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Clinicopathologic Reports, Case Reports, and Small Case Series
July 2001

Prophylaxis of Vasovagal Reaction With Atrohist Plus

Arch Ophthalmol. 2001;119(7):1079-1080. doi:

Vasovagal reactions (VVRs) can present a treatment dilemma for medical professionals, and fear of causing such reactions can prevent ophthalmologists from performing necessary examinations. Atenolol, midodrine hydrochloride, paroxetine, fludrocortisone acetate, as well as salt and fluid intake have demonstrated efficacy in treating the disorder.1 Other vasoconstrictors and selective serotonin reuptake inhibitors are being studied, but to our knowledge, there are no medications to prevent isolated incidents of VVR with known triggers.2 We describe 2 patients who experienced VVRs on applanation tonometry or instillation of dilating drops. subsequent reactions were prevented with oral Atrohist Plus (a combination of phenylephrine hydrochloride, phenylpropanolamine hydrochloride, chlorpheniramine maleate, hyoscyamine sulfate, atropine sulfate, and scopolamine hydrobromide; Vintage Pharmaceuticals Inc, Charlotte, NC) administered 1 hour prior to examination.

Report of Cases

Case 1

A 41-year-old healthy man with an ocular history of myopia and a family history of glaucoma was seen for complaints of decreased visual acuity for several months. After instillation of a fluorescein sodium–benoxinate hydrochloride solution, the applanation tonometry demonstrated the intraocular pressure (IOP) of 21 mm Hg OU, and immediately after tonometry, the patient fainted. Owing to lightheadedness, he refused additional drops for dilation. The undilated fundus examination revealed a cup-disc ratio of 0.50 U. The patient was followed as a glaucoma suspect, and after each IOP measurement, he felt faint, sweaty, or lightheaded. On one occasion, he experienced a severe VVR, became lightheaded, tremulous, diaphoretic, and fainted. Blood pressure and pulse were measured immediately following this presumed VVR and were found to be normal, 134/84 mm Hg and 74 bpm, respectively. No formal testing for VVR was performed.

Repeated IOP examinations were indicated, but additional tonometry measurements incurred a high risk of another syncopal episode. Since there are no oral medications identified in the literature to prevent isolated incidents of VVR, intravenous atropine was suggested by a cardiologist. As an alternative to the intravenous medication, Atrohist Plus was selected, and 1 tablet was administered to the patient 1 hour prior to tonometry measurement. Applanation tonometry was performed, and the patient did not experience any symptoms of VVR. One tablet of oral Atrohist Plus was administered 1 hour prior to his next 3 office visits, and no symptoms of VVR were reported.

Case 2

A 21-year-old healthy man with no medical problems was known to experience a VVR and faint after the instillation of dilating drops. The patient had an ocular history of myopia and contact lens wear and was seen for a comprehensive examination and laser in situ keratomileusis consultation. One tablet of Atrohist Plus was administered approximately 1 hour prior to the eye examination. A complete eye examination was performed, including applanation tonometry followed by instillation of dilating drops (1% tropicamide and 2.5% phenylephrine). No symptoms of VVR were reported.


Predictable VVRs and fainting during tonometry or instillation of eye medications are uncommon occurrences but may force the ophthalmologist to choose between a comprehensive eye examination and an adverse event. The use of the oral medication, Atrohist Plus, can be a useful tool in the prevention of VVR when the ophthalmologist is aware of the precipitating factor. The primary indication for use is for relief from irritation of sinus, nasal, and upper respiratory tissues owing to its vasoconstrictive properties and subsequent drying of the mucosa. The drug is contraindicated in patients receiving monoamine oxidase inhibitors, patients with asthma, patients younger than 12 years, women who may be pregnant, or patients with known hypersensitivity to antihistamines or sympathomimetics. In addition, acute angle-closure glaucoma may be precipitated by the dilating effects of this oral medication; therefore, narrow angles should be ruled out before its administration.3

Atrohist Plus presumably prevents VVRs through the anticholinergic effects of atropine, hyoscyamine, and scopolamine and the adrenergic effects of phenylephrine and phenylpropanolamine. The anticholinergics act by blocking acetylcholine at the muscarinic receptors in smooth muscle, cardiac muscle, and sinoatrial and atrioventricular nodes as well as in exocrine glands, resulting in increased heart rate and blood pressure and decreased heart block. Phenylephrine acts primarily on α-1 adrenergic receptors in arterial smooth muscle to cause vasoconstriction, while phenylpropanolamine acts on both α-1 and 2 and β-1 receptors to cause vasoconstriction as well as increased heart rate, contractility, and cardiac output. The combination of medications most likely acts by preventing the bradycardia and hypotension associated with VVR.4

Corresponding author: Norbert Becker, MD, Cook County Hospital, 1835 W Harrison, Chicago, IL 60612(e-mail: www.genevaeye.com).

Calkins  H Pharmacologic approaches to therapy for vasovagal syncope.  Am J Cardiol. 1999;8420Q- 25QGoogle ScholarCrossref
White  CMTsikouris  JP A review of pathophysiology and therapy of patients with vasovagal syncope.  Pharmacotherapy. 2000;20158- 165Google ScholarCrossref
 Atrohist Plus [package insert].  Charlotte, NC Vintage Pharmaceuticals2000;
 Drug Information for the Health Care Professional. Vol 1.  Greenwood Village, Colo Micromedex2001;