Scopolamine preanesthetic

Preanesthetic medications such as morphine, scopolamine, benzodiazepine, and buty-rophenones lower dysphoric effects of ketamine. Synonyms for this drug are ketanest, ketalar, and others. 

Sradycard/a Atropine is used in the suppression of vagally mediated bradycardias. Preoperative medication Atropine, scopolamine, hyoscyamine, and glycopyrrolate are used as preanesthetic medication to control bronchial, nasal, pharyngeal, and salivary secretions and to block cardiac vagal inhibitory reflexes during induction of anesthesia and intubation. Scopolamine is used for preanesthetic sedation and for obstetric amnesia. 

The use of atropine became part of routine preoperative medication when anesthetics such as ether were used, because these irritant anesthetics markedly increased airway secretions and were associated with frequent episodes of laryngospasm. Preanesthetic injection of atropine or scopolamine could prevent these hazardous effects. Scopolamine also produces significant amnesia for the events associated with surgery and obstetric delivery, a side effect that was considered desirable. On the other hand, urinary retention and intestinal hypomotility following surgery were often exacerbated by antimuscarinic drugs. Newer inhalational anesthetics are far less irritating to the airways. 

Scopolamine (0.32 to 0.65 mg SC, IM, or IV) is indicated for producing preanesthetic sedation and obstetric amnesia in conjunction with analgesics. It may be used for calming delirium and for motion sickness. 

Atropine and scopolamine differ quantitatively in their ability to affect the CNS. Whereas atropine has almost no detectable effect on the CNS in doses that are used clinically, scopolamine has prominent central effects already at low doses. This difference may be due to the greater permeation of scopolamine through the blood-brain barrier. Clinical doses of atropine cause mild excitation. At steadily increasing doses, central excitation is increased, but then central depression follows, leading to circulatory collapse, respiratory failure and coma. This, however, is only of toxicological interest. Therapeutic doses of scopolamine cause a CNS depression manifested by drowsiness, amnesia, fatigue. These effects are utilized to prevent motion sickness and as an adjunct for preanesthetic medication. Tropane alkaloids have also long been used in Parkinsonism, especially before the discovery of levodopa. 

Scopolamine is found in the leaves of Datura metel L., D. meteloides L., and D. fastuosa var. alba (Cordell 1978). It is used as a sedative, a preanesthetic agent, and in the treatment of motion sickness (Merck 1989). 

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