Klonopin and Xanax are both benzodiazepines and help relieve symptoms of anxiety. Klonopin is specifically used in the treatment of panic disorder and is also effective at controlling seizures. The effects of Klonopin last longer than Xanax, which means Klonopin does not need to be taken as frequently throughout the day. Xanax requires regular dosing to keep blood levels constant. Both drugs can cause physical and psychological dependence, particularly when taken at higher dosages for longer periods of time; however, more severe withdrawal and rebound reactions have been reported with Xanax on discontinuation. Effectiveness and side effects (such as sedation and dizziness on standing) are similar. Activity of Xanax is affected by race (people of Asian descent achieve higher concentrations and activity of Xanax lasts longer), concurrent liver or kidney disease, alcoholism and obesity.
What are Klonopin and Xanax?
Klonopin is the brand (trade) name for clonazepam and Xanax is the brand name for alprazolam.1,2 Although both belong to the class of drugs known as benzodiazepines, so work in a similar way, there are structural differences between them that can affect how they work in the body.
Which one works quicker or lasts longer?
Xanax is usually more quickly absorbed than Klonopin with peak concentrations occurring within 1-2 hours following administration, compared to 1-4 hours for Klonopin, although speed of absorption varies from person to person.1,2 Effects of Xanax last on average 4 to 6 hours although, once again, there are wide variations between individuals. Effects of Klonopin can last for up to 12 hours in adults.1,2,3
Because Klonopin acts for a longer time in the body, it doesn’t need to be dosed as frequently as Xanax. Xanax, however, requires regular administration to keep blood levels constant.1,2,4,5
Activity of Xanax is affected by race (people of Asian descent achieve higher concentrations and activity of alprazolam is longer), concurrent liver or kidney disease, alcoholism and obesity. Less is known about differences in absorption and activity between individuals administered Klonopin.1,2
What dose of Klonopin equals 0.5mg of Xanax?
Benzodiazepine equivalency tables state that 0.5mg of alprazolam (Xanax) is approximately equivalent to 0.5mg clonazepam (Klonopin).4 However, people of Asian descent metabolize Xanax differently to people of other races, and certain disease states such as alcoholism, liver and kidney disease, obesity and even old age can affect how Xanax behaves in the body; so benzodiazepine equivalency tables should be used as a guide only as they do not reflect individual variation.1,2,3,4 In addition, liver disease and possibly some other medical conditions may affect how quickly Klonopin is eliminated from the body.
Which drug is more effective?
Few trials have directly compared Klonopin with Xanax. One reported no significant difference between the two drugs in terms of side effects (sedation, dizziness on standing) or effectiveness when both were used for the treatment of panic disorder.6
Which drug is more likely to cause dependence?
Both Klonopin and Xanax have the potential to cause both physical and psychological dependence. Susceptibility to dependence varies depending on dose taken, regularity of consumption, and genetic factors. It is not clear whether risk of dependence is higher with some benzodiazepines compared with others.7
Some people can form dependencies to benzodiazepines after as few as 14 days of regular use. Following six months of continuous use, more than 50% of people are classed as dependent. Benzodiazepines should not be stopped suddenly; dosages need to be slowly tapered off over several weeks to months to avoid withdrawal reactions. All addiction-prone individuals should be under careful surveillance if they need to be prescribed benzodiazepines.4,7
Are withdrawal symptoms more severe with Xanax?
Yes. Reviews suggest discontinuation from Xanax is particularly difficult and is associated with more serious rebound and withdrawal symptoms.5 Compared to Klonopin, Xanax has a much shorter half-life (9-20 hours for Xanax compared to 19-60 hours for Klonopin).4,5,6 Half-life is a technical term for the time it takes for 50% of an administered drug to leave your body – it is not the same as duration of effect. The blood levels of drugs with longer half-lives tend to remain relatively more constant in the body, and tend to cause much less severe withdrawal symptoms than dramatic fluctuations seen with benzodiazepines with a shorter half-life such as Xanax.
Withdrawal symptoms may include agitation, convulsions, hallucinations, tremor, abdominal and muscle cramps. More severe withdrawal symptoms are likely in people who have taken larger dosages over an extended period of time.
Which drug is safer long term?
Although Klonopin is indicated for the treatment of panic disorder, and for certain types of seizures, few trials have evaluated its use long-term. Experts advise doctors monitor the usefulness of Klonopin periodically, and consider gradual discontinuation if the drug appears ineffective.1 Xanax should only be used short-term.1,2,3
How do Klonopin and Xanax work?
Both Klonopin and Xanax, like all benzodiazepines, enhance the actions of a neurotransmitter in the brain called GABA (gamma-aminobutyric acid).1,2 This neurotransmitter can reduce the activity of nerve cells, so enhancing it has a calming effect which can improve symptoms of anxiety, reduce muscle tension, stop seizures, and induce sleep. Benzodiazepines are also known for their amnesic effect – or ability to disrupt short-term memory – and this makes them useful before surgery. Because of structural differences, some benzodiazepines are more likely than others to make you sleepy, relieve anxiety, stop seizures, relax muscles, or make you forget.1,2,3 Xanax is FDA approved for anxiety-relief, and is less likely than some other benzodiazepines (such as diazepam or temazepam) to induce sleep. Klonopin is also useful to treat anxiety-related symptoms, and is FDA approved for the treatment of panic disorder. It is also less likely than some other benzodiazepines to induce sleep. Its anti-seizure effects are stronger than Xanax, so may be used to treat certain types of seizures, such as variants of Lennox-Gastaut syndrome, akinetic or myoclonic seizures.1,3
- Klonopin (clonazepam) [Package Insert] Revised 12/2013 Genentech https://www.drugs.com/pro/klonopin.html Accessed 03/2016
- Xanax (alprazolam) [Package Insert] Revised 03/2015 Pharmacia and Upjohn Company https://www.drugs.com/pro/xanax.html Accessed 03/2016
- Clonazepam. Pubchem. Open Chemistry Database Revised 03/2016 https://pubchem.ncbi.nlm.nih.gov/compound/clonazepam
- Benzodiazepine equivalency table Revised April 2007 http://www.benzo.org.uk/bzequiv.htm Accessed 03/2016
- Tesar GE. High-potency benzodiazepines for short-term management of panic disorder: the U.S. experience. J Clin Psychiatry. 1990 May;51 Suppl:4-10; discussion 50-3.
- Tesar GE, Rosenbaum JF, Pollack MH, et al. Double-blind, placebo-controlled comparison of clonazepam and alprazolam for panic disorder. J Clin Psychiatry. 1991 Feb;52(2):69-76.
- Benzodiazepine Dependency and Withdrawal. Benzo.org.uk. http://www.benzo.org.uk/FAQ1.1.htm
- Klonopin Drug Information
- Xanax Drug Information
- Alprazolam Drug Information
- Clonazepam Drug Information
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