Antivert
[Effect of pharmacological agents and coagulation of the n. raphe dorsalis on morphine effects]

[Article in Bulgarian]

Bantutova I.

The authors carried out studies on 96 female rats of Wistar strain and examined the influence of various pharmacological means and the coagulation of n. raphe dorsalis on cataleptic state, hyperthermia, and analgethic effect, induced by single administration of morphine. She found that LSD and preliminary treatment with parachlorphenylalanine caused enhancement of hyperthermic reaction to morphine. Acetyl-salicyliaccid had no effect on the hyperthermic reaction: dimenthydrinate and propranolol did alter it significantly, but cyproheptadine inhibited it. In respect to the cataleptic state, induced by morphine, she found that pharmacological means with various mechanism of action (parachlorphenylalatine, dimenhydrinate, cyproheptadine, propranolol and LSD) inhibited this states, but haloperidol enhanced it. She suggests that the hyperthermic reaction of morphine is due to, its action on serotoninergic neurones, regulating thermoregulation. She makes a guess that cataleptic state, induced by morphine, depends on the change in mediator interrelations (acethycholine, serotonine, dopamine). The lack of changes on the analhethic affect of morphine after coagulation of n. Raphe dorsalis, from which a part of accending serotoninergic pathways, supports the existing data in literature that both descending and accending serotoninergic pathways are of significance for analgethic action of morphine.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=160312&dopt=Abstract dimenhydrinate meclizine Antivert



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Inhibition of human and rabbit liver steroid and xenobiotic UDP-glucuronosyltransferases by tertiary amine drugs--implications for adverse drug reactions.

Sharp S, Mak LY, Smith DJ, Coughtrie MW.

Department of Biochemical Medicine, University of Dundee, Ninewells Hospical and Medical School, Scotland, UK.

1. To investigate the hypothesis that disruption of glucuronidation of endogenous compounds by drugs represents a potential mechanism for pathogenesis of adverse drug reactions, the effects of a range of tertiary amine and amide drugs (many with effects on sex hormone function) on steroid hormone and xenobiotic UDP-glucuronosyltransferase activities in human and rabbit liver microsomes were studied in vitro. 2. Chlorpromazine, amitriptyline, imipramine, promethazine and cyproheptadine were consistently the most potent inhibitors of the glucuronidation of testosterone, androsterone, oestriol and 1-naphthol, the steroid activities being more susceptible to inhibition (up to 90%). 3. Carbamazepine, diphenhydramine, sulphadimethoxine, dimenhydrinate and (+/-)-chlorpheniramine had little effect on the UDPGT activities measured. 4. The structural features within this group of compounds required for inhibitory potency were the presence of a rigid tricyclic ring (e.g. phenothiazine) and either a dimethylaminopropyl or a methylpiperidine side-chain. 5. The implications of these data for involvement of disruption of the normal cellular function of glucuronidation in the pathogenesis of frequently observed adverse side-effects associated with these compounds are discussed.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1615704&dopt=Abstract dimenhydrinate meclizine Antivert



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Colic medication and apparent life-threatening events.

Hardoin RA, Henslee JA, Christenson CP, Christenson PJ, White M.

Southwest SIDS Research Institute, Lake Jackson, Texas 77566.

Eight infants with histories of apnea and cyanosis were referred to the Southwest SIDS Research Institute for evaluation of apparent life threatening events (ALTE). All of the infants had been treated for colic with a 1:1 concentration of dimenhydrinate (Dramamine) and phenobarbital, hyoscyamine sulfate, atropine sulfate and scopolamine hydrobromide (Donnatal). The medication was pre-mixed by local pharmacists. A comprehensive work-up failed to reveal a cause for the ALTE in any infant. The Dramamine/Donnatal mixture was withdrawn and polygraphic evaluation was conducted. Cardiorespiratory abnormalities were identified in all eight infants and significant gastroesophageal reflux (GER) was documented in four. The possibility that colic medication contributes to cardiorespiratory instability and GER in vulnerable infants requires serious consideration and further evaluation.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2044336&dopt=Abstract dimenhydrinate meclizine Antivert



Antivert
[The effect of a dimenhydrinate combination of the cardiovascular system and cerebral blood circulation in the anaesthetized dog]

[Article in German]

Hahn N, Felix R, Sonnenfeld A, Babour A, Heidari S.

The influence of Vertigo-Vomex (VV) and Vertigo-Vomex Retard (VVR) on the perfusion rate of the a. carotis interna and on the peripheral circulation was tested in 30 anaesthetized dogs. These drugs represent beta-dimethylamino-ethyl-benzhydrylether-1,3-dimethyl-8-chloroxanthine (dimenhydrinate, Vomex A) with the addition of pyridine-3-carbonic acid (nicotinic acid, niacin) and pyridoxine-HCl (vitamin B6) and its retard preparation. A) Angiographic researches of the brain vessels after i.v. injection of VV. B) Perfusion rate in the a. carotis int. by electromagnetic flowmeter; measurements of blood pressure, heart rate, and acid-base balance; reactions after injection of niacin, dimenhydrinate, and pyridoxine-HCl as well as after a combination of both. C) Same measurements as in B but after oral application. In one out of four cases there was a dilation of the brain vessels, in two cases there was a small one, in one case there was none. Niacin induces a short-lasting augmentation of the perfusion rate in the a. carotis int. simultaneously with rising aortic blood pressure. Dimenhydrinate with pyridoxine-HCl slightly increases the heart rate. Combined with niacin the perfusion rate shortly increases immediately after injection of niacin without any rise of blood pressure but combined with a fall in blood pH and standard bicarbonate. After oral application of VVR there was a slight but not significant augmentation of the perfusion rate in the a. carotis int. combined with rising blood pressure but with no change of the blood pH. Therefore the certain intivertigineous effect of VV and VVR cannot be explained by a rise of the perfusion rate in the inner ear or in the brain. In view of our results the central effect of dimenhydrinate combined with niacin and pyridoxine-HCl hypothetically may be improved by metabolic influences on the cells and their membranes.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=235268&dopt=Abstract dimenhydrinate meclizine Antivert



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Discriminable effects of antihistamine drugs.

Overton DA.

Rats were trained to discriminate drug vs. no-drug in a shock-escape T-maze task; a right turn was required when rats were drugged and a left turn when undrugged. The three antihistamine drugs pyrilamine, dimenhydrinate (Dramamine) and diphenhydramine (Benadryl) were discriminated after an average of 20 training sessions indicating that their effects were only moderately discriminable. After criterion performance was achieved under the training conditions, substitution tests were conducted during which rats received a novel drug and were then run in the maze with both goals accessible. Rats trained with antihistamine drugs made drug choices during tests with other antihistamines. Rats trained with other types of drugs made no-drug choices during tests with antihistamines. The results suggest that the antihistamines share a discriminable effect which is relatively unique to that class of drugs.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=28095&dopt=Abstract dimenhydrinate meclizine Antivert