In this Article

• What is guanethidine (Ismelin)?
• What are the possible side effects of guanethidine (Ismelin)?
• What is the most important information I should know about guanethidine (Ismelin)?
• What should I discuss with my healthcare provider before taking guanethidine (Ismelin)?
• How should I take guanethidine (Ismelin)?
• What happens if I miss a dose (Ismelin)?
• What happens if I overdose (Ismelin)?
• What should I avoid while taking guanethidine (Ismelin)?
• What other drugs will affect guanethidine (Ismelin)?
• Where can I get more information?

What should I discuss with my healthcare provider before taking guanethidine (Ismelin)?

You cannot take guanethidine if you

• have pheochromocytoma;
• have congestive heart failure; or
• are taking a monoamine oxidase inhibitor such as isocarboxazid (Marplan), phenelzine (Nardil), or tranylcypromine (Parnate).

Before taking this medication, tell your doctor if you

• have peptic ulcer disease (stomach ulcers) or another stomach disease;
• have gallstones,
• have kidney disease;
• have any type of heart disease;
• have asthma;
• have ulcerative colitis;
• are suffering from depression (especially if you have suicidal thoughts); or
• are receiving electroconvulsive shock therapy.

You may require a dosage adjustment or special monitoring during treatment if you have any of the conditions listed above.

Guanethidine is in the FDA pregnancy category C. This means that it is not known whether guanethidine will be harmful to an unborn baby. Do not take guanethidine without first talking to your doctor if you are pregnant or could become pregnant during treatment.

Guanethidine passes into breast milk and may be harmful to a nursing infant. Do not take guanethidine without first talking to your doctor if you are breast-feeding a baby.

How should I take guanethidine (Ismelin)?

Take guanethidine exactly as directed. If you do not understand these directions, ask your pharmacist, nurse, or doctor to explain them to you.

Take each dose with a full glass of water.

Take guanethidine with food or milk if it causes stomach upset.

It is important to take guanethidine regularly to get the most benefit.

Do not stop taking guanethidine suddenly without first talking to your doctor. This could cause severely high blood pressure, nervousness, and anxiety.

Your doctor may want you to have blood pressure monitoring or other medical evaluations during treatment with guanethidine to monitor progress and side effects.

Store this medication at room temperature away from moisture and heat.