Does NAC (N-Acetylcysteine) Help with Benzodiazepine Tapering and Withdrawal?

Does NAC help with benzodiazepine withdrawal?

Nobody knows. N-acetylcysteine (NAC) has never been properly tested in people who are tapering a benzodiazepine, so there is no evidence that it helps, and any benefit is unproven. The human testing that exists was done for other conditions, some of them addictions.

A patient who took a benzodiazepine exactly as prescribed is in a different situation. The nervous system adapted to the medication. That is physical dependence, and dependence is not addiction. It calls for a slow taper, and no supplement replaces one.

What is NAC, and why do patients ask about it?

NAC is a modified form of the amino acid cysteine, and the body uses it to make glutathione, one of its main antioxidants. Under the name acetylcysteine, it is a prescription medicine for acetaminophen overdose and for thinning mucus in the lungs. It is also sold over the counter as a supplement.

Patients ask about it because of glutamate, the brain’s main excitatory chemical. In Chapter III of the Ashton Manual (benzo.org.uk), Professor C. Heather Ashton described what happens when a benzodiazepine is removed too quickly: nearly all the excitatory mechanisms in the nervous system go into overdrive.

In laboratory work, NAC appears to affect glutamate signaling. So, on paper, it looks like a match for what happens in the brain during withdrawal. Unfortunately, paper is as far as it goes.

Claims that NAC improves sleep, calms anxiety, or shortens withdrawal for people coming off a benzodiazepine have nothing behind them. The same chapter of the Manual says there is “no general need for dietary supplements or extra vitamins or minerals,” and that all of these can be harmful in excess. What patients report differs: some say NAC takes the edge off, and others notice nothing or feel worse.

No supplement lowers the risk of a withdrawal seizure.

NAC is sometimes said to prevent withdrawal seizures. Nothing supports that claim. Seizure risk in benzodiazepine withdrawal is managed by the rate of the taper, and by nothing on the supplement shelf.

In its 2020 update to the benzodiazepine boxed warning, the United States Food and Drug Administration (FDA) said that stopping abruptly or reducing the dose too quickly can cause withdrawal reactions, including seizures, which can be life-threatening. In Chapter III, Professor Ashton wrote that seizures are extremely rare with slow dosage tapering.

A person who reduces faster because a capsule feels like protection is in more danger, not less. Call emergency services for a seizure or any other medical emergency.

Why does the prescriber need to know about a supplement?

First, a supplement has effects of its own and can interact with other medications. NAC taken by mouth can cause nausea, which is also a withdrawal symptom, so one can be mistaken for the other.

Second, the symptoms that send a person to the supplement aisle are information. A surge of anxiety or a run of sleepless nights after a reduction often means the step was too large or came too soon. Covering that with a capsule is like turning up the radio to drown out a noise from the engine.

The answer is a change to the taper, worked out with the prescriber, such as a longer hold or a smaller next step. It is not another pill.

NAC is not forbidden. For Dr. Mark Leeds, an osteopathic physician and deprescribing specialist in Fort Lauderdale, Florida, there is no blanket list of banned or approved supplements. The decision is made per patient, with a physician who understands the pharmacology, and a separate article covers which supplements help with benzodiazepine withdrawal.

Fortunately, what eases withdrawal is already known.

What eases withdrawal is a gradual taper, directed by the patient. Chapter II of the Ashton Manual describes steps of up to one tenth of the dose, with the patient as the best judge of the pace. The Maudsley Deprescribing Guidelines describe a hyperbolic pattern, in which reductions get smaller as the dose gets lower.

That takes months, and sometimes a year or more. For a minority of patients, Professor Ashton wrote in Chapter III, symptoms linger for months or even years after the last dose. They ease with time, and no supplement has been shown to hurry that.

Dr. Leeds’ practice does one thing: medically supervised benzodiazepine and z-drug tapering for patients in Florida, at a pace the patient sets. Questions about NAC, or any other supplement, belong in that conversation. Patients in Florida who want a slow, supervised taper can contact the office.

This article is educational. It is not medical advice, and reading it does not create a doctor-patient relationship. Decisions about starting, continuing, or tapering any medication should be made with your own physician.