7 Clonidine Interactions You Should Know About

Clonidine (Catapres) is a medication that’s FDA approved to treat high blood pressure. But it’s not typically used unless other medications aren’t working. That’s because it can cause significant side effects, like drowsiness and low blood pressure. And these side effects can become worse when it’s taken with certain medications.

Even so, clonidine is used off-label for several other uses, like hot flashes and nicotine dependence. An extended-release (ER) clonidine (Kapvay) is an option for attention-deficit hyperactivity disorder (ADHD). No matter the reason for taking clonidine, drug interactions are still possible. So, which ones should you know about? Let’s discuss. 

7 clonidine interactions to know about

The list below discusses some important clonidine interactions. But there are also other medications not on this list that can interact. As always, talk to your healthcare provider before starting a new medication. They can determine if there are serious issues.

1. Tricyclic antidepressants

​​Tricyclic antidepressants (TCAs) are antidepressants used to treat anxiety and depression. Some can also prevent migraines or treat insomnia. Examples include amitriptyline, nortriptyline (Pamelor), and imipramine.

TCAs can cause a number of side effects, including sedation (drowsiness or sleepiness). When taken together, TCAs and clonidine can make you too drowsy. Dry mouth, dizziness, and constipation may also be worse.

TCAs can also make clonidine less effective at controlling your blood pressure. In this case, your healthcare provider may increase your clonidine dosage. They might also recommend a different antidepressant that’s less likely to interact.

Promotion disclosure

Clonidine

Avg retail price

$2.38(Save Free%)

GoodRx discount

$2.38

See all discounts

How it works

Use GoodRx to find medications, pharmacies, and discounts.

GoodRx discounts can help you pay less for your prescription.

Bring your free coupon or savings card to the pharmacy.

2. Antipsychotic medications

Antipsychotic medications are used to treat conditions like schizophrenia and bipolar disorder. Examples include quetiapine (Seroquel), clozapine (Clozaril), and risperidone (Risperdal). They can cause many side effects, including several that overlap with clonidine.

Combining clonidine with antipsychotic medications can make you more drowsy. And you may experience more dizziness or lightheadedness when changing positions (like going from sitting to standing). This is due to a drop in blood pressure, which may cause you to faint or fall down.

If you need to take this combination, be sure to change positions slowly. This can help your body adjust to the blood pressure changes. Otherwise, your healthcare provider may adjust your medications to manage this interaction. 

3. Calcium channel blockers

Calcium channel blockers (CCBs) are used to treat conditions like high blood pressure and chest pain. Some also treat heart rhythm problems. Examples of CCBs include diltiazem and verapamil. Both of these medications can slow down your heart rate. 

On its own, clonidine can also slow down your heart rate. And combining it with diltiazem or verapamil can slow it down too much (called bradycardia). Your blood pressure may also drop too low.

In some cases, bradycardia can be serious and may require hospitalization. So your healthcare provider may avoid this combination. But if not, they may want to monitor your heart rate during treatment. Let them know right away if you experience symptoms of bradycardia. These include an irregular heartbeat, shortness of breath, and/or extreme tiredness.

4. Beta blockers

Like CCBs, beta blockers can treat conditions like high blood pressure, chest pain, and heart rhythm problems. Examples include metoprolol (Lopressor, Toprol XL), propranolol (Inderal), and carvedilol (Coreg).

Beta blockers slow down your heart rate. This effect can be intensified if they’re taken with clonidine. Watch for signs and symptoms of bradycardia with this combination.

In some cases, your healthcare provider may have you take clonidine with a beta blocker. But special caution needs to be taken when stopping these medications. They’ll have you follow a specific tapering schedule to avoid a rapid rise in blood pressure. Don’t attempt to stop taking these medications on your own.

5. Digoxin

Digoxin (Lanoxin) can treat conditions like heart failure and atrial fibrillation. It causes your heart to pump stronger every time it beats. And it also slows down your heart rate. When combined with clonidine, digoxin can cause your heart rate to get too low. 

Digoxin isn’t used as often due to serious side effects and drug interactions. And it requires special monitoring, too. But if you need to take it with clonidine, your healthcare provider may want to monitor your heart rate more closely.

6. Medications that cause drowsiness

As mentioned above, clonidine can make you feel drowsy. This effect can be stronger when combined with other medications that cause drowsiness.

Examples of other medications with sedative effects include:

• Benzodiazepines, like lorazepam (Ativan)

• Sleep medications, like zolpidem (Ambien)

• Opioids, like oxycodone

• Barbiturates, like phenobarbital

Your healthcare provider may need to adjust your regimen to avoid problems with this interaction. They may also suggest changing medications. 

Let them know if this combination is making you too drowsy. Get immediate medical attention if your drowsiness is severe, or if your breathing rate is too slow.

7. Alcohol

​​Alcohol can also cause drowsiness. It has similar effects on the brain as other medications that cause drowsiness.

Taking alcohol and clonidine can make you too drowsy. This combination can be even more dangerous if you’re driving or operating machinery. So it’s best to minimize or avoid alcohol while you’re taking clonidine.

When should I contact my healthcare provider about a clonidine interaction?

​​If you're worried about a potential clonidine interaction, talk to your healthcare provider. Even if you don’t need to change your medications, it’s a good idea to check.

They may already know about interactions with clonidine. Sometimes, medications are still prescribed even if there’s an interaction. Not all interactions are serious. Some may just need extra monitoring.

Talk to your healthcare provider if you’re having symptoms that bother you or seem worrisome. This could include too much drowsiness, dizziness, or tiredness. Severe symptoms may warrant immediate medical attention.

How can I avoid or manage potential interactions with clonidine?

Talking to your healthcare provider or pharmacist is the best way to manage clonidine interactions. They can review your current medication list for any issues. They can also suggest medication changes as needed.

It’s also a good idea to be open and honest with them about how much alcohol you drink. Some medications, including clonidine, can be unsafe with alcohol. They can tell you how much alcohol is safe to drink in your specific situation.

Why trust our experts?

Written by:

Austin Ulrich, PharmD, BCACP

Austin Ulrich, PharmD, BCACP, is a board-certified ambulatory care clinical pharmacist. In his early career, he provided direct patient care in a variety of settings, including hospital and community pharmacies, and in a primary care clinic as a clinical pharmacist.

Edited by:

Alyssa Billingsley, PharmD

Alyssa Billingsley, PharmD, is the director of pharmacy content for GoodRx. She has over a decade of experience as a pharmacist and has worked in clinical, academic, and administrative roles.

Reviewed by:

Amy B. Gragnolati, PharmD, BCPS

Amy Gragnolati, PharmD, BCPS, is a pharmacy editor for GoodRx. Amy currently holds her pharmacist license in Georgia and California.

Our editorial standards

Meet our experts