Topical ocular clonidine has been found to reduce intraocular pressure up to 30%, while reducing systemic blood pressure up to 10%. The eyedrops are moderately well tolerated and produce miosis in the treated and contralateral eye. Local ophthalmic use of clonidine appears to be limited because of reduced ophthalmic arterial and episcleral venous pressure when concentrations are greater than 0.125%.

References And Further Reading

Banner W, Jr, Lund ME, Clawson L. Failure of naloxone to reverse clonidine toxic effect. Am J Dis Child 137: 1170, 1983.

Hodapp E, et al. The effect of topical clonidine on intraocular pressure. Arch Ophthalmol 99: 1208, 1981.

Kaskel D, Becker H, Itudolf H. Early effects of clonidine, epinephrine, and pilocarpine on the intraocular pressure and the episcleral venous pressure in normal volunteers. Graefes Arch Clin Exp Ophthalmol 213: 251, 1980.

Kosman ME. Evaluation of clonidine hydrochloride (Catapres). JAMA 233: 174–176, 1975.

Krieglstein GK, Langham ME, Leydhecker W. The peripheral and central neural actions of clonidine in normal and glaucomatous eyes. Invest Ophthalmol Vis Sci 17: 149, 1978.

Lee DA, Topper JE, Brubaker RF. Effect of clonidine on aqueous humor flow in normal human eyes. Exp Eye Res 38: 239, 1984.

Mathew PM, Addy DP, Wright N. Clonidine overdose in children. Clin Toxicol 18: 169, 1981.

Petursson G, Cole R, Hanna C. Treatment of glaucoma using minidrops of clonidine. Arch Ophthalmol 102: 1180, 1984.

Turacli ME. The clonidine side effect in the human eye. Ann Ophthalmol 6: 699, 1974.

Van Joost TN, Faber WR, Manuel HR. Drug-induced anogenital pemphigoid. Br J Dermatol 102: 715, 1980.

continued long after discontinued use of diazoxide. The cause of this unusual phenomenon is unknown. Cove et al reported (along with a case in the National Registry) blindness secondary to hypotension from a rapid decrease of blood pressure in malignant hypertension, with presumed ischemia of the optic nerve. An increase in eyelashes can occur with generalized hypertrichosis due to diazoxide. The 2006 Physicians’ Desk Reference reports a transient cataract in an infant. Lens changes have been described in beagle dogs (Schiavo et al 1975).

References And Further Reading

Burton JL, et al. Hypertrichosis due to diazoxide. Br J Dermatol 93: 707–711, 1975.

Cove DH, et al. Blindness after treatment for malignant hypertension. BMJ 2: 245–246, 1979.

Crandall DC, Leopold IH. The influence of systemic drugs on tear constituents. Ophthalmology 86: 115, 1979.

McEvoy GK (ed). American Hospital Formulary Service Drug Information 87, American Society of Hospital Pharmacists, Bethesda, p 809–812, 1987.

Neary D, Thurston H, Pohl JEF. Development of extrapyramidal symptoms in hypertensive patients treated with diazoxide. BMJ 3: 474, 1973.

Physicians’ Desk Reference, 60th edn, Thomson PDR, Montevale NJ, pp 3031–3032, 2006.

Schiavo DM, Field WE, Vymetal FJ. Cataracts in beagle dogs given diazoxide. Diabetes 24: 1041–1049, 1975.

Thomasen A et al. Clinical observations on an antihypertensive chlorothiazide analogue devoid of a diuretic activity. Can Med Assoc J 87: 1306, 1962.

Generic name: Guanethidine monosulfate.

Generic name: Diazoxide.

Proprietary names: Hyperstat, Proglycem.

Primary use

This non-diuretic benzothiadiazine derivative is used in the emergency treatment of malignant hypertension.

Ocular side effects

Systemic administration

Certain

1. Lacrimation

Possible

1. Eyelids or conjunctiva

a.Allergic reactions

b.Erythema

2. Decreased vision

3. Oculogyric crises

4. Subconjunctival or retinal hemorrhages secondary to druginduced anemia

Conditional/Unclassified

1. Optic nerve infarction

2. Transient lens changes

Clinical significance

Ocular side effects due to diazoxide are uncommon except for increased lacrimation, which occurs in up to 20% of patients taking this agent. In some instances, the lacrimation

Proprietary name: Ismelin.

Primary use

This adrenergic blocker is effective in the treatment of moderate to severe hypertension.

Ocular side effects

Systemic administration

Certain

1. Decreased vision

2. Non-specific ocular irritation

a.Hyperemia

b.Photophobia

c.Edema

3. Horner’s like syndrome

a.Miosis

b.Ptosis

Possible

1. Decreased intraocular pressure

2. Subconjunctival or retinal hemorrhages secondary to drug-induced anemia

3. Photophobia

Clinical significance

Ocular side effects from oral guanethidine are rare and seldom of clinical significance although Brest et al (1962) reported an incidence of ‘blurring of vision’ in 17% of patients taking 70 mg of this drug per day. Some patients have a slight transitory ptosis, miosis and conjunctival hyperemia. The drug is probably secreted in the tears.