Narcotic potentiating activities

Tranquillizing drugs based on the phenothiazine nucleus potentiate the action of narcotic analgesics [157] although there are some reports to the contrary [158] and certain derivatives, notably methotrimeprazine (levomepromazine, Levo-prome, Veractil) (—)-(LV), are claimed to have intrinsic analgesic activity. In mice, (-)-(LV) is more potent than morphine in a variety of tests [159, 160] for example hot-plate EDso value of 1.02 mg/kg, that of morphine 2.1 mg/kg. 

Drugs in this least restrictive category have an accepted medical use and relatively low potential for abuse and dependence compared to the drugs in Schedule 4. Most Schedule 5 drugs are compounds or mixtures that contain narcotics mixed with other active ingredients that also have a medical effect. 

In compounds with stronger p-agonistic activity (buprenorphine and pentazocine), the abuse potential is marked and in contrast to earlier estimations, both compounds had to be subjected to narcotic control. In compounds with a marked K-agonistic component (cyclazocine, nalorphine) the dysphoric side effects are so prominent that the compounds could not be used for therapeutic purposes. 

Even the simplest 1-organylsilatranes potentiate the narcotic activity of hexa-barbital33. They possess an analgetic and sedative effect. 1-Methylsilatrane is most active in this respect. 

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