Ismelin

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How does it work?

Guanethidine belongs to a group of medicines known as adrenergic neurone blockers. Guanethidine lowers blood pressure by preventing the release of the chemical messenger, noradrenaline, from nerve endings. It also depletes the nerve endings of noradrenaline. Normal blood pressure depends not only on the force with which the heart pumps blood round the body but also on the diameter of blood vessels and the volume of blood in circulation. Blood pressure is increased if the vessels are narrow or the volume of blood is high. Noradrenaline is a naturally-occurring chemical which contributes to the control of blood pressure by regulating the diameter of blood vessels and controlling heart rate. Guanethidine injection is used in the emergency treatment of hypertensive crises where rapid reduction of blood pressure is required.

What is it used for?

- Dangerously high blood pressure

Warning!

- This medicine may cause drowsiness. If affected do not drive or operate machinery.
- Discontinue this medicine before surgery.
- Careful monitoring is required during prolonged use of this medicine as it can lead to heart failure.

Use with caution in

- Asthma
- Decreased blood supply to the heart (coronary insufficiency)
- Disorder of blood flow to the brain (cerebral insufficiency)
- Moderately decreased kidney function
- Ulceration of the stomach or intestines

Not to be used in

- Heart failure
- Kidney failure
- People who have taken monoamine-oxidase inhibitor antidepressants (MAOIs) in the last 14 days
- Tumour of the adrenal gland (phaeochromocytoma)

This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy. If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

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