Edrophonium (or Tensilon) test
An edrophonium (or Tensilon) test may be performed to help confirm a diagnosis of myasthenia. This is usually performed on the Neurology day ward. It involves an injection of a medication called edrophonium (trade name Tensilon) which boosts the signal between nerve and muscle.
In most cases of myasthenia, edrophonium improves the muscle weakness but it's effect only lasts a few minutes. During the test you would be connected to a heart monitor as edrophonium tends to slow the heart rate. We usually use another medication, atropine, to minimise this side effect. Other rare side effects include fainting and breathing difficulties which is why the test is performed in a medically supervised setting.