Anticholinergic property

Medications with anticholinergic properties induce mydriasis, which can lead to angle closure in pupillary block and plateau iris. Pupillary block may also be induced by drugs that cause miosis.12... 

Symptom relief is caused in part by anticholinergic properties, which are responsible for the drying effect that reduces nasal, salivary, and lacrimal gland hypersecretion. Antihistamines antagonize increased capillary permeability, wheal-and-flare formation, and itching. 

Lechevallier-Michel N, Molimard M, Dartigues JF et al. (2005) Drags with anticholinergic properties and cognitive performance in the elderly results from the PAQUID Study. Br J Clin Pharmacol 59(2) 143-151... 

Acetylcholine has been implicated in learning and memory in all mammals, and the gross deficits in memory found in patients suffering from Alzheimer s disease have been ascribed to a defect in central cholinergic transmission. This transmitter has also been implicated in the altered mood states found in mania and depression, while many different classes of psychotropic drugs are known to have potent anticholinergic properties which undoubtedly have adverse consequences for brain function. 

Synthesis of scopolamine (Fig. 4), a tropane alkaloid of known anticholinergic properties, was induced hy fivefold in hairy root cultures of Atropa belladonna overexpressing hyoscianine 6[3-hydroxilase. ... 

Drags that exhibit central anticholinergic properties are used in treating Parkinsonism. It is believed that they do not affect the synthesis, release, or hydrolysis of acetylcholine. Their medicinal efficacy is manifest by the rednction or removal of motor disturbances cansed by damage to the extrapyramidal system. They reduce rigidity, and to a somewhat lesser degree, akinesia, and they have little effect on tremors. 

Anticholinergic properties Maprotiline should be administered with caution in patients with increased intraocular pressure, history of urinary retention, or history of narrow-angle glaucoma because of the drug s anticholinergic properties. 

Anticholinergic properties are highest in the aliphatic and piperidine groups, and lowest in the piperazine group. 

Both the direct and indirect actions of quinidine are important in determining its ultimate effect on A-V conduction. The indirect (anticholinergic) properties of quinidine prevent both vagally mediated prolongation of the A-V node refractory period and depression of conduction velocity these effects lead to enhancement of A-V transmission. Quinidine s direct electrophysiological actions on the A-V node are to decrease conduction velocity and increase the ERP. 

Quinidine also prolongs repolarization in Purkinje fibers and ventricular muscle, increasing the duration of the action potential. As in atrial muscle, quinidine administration results in postrepolarization refractoriness, that is, an extension of refractoriness beyond the recovery of the resting membrane potential. The indirect (anticholinergic) properties of quinidine are not a factor in its actions on ventricular muscle and the His-Purkinje system. 

The inherent anticholinergic properties of procainamide may interfere with the therapeutic effect of cholinergic agents. Patients receiving cimetidine and procainamide may exhibit signs of procainamide toxicity, as cimetidine inhibits the metabolism of procainamide. Simultaneous... 

The direct depressant actions of disopyramide on the sinoatrial node are antagonized by its anticholinergic properties, so that at therapeutic plasma concentrations, either no change or a slight increase in sinus heart rate is observed. Both the anticholinergic and direct depressant actions of disopyramide on sinus automaticity appear to be greater than those of quinidine. 

The major toxic reactions to disopyramide administration include hypotension, congestive heart failure, and conduction disturbances. These effects are the result of disopyramide s ability to depress myocardial contractility and myocardial conduction. Although disopyramide initially may produce ventricular tachyarrhythmias or ventricular fibrillation in some patients, the incidence of disopyramide-induced syncope in long-term therapy is not known. Most other toxic reactions (e.g., dry mouth, blurred vision, constipation) can be attributed to the anticholinergic properties of the drug. 

Because of its anticholinergic properties, disopyramide should not be used in patients with glaucoma. Urinary retention and benign prostatic hypertrophy are also relative contraindications to disopyramide therapy. Patients with myasthenia gravis may have a myasthenic crisis after disopyramide administration as a result of the drug s local anesthetic action at the neuromuscular junction. The elderly patient may exhibit increased sensitivity to the anticholinergic actions of disopyramide. 

Lidocaine minimally affects both the conduction velocity and the ERP of the A-V node. Lidocaine does not possess anticholinergic properties and will not improve A-V transmission when atrial flutter or atrial fibrillation is present. 

Phenytoin lacks the anticholinergic properties of quinidine, disopyramide, and procainamide. However, the direct actions of phenytoin on the A-V node facilitate transmission. 

The antihistamine diphenhydramine (Benadry/), because it has anticholinergic properties, is used for mild parkinsonism and with the elderly, who may not be able to tolerate the more potent anticholinergics, levodopa, or the dopamine agonists. 

Diphenhydramine is known to be at least partially effective in Parkinson s disease, perhaps because of its anticholinergic properties. 

Geriatric Considerations - Summary Dexchlorpheniramine is a first-generation al-kylamine antihistamine with potent Hj-receptor antagonism. It has anticholinergic properties and can cause somnolence. Older adults taking this drug are at risk of dizziness and hypotension. 

Mechanism of Action A quaternary ammonium compound that has anticholinergic properties and that inhibits action of acetylcholine at postganglionic parasympathetic sites. Therapeutic Effect Reduces gastric secretions and urinary frequency, urgency, and urge incontinence. 

Anticholinergics and antihistamines chlorpheniramine (Chlor-Trimeton), diphenhydramine (Benadryl), hydroxyzine (Vistaril and Atarax), cyproheptadine (Periactin), promethazine (Phenergan), dexchlorpheniramine (Polaramine) All nonprescription and many prescription antihistamines may have potent anticholinergic properties. Nonanticholinergic antihistamines are preferred in elderly patients when treating allergic reactions. High... 

Promethazine (50 mg IM), an antihistaminic with sedative, antiemetic and anticholinergic properties is generally used in children as it causes little respiratory depression. 

Droperidol and hydroxyzine (25-50 mg IM) is sometime used for their antiemetic activity. Hydroxyzine has antianxiety, antihistaminic and anticholinergic properties also. 

Antihistaminics are better tolerated by elderly patients who do not tolerate anticholinergics. Antihistaminics do not cause blurring of vision and xerostomia and also possess some central anticholinergic properties. 

Antiparkinsonism effects Because of anticholinergic property, some antagonists have significant suppressant effect on the parkinsonism like symptoms. 

Antiparkinsonism Based on anticholinergic property, some H -antagonists such as diphenhydramine can be used in the early stages of treatment of parkinsonism. 

It has a direct action on intestinal musculature and having a weak anticholinergic property. It is used to treat acute and chronic diarrhoea. Adverse effects include addominal cramps and skin rash. 

Typical autonomic effects resulting from the anticholinergic properties of TCAs include the following ... 

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