There's no single "strongest" medicine for itching, as the best treatment depends on the underlying cause. Traditionally, antihistamines are used to treat itching caused by allergies. Examples include diphenhydramine (Benadryl), hydroxyzine (Atarax), and chlorpheniramine (Chlor-Trimeton and others).
For long-term itch, antidepressants called selective serotonin reuptake inhibitors (SSRIs) may help. Other medications include hydrocortisone, which reduces swelling and inflammation, and capsaicin, which can desensitize nerves.
For itching caused by cancer treatment, cholestyramine can reduce jaundice, which can cause itching. If you're unsure about the cause of your itching, it's best to consult a doctor for diagnosis and treatment recommendations.
