Tensilon

Tensilon is the brand name for edrophonium chloride, a short-acting acetylcholinesterase inhibitor used in neurology to aid the diagnosis of myasthenia gravis (MG) and to differentiate MG from other causes of weakness. It is most commonly associated with the Tensilon test, a diagnostic procedure performed in clinical settings to assess neuromuscular transmission.

Edrophonium works by reversibly inhibiting acetylcholinesterase, the enzyme that breaks down acetylcholine at the neuromuscular junction. By increasing acetylcholine availability, it temporarily improves muscle strength in individuals with MG, who have reduced transmission at the postsynaptic receptors. The drug’s effects are rapid, typically beginning within seconds to a minute and lasting only a few minutes.

In practice, Tensilon testing involves administering edrophonium under careful medical supervision, with continuous monitoring of muscle strength and vital signs. A transient improvement in weakness supports a diagnosis of MG, whereas little or no improvement, or a worsening pattern, prompts consideration of alternative diagnoses or a cholinergic crisis. Because edrophonium can cause bradycardia, arrhythmias, bronchospasm, or excessive secretions, the procedure requires appropriate monitoring and preparedness for adverse reactions.

Safety concerns have led to reduced use of the Tensilon test in some settings, with reliance on other diagnostic approaches for MG in many places. Edrophonium is available in injectable form and is used in hospital settings under controlled conditions.