In the treatment of achalasia, which medication can act as a muscle relaxant?

• A. Nifedipine
• B. Metoclopramide
• C. Omeprazole
• D. Phenytoin

Answer: (A)

Relieving achalasia symptoms hinges on reducing the pressure of the lower esophageal sphincter to allow easier passage of food. Nifedipine, a calcium channel blocker, directly relaxes smooth muscle by blocking calcium entry into the muscle cells. This lowers the resting tone of the lower esophageal sphincter, making it easier for the bolus to pass into the stomach. That muscle-relaxing effect is why this medication fits the treatment goal for achalasia.

The other drugs don’t provide this specific effect. Metoclopramide is a prokinetic that enhances gastric emptying and can increase esophageal or gastric motility, but it does not relax the lower esophageal sphincter and can even raise its tone. Omeprazole reduces acid production, addressing reflux symptoms rather than esophageal entry resistance. Phenytoin is an anticonvulsant with no role in relaxing esophageal smooth muscle.