Anticholinergics benztropine

Corticosteroids (prednisone) in higher doses Anticholinergics (benztropine, trihexyphenidyl) Thyroid hormones (levothyroxine)... 

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

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. 

Take a Second Medication as a Countermeasure. Sometimes despite problematic side effects, it may be necessary that a patient remain on a particular medication. This is a good time to address the risk-benefit approach to side effects. The best comparison is not the side effects associated with a particular medication compared to the lack of side effects without taking the pill it is the side effects of treatment versus the consequences of the untreated disease state. So what if a patient is on a medication that works for them when previous trials have proved unsuccessful, but there is the presence of one or more uncomfortable side effects This does not necessarily leave you powerless to deal with the side effects. One approach is to use a second medication to counteract the side effect of the first medication. One common example of this approach is using anticholinergic medications such as diphenhydramine (Benadryl) or benztropine (Cogentin) to counteract certain side... 

Two extrapyramidal conditions, acute dystonia and akathisia, occur early during treatment, while parkinsonism tends to evolve gradually over days to weeks. All three reactions occur most commonly with the high-potency antipsychotics (Table 34.1) and are related to high Dz-receptor occupancy. Acute dystonia, which occurs in about 5% of patients on antipsychotic therapy, consists of uncontrollable movements and distortions of the face, head, and neck. It can be treated with centrally acting an-timuscarinic agents, such as benztropine, while antipsychotic therapy is temporarily discontinued. When this reaction subsides, the anticholinergic can be withdrawn. 

Geriatric Considerations - Summary Benztropine and related anticholinergics present significant risk to older adults. These drugs possess potent anticholinergic effects and can cause cognitive impairment, delirium, dry mouth, blurred vision, and increased risk of falls. The use of this drug and related compounds should be limited and when used, patients should be closely monitored. 

Benztropine Anticholinergic agent 1-2 mg po bid Dystonia, parkinsonian syndrome... 

Dopamine reuptake can be inhibited specifically by benztropine (4.80), an anticholinergic drug, as well as by amphetamines. Several specific DA reuptake inhibitors have been discovered, such as tandamine (4.81), bupropion (4.82), and nomifensine (4.83), which are all potent antidepressants. Tandamine also inhibits NE uptake. 

Anticholinergic agents benztropine mesylate biperiden hydrochloride ethopropazine hydrochloride procyclidine hydrochloride trihexyphenidyl hydrochloride... 

Common pharmacodynamic interactions involve the additive anticholinergic or antidopaminergic effects of antipsychotics. Thus, concomitantly administered antiparkinsonian agents (e.g., benztropine) may increase the chances of toxicity (e.g., delirium) while dopamimetic agents (e.g., levodopa) may counteract the antipsychotic or neurotoxic effects of these agents. 

In general, concomitant drugs with potent anticholinergic (e.g., benztropine) or bone marrow effects (e.g., carbamazepine) should be avoided. Toxicity with BZDs has been reported, including symptoms such as excessive sedation, sialorrhea, ataxia, and, in some instances fainting, loss of consciousness, and respiratory arrest ( 521, 522 and 523). Other potentially significant interactions reported in the literature include ... 

Adolescent boys may be more vulnerable to acute dystonia than adults. Although these adverse effects can be treated with anticholinergic agents, dose reduction should also be considered. For acute dystonia, diphenhydramine (25 to 50 mg) may be given orally or intramuscularly, as can equivalent doses of benztropine (1 to 2 mg/day). Diphenhydramine has both sedative and anticholinergic properties, with the former being helpful in calming the patient whereas the latter reverses the reaction itself. 

Elevations of TCA levels may occur when combined with CYP2D6 inhibitors or from constitutional factors. About 7% of the Caucasian population in the USA has a CYP2D6 polymorphism that is associated with slow metabolism of TCAs and other 2D6 substrates. Combination of a known CYP2D6 inhibitor and a TCA in a patient who is a slow metabolizer may result in additive effects. Such an interaction has been implicated, though rarely, in cases of TCA toxicity. There may also be additive TCA effects such as anticholinergic or antihistamine effects when combined with other agents that share these properties such as benztropine or diphenhydramine. Similarly, antihypertensive drugs may exacerbate the orthostatic hypotension induced by TCAs. 

Seeds of Datura stramonium have anticholinergic effects, similar to those seen with trihexyphenidyl and benztropine (Ebadi and Pfeiffer, 2005). 

Physostigmine, given intravenously, counteracts both the peripheral and central side effects of atropine and other anticholinergic drugs such as thioridazine (neuroleptic), imipramine (antidepressant), and benztropine (antiparkinsonian medication). 

Tertiary-amine muscarinic receptor antagonists gain access to the central nervous system and are therefore the anticholinergic drugs used to treat parkinsonism and the extrapyramidal side effects of antipsychotic drugs. Specific agents used primarily for these conditions include benztropine mesylate (Cogentin) and trihexyphenidyl hydrochloride (Artane, others). 

Perhaps because of their anticholinergic effects (cf benztropine, Chapter 28 Pharmacologic Management of Parkinsonism Other Movement Disorders), some of the Hi antagonists have significant acute suppressant effects on the parkinsonism symptoms associated with certain antipsychotic drugs. 

Anticholinergics. Antagonists at muscarinic cholinoceptors such as benztropine and bi-periden (p. 110) can be used to suppress the sequelae of the relative predominance of cholinergic activity in the striatum (in particular, tremor). Atropine-like peripheral side effects and impairment of cognitive function limit the tolerable dosage. Complete disappearance of symptoms cannot be achieved. 

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