Guanethidine/MAOIs
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:
Severe. These medicines may interact and cause very harmful effects and are usually not taken together. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.
How the interaction occurs:
Your MAOI may prevent your guanethidine from working properly.
What might happen:
You may experience a life-threatening increase in blood pressure.
What you should do about this interaction:
Let your healthcare professionals (e.g. doctor or pharmacist) know right away that you are taking these medicines together. If your doctor prescribes these medicines together, you may need to monitor your blood pressure. Also, let your doctor know if you have any headaches or vision changes. These can be signs of increased blood pressure.Your healthcare professionals may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.
References:
1.Ismelin (guanethidine monosulfate) UK summary of product characteristics. Amdipharm September 30, 2005.
2.Nardil (phenelzine sulfate) US prescribing information. Parke-Davis May, 2007.
3.Ramsay RR, Dunford C, Gillman PK. Methylene blue and serotonin toxicity: inhibition of monoamine oxidase A (MAO A) confirms a theoretical prediction. Br J Pharmacol 2007 Nov;152(6):946-51.
4.Peter C, Hongwan D, Kupfer A, Lauterburg BH. Pharmacokinetics and organ distribution of intravenous and oral methylene blue. Eur J Clin Pharmacol 2000 Jun;56(3):247-50.
