Mydriatics and cycloplegics

The answer is c. (Hardman, pp 156-158.) A wide variety of clinical conditions are treated with antimuscarinic drugs. Dicyclomine hydrochloride and methscopolamine bromide are used to reduce Gl motility, although side effects—dryness of the mouth, loss of visual accommodation, and difficulty in urination—may limit their acceptance by patients. Cyclopentolate hydrochloride is used in ophthalmology for its mydriatic and cycloplegic properties during refraction of the eye. Trihexyphenidyl hydrochloride is one of the important antimuscarinic compounds used in the treatment of parkinsonism. For bronchodilation in patients with bronchial asthma and other bronchospastic diseases, ipratropium bromide is used by inhalation. Systemic adverse reactions are low because the actions are largely confined to the mouth and airways. 

Cyclopentolate is an effective mydriatic and cycloplegic that begins to act very quickly and has a relatively short duration. It is used also in ophthalmoscopy for causing pre-operational mydriasis. Synonyms of this drag are mydrilate, cyclogyl, cyclomydril, pentolair, and others. 

The mydriatic and cycloplegic actions of atropine and scopolamine can persist for a week after topical application to the eye. Shorter-acting drugs, such as cyclopentolate and tropicamide, are now favored for this application because complete recovery of accommodation occurs within 6 to 24 hours and 2 to 6 hours, respectively. 

As mydriatic and cycloplegic agent Atropine is used to produce mydriasis and cycloplegia for testing errors of refraction. Mydriasis is required for fundoscopic examination and in the treatment of iritis and keratitis. 

Endocular inflammation. These inflammations usually generate synechia of the iris with the lens, which must be prevented by the instillation of mydriatic and cycloplegic collyrium. 

Because of its prolonged mydriatic and cycloplegic effect and relatively weak cycloplegic action, particularly in darkly pigmented irides, homatropine is not a drug of choice for fundus examination or cycloplegic refraction. Homatropine is primarily used in the treatment of anterior uveitis, in which its effects are similar to those of atropine. 

Prior application of a topical anesthetic appears to prolong the mydriatic and cycloplegic actions of tropicamide. It was reported that prior instillation of propara-caine 0.5% in blue-green eyes prolonged both the time required for 50% recovery to normal pupil size and the time during which mydriasis was maintained within... 

Because topical anesthetics increase permeability of the corneal epitheUmn to subsequently applied drugs, the clinical effectiveness of mydriatics and cycloplegics may be enhanced. 

Mydriatic and cycloplegic (e.g., cyclopentolate 2%, phenylephrine 2.5% every 15 minutes four times)... 

The mydriatic and cycloplegic activities of anticholinergics in humans are listed in Table 3.18. Atropine is recommended in situations requiring complete and prolonged relaxation of the sphincter of iris and the ciliary muscle. Mydriatics, like cyclopentolate, eucatropine, and homatropine bromide, with a shorter duration of action, are usually preferred for measuring refractive errors because of the relative rapidity with which their cycloplegic effects are terminated. 

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