This article describes possible interactions with guanfacine oral tablet. Interactions can cause a drug to have a different effect on the body than expected. Interactions can occur due to medications, alcohol, or certain health conditions.
To find coupon options for guanfacine and to learn more about the drug, including its uses, see this article.
Guanfacine comes as tablets that you’ll swallow. It’s also available as extended-release tablets that you swallow. (Extended-release means the drug slowly releases into the body over time.)
Other drugs and guanfacine
Drugs that may interact with guanfacine oral tablet are listed below. This article doesn’t include all drugs that may interact with guanfacine.
Drugs that may interact with guanfacine oral tablet include:
- benzodiazepines:
- drug examples: alprazolam (Xanax), clonazepam (Klonopin)
- what might happen: can increase the risk of side effects of guanfacine and the benzodiazepine
- certain antibiotic drugs:
- drug examples: ciprofloxacin (Cipro), clarithromycin
- what might happen: can increase the risk of side effects of guanfacine
- certain antiepileptic drugs:
- drug examples: carbamazepine (Tegretol, others), phenytoin (Dilantin)
- what might happen: can make guanfacine less effective
- certain antifungal drugs:
- drug examples: ketoconazole, itraconazole (Sporanox, Tolsura)
- what might happen: can increase the risk of side effects of guanfacine
- certain drugs used for treating heart conditions:
- drug examples: diltiazem (Cardizem CD, others), verapamil (Verelan, others)
- what might happen: can increase the risk of side effects of guanfacine
- certain drugs used to treat HIV:
- drug examples: cobicistat (Tybost), efavirenz
- what might happen: depending on the drug, can increase the risk of side effects of guanfacine or can make guanfacine less effective
- certain drugs used to treat prostate cancer:
- drug examples: apalutamide (Erleada), enzalutamide (Xtandi)
- what might happen: can make guanfacine less effective
- tricyclic antidepressants:
- drug examples: nortriptyline (Pamelor), amitriptyline
- what might happen: can make guanfacine less effective
- ceritinib (Zykadia):
- what might happen: can increase the risk of side effects of guanfacine
Questions about guanfacine and interactions
Here you’ll find answers to some common questions about guanfacine and possible interactions.
Can I take magnesium with guanfacine?
Yes, if your doctor agrees it’s safe for you to do so. Magnesium supplements and guanfacine aren’t known to interact.
That said, talk with your doctor before taking a magnesium supplement. Magnesium supplements can interact with other medications and health conditions. Your doctor can help determine if it’s safe for you to take supplements.
Can I take cold medications with guanfacine?
It depends. There are many different types of drugs for treating cold symptoms. Certain cold medications are safe to take with guanfacine, while others may not be.
For example, taking certain antihistamines, such as cetirizine, with guanfacine can increase the risk of certain side effects, including drowsiness. Taking the cough medication dextromethorphan and guanfacine can raise your risk of hallucinations (seeing or hearing things that aren’t really there). This is a rare but serious side effect either medication can cause on its own.
Before taking cold medications with guanfacine, talk with your doctor or pharmacist. They can recommend safe options that lower the risk of interactions with guanfacine.
When to avoid guanfacine
Certain health conditions or other factors could increase some risks with guanfacine oral tablet. Because of this, doctors may not prescribe guanfacine in these cases. These health conditions or other factors are called contraindications.
Here’s a list of contraindications for guanfacine oral tablet:
- Past allergic reaction to guanfacine. If you’ve had an allergic reaction to guanfacine oral tablet in the past, taking guanfacine oral tablet may cause another allergic reaction.
Before starting treatment with guanfacine, tell your doctor if the above relates to you. They can recommend whether you should take guanfacine.
Alcohol and guanfacine
Guanfacine oral tablet is known to interact with alcohol.
Taking guanfacine oral tablet and drinking alcohol may cause:
- drowsiness
- dizziness
If you drink alcohol, talk with your doctor about whether it’s safe to consume it during your treatment with guanfacine oral tablet.
Other interactions and guanfacine
Interactions can occur with supplements, foods, vaccines, and some lab tests. Below you can learn whether guanfacine oral tablet has these interactions.
The information below doesn’t include all other possible interactions with guanfacine.
Guanfacine and supplements
Before taking guanfacine oral tablet, tell your doctor and pharmacist about any herbs you take, as well as vitamins and supplements. Doing so may help you avoid possible interactions.
If you have questions about interactions that may affect you, talk with your doctor or pharmacist.
Guanfacine interactions with herbs
Guanfacine oral tablet may interact with St. John’s wort. This herb is often used to relieve symptoms of depression.
Taking guanfacine and St. John’s wort may cause guanfacine to be less effective.
Because of this, ask your doctor or pharmacist before taking any herbs during treatment with guanfacine oral tablet.
Guanfacine interactions with vitamins
Guanfacine oral tablet isn’t known to interact with any vitamins. But this doesn’t mean interactions with vitamins can’t happen or won’t be identified later.
Because of this, ask your doctor or pharmacist before taking any of these products during treatment with guanfacine oral tablet.
