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Ocuhist ophthalmic

Sympathomimetics (Direct, Mixed-Acting)/Guanethidine

This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug or commencing any course of treatment.

Medical warning:

Moderate. These medicines may cause some risk when taken together. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.

How the interaction occurs:

When these two medicines are taken together, your body may not process guanethidine properly.

What might happen:

The beneficial effects of guanethidine may decrease and cause an increase in your blood pressure.

What you should do about this interaction:

Contact your healthcare professionals (e.g. doctor or pharmacist) about taking these two medicines together. They may already be aware of this interaction and may be monitoring you for it. If you experience headache, dizziness, or blurred vision, contact your doctor. Your dose of guanethidine may need adjusting. Do not start, stop, or change the dosage of any medicine before checking with them first.

References:

1.Laurence DR, Nagle RE. The effects of bretylium and guanethidine on the pressor responses to noradrenaline and angiotensin. Br J Pharmacol 1963; 21:403-13.
2.Muelheims GH, Entrup RW, Paiewonsky D, Mierzwiak DS. Increased sensitivity of the heart to catecholamine-induced arrhythmias following guanethidine. Clin Pharmacol Ther 1965 Nov-Dec;6(6):757-62.
3.Gulati OD, Dave BT, Gokhale SD, Shah KM. Antagonism of adrenergic neuron blockade in hypertensive subjects. Clin Pharmacol Ther 1966 Jul-Aug; 7(4):510-4.
4.Sneddon JM, Turner P. The interactions of local guanethidine and sympathomimetic amines in the human eye. Arch Ophthalmol 1969 May; 81(5):622-7.
5.Spiers AS, Calne DB. Action of dopamine on the human iris. Br Med J 1969 Nov;4(679):333-5.
6.Misage JR, McDonald RH Jr. Antagonism of hypotensive action of bethanidine by "common cold" remedy. Br Med J 1970 Nov 7;4(731):347.
7.Ober KF, Wang RI. Drug interactions with guanethidine. Clin Pharmacol Ther 1973 Mar-Apr;14(2):190-5.
8.Cooper B. "Neo-synephrine" (10%) eye drops. Med J Aust 1968 Aug 31; 55(2):420.

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