Benztropine

3 - (10,11 - dihydro - 5H - dibenzo[a,d]cyclohepten- 5-yloxy)-tropane citrate inhibiting salivary secretion in the rabbit at an ED50 of 110 mg/kg s.c. and 28 mg/ kg p.o. (Funcke et al. 1964) was tested in rats inhaling micronized drug in combination with the P-adrenergic isoprenaline (Fig. 75). 

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H-1 -Benzoxocin, 3,4,5,6-tetrahydro-synthesis, 7, 668 Benzoxocinones synthesis, 7, 669 Benzoxocinones, dihydrosynthesis, 7, 669 Benzpyrinium bromide as pharmaceutical, 1, 158 Benzquinamide as pharmaceutical, 1, 147 Benzthiazide diuretic activity, 3, 1084 Benzthiazuron as herbicide, 1, 188 Benztropine... 

Common Name Tropine benzohydryl ether methanesulfonate, Benztropine methanesulfo-nate (See also Benzatropine Mesylate)... 

Diphenyl diazomethane Benztropine mesylate a/l -Diphenyl-7.dimethylamino valeronitrile Aminopentamide Diphenylmethane... 

Extrapyramidal effects usually diminish with a reduction in the dosage of the antipsychotic drug. The primary health care provider may also prescribe an antiparkinsonism drug, such as benztropine (see Chap. 29) to reduce the incidence of Parkinson-like symptoms. 

A patient taking chlorpromazine (Thorazine) for schizophrenia is also prescribed die antiparkinson drug benztropine What is the best explanation for adding an antiparkinson drug to die drug regimen ... 

Trihexyphenidyl (Artane) and benztropine (Cogentin) are prescription drugs used in the treatment both of Parkinson s disease and the extrapyramidal side effects produced by neuroleptic medication. They are occasionally abused for their mind-altering properties, which occur at toxic doses (Perry et al. 1978). Abusers often try to obtain these drugs by false representation of extrapyramidal symptoms, which are claimed to result from the use of phenothi-azines or other neuroleptics (Rubinstein 1978). 

In contrast to the nicotinic antagonists and indeed both nicotinic and muscarinic agonists, there are a number of muscarinic antagonists, like atropine, hyoscine (scopolamine) and benztropine, that readily cross the blood-brain barrier to produce central effects. Somewhat surprisingly, atropine is a central stimulant while hyoscine is sedative, as least in reasonable doses. This would be the expected effect of a drug that is blocking the excitatory effects of ACh on neurons but since the stimulant action of atropine can be reversed by an anticholinesterase it is still presumed to involve ACh in some way. Generally these compounds are effective in the control of motion but not other forms of sickness (especially hyoscine), tend to impair memory (Chapter 18) and reduce some of the symptoms of Parkinsonism (Chapter 15). 

Antimuscarinic drugs such as atropine have been used to modest effect in the treatment of PD for more than a century attenuating tremor and rigidity but with little effect on akinesia. Currently benzhexol and benztropine are sometimes added to levodopa therapy but peripheral effects such as dry mouth, blurred vision and constipation are unpleasant. They are also often used to counteract neuroleptic-induced extrapyramidal effects. 

Anticholinergics (various, including trihexyphenidyl, benztropine) Block Ach, decrease Ach DA ratio 80 mlZminute... 

Treatment includes IM or IV AChs (Table 71-4) or benzodiazepines. Benztropine mesylate, 2 mg, or diphenhydramine, 50 mg, may be given IM or IV, or diazepam, 5 to 10 mg slow IV push, or lorazepam, 1 to 2 mg IM, may be given. Relief usually occurs within 15 to 20 minutes of IM injection or within 5 minutes of IV administration. The dose should be repeated if no response is seen within 15 minutes of IV injection or 30 minutes of IM injection. 

AChs are an effective treatment (see Table 71-4). Benztropine has a half-life that allows once- to twice-daily dosing. Dose increases above 6 mg/day must be slow because of nonlinear pharmacokinetics. Trihexyphenidyl, diphenhydramine, and biperiden usually require three-times-daily dosing. Diphenhydramine produces more sedation, but all of the AChs have been abused for euphoriant effects. 

Anticholinergics are rarely used. One wonders why they are used at all, for in most cases, the experience is unpleasant or frightening. Still, stories are told of people who separate scopolamine and other anticholinergics from cold remedies, or people who use jimson weed, and of those who abuse prescription anticholinergics, such as amitryptyline, trihexyphenidyl, or benztropine mesylate. One can only assume that for some people, any alteration of consciousness, even though it may not be pleasant, is desirable. 

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