The pharmacology of butorphanol, a 3,14-dihydroxymorphinan narcotic antagonist analgesic.

Butorphanol, a new, totally synthetic morphinan, which is chemically related to naloxone, has been demonstrated to have both analgesic and narcotic antagonist properties. In rodent antiwrithing analgesic tests, butorphanol was 4 to 30 times more potent than morphine and dl-pentazocine, respectively. As an antagonist, butorphanol was about equivalent to nalorphine and 30 times more potent than dl-pentazocine. On the basis of the naloxone-induced mouse jumping test and the lack of substitution in withdrawn morphine-dependent mice, it is estimated that the potential for physical dependence of butorphanol will be less than that of dl-pentazocine but greater than that of nalorphine and dl-cyclazocine. Animal data also show that agonistic actions of butorphanol, such as respiratory depression and miosis, reach ceiling effects which are lower than those seen with morphine with an increase in dosage. Thus, butorphanol differed from morphine which exhibited agonist effects in a dose-related manner. Butorphanol showed weak to moderate central depressant properties at doses which were considerably higher (greater than 100 X) than those producing analgesia. Minimal cardiovascular and respiratory effects were seen with butorphanol in conscious dogs.

Antitussive properties of butorphanol.

Butorphanol (levo-N-cyclobutylmethyl-3, 14-dihydroxy morphinan), a potent analgetic agent of the narcotic antagonist type with a low abuse potential in laboratory animals, was evaluated for antitussive activity in unanesthetized guinea-pigs and dogs. Subcutaneously, it was over 100 times more active than codeine, dextromethorphan and dl-pentazocine and about 20 times more active than morphine in the guinea-pig, while in the dog it was 100, 10 and 4 times more active than codeine, dl-pentazocine and morphine, respectively. Orally, butorphanol was 15-20 times more active than either codeine or dextromethrophan in both species. Naloxone reversed the antitussive effects of butorphanol, codeine, morphine and dl-pentazocine while those of dextromethorphan were not antagonized. The antitussive effect of butorphanol and morphine lasted about 4 hr and both compounds were longer acting than codeine. Butorphanol was also shown to be as effective against cough of pathological origin as against experimentally induced cough in the dog.

Pharmacology of a potent, new antithrombotic agent, 6-methyl-1,2,3,5-tetrahydroimidazo[2, 1-b] quinazolin-2-one hydrochloride monohydrate.

The effect of 6-methyl-1,2,3,5-tetrahydroimidazo[2,1-b] quinazolin-2-one hydrochloride monohydrate (BL-3459) on platelet function and experimental thrombosis was evaluated in a series of in vitro, ex vivo and in vivo animal experiments. Potent inhibition of platelet aggregation for BL-3459 was demonstrated by both in vitro and ex vivo techniques. In vitro, EC50 levels were less than 1 mug/ml regardless of the aggregating substance used or the species of animal from which platelet-rich plasma was obtained. After oral administration to rats and dogs, BL-3459 was rapidly absorbed and had a long duration of action. Ex vivo ED50 values were in the range of 2 to 3 mg/kg p.o. In addition, BL-3459 (1-10 mg/kg) demonstrated significant oral activity in a variety of in vivo animal models. BL-3459 inhibited elevation in screen filtration pressure induced by hemorrhage in dogs, endotoxemic death in rats, intravascular thrombosis produced by electrical stimulation of the carotid artery of the dog and thrombosis induced by means of a biolaser in the microvasculature of the rabbit ear chamber. In contrast to acetylsalicylic acid, BL-3459 had little effect on bleeding time in guinea pigs. Oral or intraduodenal administration of BL-3459 to dogs lowered aortic blood pressure, stroke volume and peripheral vascular resistance, while elevating cardiac rate and cardiac contractile force. Thus, it had little effect on the estimated cardiac output. These cardiovascular effects were mediated, in large part, through direct-acting mechanisms. BL-3459 exhibited weak antiserotonin activity in isolated smooth muscle preparations. While the precise mechanism of action of BL-3459 has not yet been determined, indications are that the compound may prove useful in the prevention of intravascular thrombosis.

Comparative effects of kanamycin and amikacin on aortic blood pressure, cardiac rate and surface electrocardiogram in the conscious dog.

Intravenous infusion in conscious beagle dogs of either kanamycin or amikacin to doses of 30 mg/kg resulted in little or no detectible dose related effects on mean aortic blood pressure, cardiac rate, the surface electrocardiogram or gross behavior. Increasing doses of kanamycin and amikacin resulted in dose-related increases in the plasma levels of the two antibiotics. These results indicate that in the conscious dog high plasma levels of kanamycin (64 mug/ml) and amikacin (78 mug/ml) were not associated with depression of systemic blood pressure.

A new method for the evaluation of analgesic activity using adjuvant-induced arthritis in the rat.

A bioassay was developed for the assessment of analgesic activity by using pain resulting from a reproducible pathological condition. The vocalization displayed by rats with adjuvant-induced polyarthritis was defined as an expression of pain, and a decrease of this response was established as specifically demonstrating analgesic activity. This method was capable of detecting the analgesic activity of morphine-like and narcotic antagonist-type analgesics, as well as the activity of the antipyretic analgesics. The relative potencies of known analgesic agents determined with this technique closely approximated the potencies of these analgesics in man. The instrumentation for recording and measuring the vocal response of arthritic rats is described.

Potential antifertility agents. 3. Substituted dibenzothiophenecarboxylic acids and derivatives.

PIP: The syntheses of 37 derivatives of 4-methyldibenzothiophene-3carboxylic acid were reported. Compounds were assayed for their estrogenic and antifertility activities in female mice and rats. In general cis isomers were more active than the trans. In certain postcoital dosing regimens, 2 analogs were more active in preventing or terminating pregnancy in rats than would have been predicted on the basis of their estrogenicity. The effectiveness of these 2 compounds in preventing pregnancy was 100 percent when administered on days 1-5 postcoitum in 1 mg. /kg. / day doses to rats. Effectiveness was the same whether administered orally or slbcutaneously.^ieng