Antivert
[Poisoning by diphenhydramine--forensic-toxicologic interpretation of analytic results ]

[Article in German]

Aderjan R, Bosche J, Schmidt G.

Several poisonings by diphenhydramine were reported shortly after it had been introduced as an antihistamine in 1945. In the Federal Republic of Germany its combination with 8-chlorotheophylline (dimenhydrinate) is available as a hypnotic without prescription. Replacing the dangerous diethylpentenamide diphenhydramine is a drug which is also often abused. Fatal poisonings, suicide attempts, and traffic accidents were increasingly observed. In seven cases drug-influenced road users caused traffic accidents. We observed blood concentrations of diphenhydramine as high as in four cases of clinically treated patients after ingestion of large doses. This indicates a serious drug abuse. The measurement of the concentration of diphenhydramine and its major metabolite (diphenmethoxy acetic acid) in blood and urine is a means of recognizing chronic use and misuse of diphenhydramine. As the metabolite accumulates in blood one may find an elevated level after multiple dosing. Shortly after taking a single dose no or only low metabolite concentration is found. The concentration of diphenhydramine and its metabolite was measured in several fatal cases. In one of these cases the concentration in body fluids and tissues was in a range not observed until now.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7124127&dopt=Abstract dimenhydrinate meclizine Antivert



Antivert
[Immediate effects of dimenhydrinate on uterine contraction and the fetal cardiac rhythm during labor]

[Article in French]

Lemay M, Samaan M, St Michel P, Granger L, Pigeon R.

The effects of intravenous administration of 100 mg of dimenhydrinate (Gravol) were studied in 20 patients during active spontaneous labour. The uterine activity and the fetal heart rate were monitored by an invasive technique. After administration of the medication the uterine activity increases significantly, and in 20% of the cases decelerations in the fetal heart rate of the hypoxic type occurred. Because of its unpredictable effects, this drug should be used with care during labour.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7127229&dopt=Abstract dimenhydrinate meclizine Antivert



Antivert
Diazepam as an anti-motion sickness drug.

McClure JA, Lycett P, Baskerville JC.

Diazepam has been used empirically for the relief of vertigo and, in addition, there are animal studies to suggest that this drug suppresses the vestibular system. One might anticipate therefore that diazepam would be an effective antimotion sickness drug. To study this, motion sickness was generated in four groups of normal subjects by having the subject make controlled head movements while rotating at constant velocity. Every subject was subjected (using a double-blind technique) to four different drug states, namely no drug, placebo, dimenhydrinate, and diazepam. Each group of subjects received the drug state at a different time interval (i.e. 30, 60, 90, and 120 min) prior to the motion sickness exposure. Motion sickness endpoints were measured subjectively using a nausea scale and objectively using a sweat sensor. The results showed significant antimotion sickness properties for both dimenhydrinate and diazepam as compared to the placebo. For the time intervals studied, the maximum effect was obtained at 120 min for both drugs.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7131636&dopt=Abstract dimenhydrinate meclizine Antivert



Antivert
A comparison of some effects of three antimotion sickness drugs on nystagmic responses to angular accelerations and to optokinetic stimuli.

Collins WE, Schroeder DJ, Elam GW.

While the basic efficacy of antimotion sickness drugs is rooted in the reduction of motion sickness symptoms, adverse side effects are important practical considerations of their usage in aviation. This study examined the influence of three established antimotion sickness drugs on nystagmic eye movement responses to angular acceleration (whole-body movement) with vision either permitted or denied, and to optokinetic stimulation (visual field movement). Dimenhydrinate and promethazine hydrochloride, particularly at higher dose levels, reduced optokinetic nystagmus, thereby making less accurate the following ability of the eye. During whole-body motion in darkness, there was little placebo-drug difference in the vestibular response under alert conditions; under relaxed conditions, dimenhydrinate and promethazine hydrochloride produced significant declines in the vestibular eye movements. These same drugs also interfered with the ability of the individual to fixate adequately on a visual task during motion. Subjects who received a combination of promethazine plus d-amphetamine were able to suppress vestibular eye movements and maintain good visual fixation under the task condition. Thus, the effect of a drug on nystagmus may be a poor indicator of its value in preventing motion sickness. Moreover, assessments of antimotion sickness drugs for many practical situations should include, as a possible adverse side effect, the inability to maintain visual fixation during motion.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7159338&dopt=Abstract dimenhydrinate meclizine Antivert