Scopolamine

It is structurally similar to the neurotransmitter acetylcholine and acts by blocking the muscarinic acetylcholine receptors; it is thus classified as an anticholinergic[?].

In medicine, it it usually used in the form scopolamine hydrobromide. It can be used as a depressant of the central nervous system, though it can cause delirium in the presence of pain, mydriasis (pupillary dilation), and cycloplegia (paralysis of the eye muscles). When combined with morphine, it produces a tranquilized state known as twilight sleep[?] and amnesia. Although originally used in obstetrics it is now considered dangerous.

It is used in ophthalmy[?] to deliberately cause cycloplegia and mydriasis so that certain diagnostic procedures may be performed. It is also used in the treatment of iridocyclitis.

It is also an antiemetic (prevents vomiting), antivertigo[?] (prevents dizziness), and antispasmodic (prevents convulsions). It can be used as a pre-anesthetic sedation, as an antiarrhythmic (preventing irregular heartbeat) during anesthesia, and for the prevention of motion sickness.

The drug is highly toxic and has to be used in minute doses. An overdose can cause delirium, delusions, paralysis, stupor[?] and death.

The use of scopolamine as a truth drug was investigated by various intelligence agencies, including the CIA, during the 50s. It was found that, due to the hallucinogenic side effects of the drug, the truth was prone to distortion, and the project was subsequently abandoned.