Which one of the following is not considered an effective therapy for migraine headaches?

Moderate sodium restriction is not considered an effective therapy for migraine headaches. The management of migraines typically involves addressing triggers and utilizing specific medications or non-pharmacological approaches that have demonstrated efficacy in alleviating headache episodes.

Propranolol, a non-selective beta-blocker, is widely recognized as a preventive treatment for migraines. It has been used successfully to reduce the frequency and severity of headache attacks. Cold packs to the forehead can also provide symptomatic relief during a migraine attack by reducing inflammation and numbing the pain, making it a common non-pharmacological remedy.

Trimethobenzamide is primarily used as an antiemetic and may help control nausea associated with migraines, but it does not target the underlying headache itself, nor is it a primary preventive medication.

In contrast, moderate sodium restriction is not supported by current evidence as a specific or effective therapy for managing migraine attacks. While some dietary triggers can exacerbate migraines, sodium restriction does not regularly appear as a recognized treatment pathway in migraine management. Therefore, the choice of moderate sodium restriction as an answer highlights its lack of impact compared to established migraine treatment strategies.