Clonazepam (Klonopin)

What clonazepam is

Clonazepam is a medication sold under the brand name Klonopin. It works by supporting GABA, a natural calming signal the brain uses to quiet overactive nerve activity, and it belongs to a group of medicines called benzodiazepines. It acts fairly quickly to calm the nervous system. Because the body can come to depend on it with longer use, it tends to be used thoughtfully and often for a defined purpose rather than indefinitely.

What it treats

Your clinician might suggest clonazepam for panic attacks and certain forms of anxiety, among other possible off-label uses. Clonazepam is also approved to treat certain seizure disorders, which is a general medical use rather than something our practice manages.

Whether it is a good fit depends on several factors, including your history, your other medications, and what you are working on. As with everything in psychiatry, that is decided case by case.

Who should not take clonazepam. FDA labeling lists a few firm exclusions. Clonazepam is not for anyone who has had an allergic reaction to a benzodiazepine, who has significant liver disease, or who has acute narrow-angle glaucoma, a type of glaucoma that comes on suddenly. People with the more common open-angle glaucoma may be able to take it if their glaucoma is being treated. Make sure your clinician knows your full medical history and medication list.

How it works

Honestly, no one knows with complete certainty how clonazepam produces its benefit. What research suggests is that it strengthens the effect of GABA, the brain's main calming messenger, which can settle a nervous system that is running too fast. The biology is only part of the picture: how much a medication helps, and how it feels, is individual. Two people on the same medication can have very different experiences.

How to take it

There is no single right way to take clonazepam; it depends on you and your clinician, and a medicine in this group calls for a bit more care than most. The plan you and your clinician make together is the one to follow, not a number you read online. A few points matter here:

• Take it exactly as you and your clinician agreed, and do not increase the amount on your own.
• Avoid alcohol, and do not combine it with opioid medicines (for pain or cough) or other sedating medications unless your clinician has said it is safe. Those combinations can dangerously slow your breathing.
• If you miss a dose, ask your clinician or pharmacist what to do rather than doubling up.
• Do not stop suddenly. With regular use the body adjusts to this kind of medicine, so stopping abruptly can cause withdrawal effects, and in some cases seizures. When the time comes to stop, your clinician can lower it gradually, which is safer and more comfortable.

A word on dependence, plainly: with steady use, the body can come to expect a benzodiazepine. That physical adjustment is common and expected, and it is not the same as doing something wrong. It does mean that stopping quickly can cause withdrawal, which can be serious. It is exactly why we plan any change together and step down slowly rather than all at once. Separately from physical dependence, medicines in this group carry a risk of misuse and addiction, which can lead to overdose, especially with alcohol or opioids.

What to expect

This varies from person to person. Unlike some medications that take weeks to help, clonazepam often has a calming effect fairly soon, which is part of why it is used the way it is. Any side effects, if they happen, also tend to show up early. Over time, the right plan for you may change, and that is something you and your clinician revisit together. If it does not turn out to be the right fit, that is useful information, not a dead end, and there are other options. As always, this is case by case.

Side effects

Not everyone gets side effects, and some, like sleepiness, often ease as your body settles, though effects on memory and thinking may not. The lists below are possibilities, not certainties.

Possible more common side effects:

• Drowsiness or sleepiness
• Dizziness or feeling unsteady on your feet
• Slowed coordination or reaction time
• Feeling foggy, or trouble with memory or concentration
• Tiredness

Because it can slow your reactions, do not drive or do anything that needs full alertness until you know how it affects you. If any of these stick around or bother you, send a non-urgent message through the patient portal or bring it up at your next visit; often a small change helps.

Less common, but concerning side effects that could require emergency care:

• Signs of an allergic reaction: rash, hives, or swelling of the face, lips, tongue, or throat, or trouble breathing or swallowing
• Severe drowsiness, very slow or difficult breathing, or being hard to wake, especially if it is combined with alcohol, an opioid, or another sedative
• New or worsening agitation, confusion, hallucinations (seeing or hearing things that others do not), or unusual changes in mood or behavior
• A seizure, or severe confusion, shaking, or seeing or hearing things that are not there after missing doses, lowering the dose, or stopping
• Any new or worsening thoughts of harming yourself

For any of these, use the help options at the top of this page: call 911 or go to the nearest emergency department for a medical emergency or severe reaction, or call or text 988 for a mental health crisis.

If agitation, confusion, or hallucinations are the concern, tell the clinicians treating you everything you take, including this medication. They may decide to stop it.

Pregnancy and breastfeeding

If you are pregnant, thinking about it, or breastfeeding, this is worth going through together rather than settling from a page. What follows is what the research currently shows. Tell your clinician before changing anything, and do not stop suddenly on your own, because stopping a benzodiazepine quickly can cause withdrawal.

In pregnancy

Information on clonazepam taken on its own in pregnancy is limited. A small number of studies of clonazepam alone have not found a higher chance of birth defects, and the risks may differ when it is taken together with other medicines. FDA labeling, looking at benzodiazepines as a group, notes that published studies do not show a clear link with major birth defects. It is not known whether clonazepam raises the chance of miscarriage. One study found a slightly higher chance at higher doses, and because miscarriage has many causes, that is hard to interpret. For scale, about 3 in 100 babies are born with a birth defect, before any particular exposure is considered.

A few other findings come up often enough to name:

• Preterm birth and growth. Two studies based on prescription records suggested a higher chance of preterm birth or low birth weight, but a filled prescription does not show whether the medicine was taken. Another study found a higher chance of babies being small for their stage of pregnancy, in people with and without epilepsy.
• Later learning and development. It is not known whether clonazepam affects later learning or behavior, and the findings so far are mixed. One study of 314 exposed children found a higher chance of intellectual disability and delayed milestones. Another, of 269 children, did not find a higher chance of autism. A study based on prescription records found no higher chance of autism or intellectual disability when clonazepam was used early in pregnancy for seizures, but did find a higher chance of intellectual disability when it was used for other reasons. Studies like these cannot always separate the medicine from the condition it was used for.

Symptoms in the newborn. Babies exposed late in pregnancy can have temporary symptoms after birth. FDA labeling describes two kinds. Sedation can show up as sleepiness, floppy muscle tone, or slowed breathing. Withdrawal can show up as irritability, restlessness, trembling, crying that is hard to settle, or trouble feeding. MotherToBaby adds trouble breathing, a bluish tinge to the skin, poor circulation, and very floppy muscle tone, and notes that some babies need time in the NICU. Not every exposed baby has them. The useful thing you can do is make sure the delivery team knows about the medication ahead of time, so someone is watching for it.

While breastfeeding

Clonazepam passes into breast milk, and it stays in the body a long time. The sources differ on what that means, so here is each one:

• FDA labeling asks that the benefits of breastfeeding be weighed against your need for clonazepam, and says babies exposed through breast milk should be watched for sleepiness, poor feeding, and poor weight gain.
• LactMed, the National Institutes of Health lactation database, says clonazepam occasionally causes sleepiness in breastfed babies, especially alongside other sedating medicines, and cites a safety rating that finds it possible to use with caution. Because clonazepam stays in the body a long time, LactMed prefers a shorter-acting medicine when possible.
• MotherToBaby says clonazepam passes into milk in small amounts, can cause sleepiness, and might build up in a baby's body, so a shorter-acting medicine might be preferred with a newborn or a baby who is only breastfed. It also says the benefits may outweigh the possible risks.

Call the pediatrician if your baby seems unusually sleepy, feeds poorly, is not gaining weight as expected, or seems slow to reach milestones. Watching for these matters most in younger babies who are only breastfed, and when more than one psychiatric medication is involved.

If you are a man taking clonazepam

Human studies have not looked at whether clonazepam affects male fertility or the chance of birth defects; one study in male rats suggested it might affect sperm. In general, a father's medication use is unlikely to raise risks to a pregnancy.

Registries

FDA labeling for clonazepam points to the North American Antiepileptic Drug Pregnancy Registry, which follows pregnancies exposed to seizure medicines, including clonazepam. You can enroll yourself rather than waiting to be asked. It is listed in the references at the bottom of this page.

When to reach out, and where

For routine questions, side effects that can wait, or how things are going, send your clinician a message through the patient portal. These are part of your ongoing care and are answered in the normal course of a few business days, so they are best for things that are not urgent.

If something feels urgent, you do not need to wait for a reply. The help options at the top of this page are the fastest way to get care: 911 or the nearest emergency department for a medical emergency or severe reaction, or 988 any time for a mental health crisis or thoughts of self-harm.

Questions to ask your clinician

• What are you hoping clonazepam will help with in my case?
• How and when will we know if it is working?
• How does this fit with the other parts of my plan?
• What should I avoid while taking it?
• What is the plan if this one turns out not to be the right fit?
• How will we handle stopping it, if and when we get there?