Pilocarpine actions

Cushny has compared the action of d- and Z-hyoscyamines with that of atropine, and of d-homatropine with that of dZ-homatropine in antagonising the action of pilocarpine, and finds that the order of activity of the first three is in the ratio 1 40 20, and of the second two in the ratio 4 2-5. He drew attention also to the important influence of the acyl radical in the tropeines, which exercises the maximum effect when it is a hydroxyalkyl aromatic residue and is laevorotatory and in illustration of this point gives the following table of relative activities on the basis of capacity to antagnonise pilocarpine in the salivary fistula dog —... 

The same author found Z-hyoscine sixteen to eighteen times as active as the d-isomeride in antagonising the action of pilocarpine on the termination of nerves in the salivary glands, -while both isomerides are equally active on nerve ends in striated and unstriated muscle and on the central nervous system. 

The construction of d-pilocarpine was effected by converting d-Aomopilopoyl chloride (VI COjH COCl) into diazomethyl drhomo-pilopyl ketone (VIII), transformation of the latter by the action of hydro-... 

Pilocarpine is being less used in medicine as a diaphoretic in dropsy and similar diseases because of its depressant action on the heart. It has also been employed as a substitute for physostigmine to contract the pupil and reduce intraocular pressure. It has been used as an antidote to atropine, but it does not antagonise the action of atropine in the central nervous system. 

Drug delivery problems associated with pilocarpine, most notably low ocular bioavailability and short duration of action, continue to be significant (44). In an effort to prolong delivery and to avoid undesirable effects, an investigation was carried out on the incorporation and in vitro release of pilocarpine from a soluble film... 

Pilocarpine acts by stimnlating mnscarinic receptors, therefore making it similar in action to acetylcholine when systematically introduced. This compound differs from acetylcholine in that it does not react with any nicotinic receptors, but by stimulating the CNS. Its effects are blocked by atropine. It has found therapeutic use in ophthalmology as a myotic agent. Synonyms are pilopine, isopto carpine, and atmocaprine. 

Systemic antidotes They produce the action which are opposite to that of poison e.g. caffeine for morphine and atropine for pilocarpine. 

The first generation of cholinomimetics, such as arecoline, bethanecol and pilocarpine, were not designed for the treatment of AD and the results of the early clinical trials were consistently disappointing. In addition to their poor bioavailability and short duration of action, any therapeutic benefits were limited by their cholinergic side effects. The second generation of muscarinic... 

Actions Applied topically to the cornea, pilocarpine produces a rapid miosis and contraction of the ciliary muscle. The eye undergoes a spasm of accommodation, and vision is fixed at some particular distance, making it impossible to focus (Figure 4.7). [Note the opposing effects of atropine, a muscarinic blocker, on the eye (see p. 45).] Pilocarpine is one of the most potent stimulators of secretions such as sweat, tears, and saliva, but it is not used for this purpose. 

Actions of pilocarpine and atropine on the iris and ciliary muscle of the eye. 

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