Achalasia medical therapy
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Medical Therapy
- Medication:
- Intra-sphincteric injection of botulinum toxin (or botox), to paralyze the lower esophageal sphincter and prevent spasms. As in the case of botox injected for cosmetic reasons, the effect is only temporary, and symptoms return quickly in most patients. Botox injections cause scarring in the sphincter which may increase the difficulty of later Heller myotomy. This therapy is only recommended for elderly patients who cannot risk surgery.
- BoTox acts as a zinc-dependant protease and cleaves a protein called SNAP-25. This results in a block of acetylcholine release from the presynaptic nerve terminal. As it is the excitatory neurons that release acetylcholine, a decrease in LES tone is observed.
- It has also been shown that BoTox interferes with cholinergic signaling in the myenteric nervous system that supplies smooth muscle, and hence also decreases smooth muscle contractility.
- Pasricha et.al. showed that 90% of patients experienced immediate relief, however only 65% have relief at 6 months, and only 42% are symptom free at one year.
- Relief was associated with a reduction in LES pressure by 40%, an increase in esophageal diameter by 17%, and a reduction in esophageal retention of 33%.
- BoTox is very well tolerated, and only ~ 5% develop symptomatic gastroesphageal reflux disease (GERD).
- The technique is currently being refined with even better results when injection is guided by endoscopic ultrasound.
- Some surgeons believe that BoTox can increase the difficulty of future surgery, and therefore recommend it only for patients who are not candidates for dilation or surgery.
- BoTox acts as a zinc-dependant protease and cleaves a protein called SNAP-25. This results in a block of acetylcholine release from the presynaptic nerve terminal. As it is the excitatory neurons that release acetylcholine, a decrease in LES tone is observed.
- Drugs that reduce LES pressure may be useful, especially as a way to buy time while waiting for surgical treatment. These include calcium channel blockers such as nifedipine, and nitrates such as isosorbide dinitrate and nitroglycerin. Unfortunately, many patients experience unpleasant side effects such as headache and swollen feet, and these drugs often stop helping after several months.
- Nitrates,
- Aminophylline,
- Terbutaline
- Ca++ channel blockers
- Decreases LES tone
- Usually only provide minimal relief.
- As the pills themselves can get stuck in the esophagus, this can complicate the disease.