^ why do you say there probably will be 'less-complete cross-tolerance'?
You're of course correct that it has a thiophene ring rather than a benzene ring but it still binds non-selectively to the benzodiazepene receptors (the ionotropic GABAa receptor protein complex) and is a full-agonist just like classic benzodiazepines.
That's not to say that you're incorrect in recommending caution, I am just curious what informed that statement.
As laC mentioned, 1mg of etizolam is equivalent to .5mg of alprazolam or .5mg clonazepam/10mg diazepam (if you are more familiar with other benzodiazepines, you can find equivalencies here.
Please be careful however because, as I and others who have used etizolam pills have found, there can be a degree of variance in the potency of the pills. They may be in sealed blister packs marked "1mg" but are produced in areas with less stringent production controls than the FDA and other western regulatory agencies. In JUST my personal experience, they are fairly consistent but occasionally I've come across pills of marked decreased OR increased potency.
Abrupt or over rapid withdrawal from etizolam as with benzodiazepines may result in the appearance of the benzodiazepine withdrawal syndrome, including rebound insomnia.[8] A neuroleptic malignant syndrome, a rare event in benzodiazepine withdrawal has been documented in a case of abrupt withdrawal from etizolam.[9]
1. Patients with generalized anxiety disorder were either treated with Etizolam (0.5 mg), Alprazolam (0.5 mg), or Bromazepam (3 mg) twice a day. While all three drugs retained their effectiveness over two weeks, etizolam actually started to become more effective than the other benzos from to 2 weeks to 4 weeks (reverse tolerance in a way). The researchers also note antidepressant activity in etizolam not seen in the other two drugs tested. [10] PubMed Etizolam in the treatment of generalized anxiety disorder
2. No cognitive deficits over 3 weeks compared to placebo were noticed with etizolam 0.5 mg BID, a curious finding for a BZD agonist [11] PubMed 0. Effects of treatment with etizolam 0.5 mg BID on cognitive performance
3. When multiple doses of etizolam or lorazepam were administered to rat neurons, lorazepam caused downregulation of alpha-1 BZD sites (aka tolerance/dependence), while etizolam caused an increase in alpha-2 BZD sites (aka reverse tolerance to anti-anxiety effect).
Also, the researchers noted a marked tolerance over time to the anticonvulsant effects of lorazepam, but no significant tolerance to anticonvulsant effects of etizolam.
Quote from abstract: "These data suggest that etizolam is endowed with a reduced liability to induce tolerance and dependence compared with classical benzodiazepines." [12] Low tolerance and dependence liabilities of etizolam
Every -diazepine that is widely used is slightly different from others in their affinity for certain GABAa subunits. While some may have more pronounced sedative/hypnotic and amnestic effects (e.g. midazolam) due to stronger affinity for α1 and/or α5 subunits, others will have more pronounced anxiolytic effects (e.g. diazepam) due to stronger affinity for α2 and/or α3. All of the subunits can produce an anticonvulsant effect.
Due to variance in subunit affinities, there will be a degree of incomplete cross tolerance between benzodiazepines just like there are with opioids or any class of drug but from my understanding of how etizolam and benzodiazepines work, there will not be less complete cross tolerance between etizolam and any benzodiazepine than how much exists between various benzodiazepines in general.
In the studies you mentioned, they demonstrated that they had the same efficacy in treating seizure activity and anxiety as other benzodiazepines, so they suggest that they can be used interchangeably with benzodiazepines for the same indications (due to the same receptor activity as I mentioned) so I would avoid inferring that due to the possibility of a reduction in tolerance and dependence that they would be less cross tolerant.
The main reason I wanted to clarify this is because if someone is heavily physically dependent on benzodiazepines and read that there may be less complete cross tolerance, they may erroneously believe they have to take MORE etizolam than they do to avoid seizures and other withdrawal symptoms.
Those studies you mentioned are very interesting and promising and I hope that this is investigated further because those two are rather limited. The first one only involved 45 patients (a mere 15 of which were taking etizolam) and the second involved rats and strictly looked at the anticonvulsant activity. With stories of people already experiencing nasty withdrawal from etizolam despite the short time it's been so widely available recreationally (the long-term effects of which will undoubtedly be characteristically different than low-dose therapeutic use), I'd hate for people to get the impression that it is safe. I don't at all mean to imply that you were suggesting that, I just wanted to add a bit more context. Admittedly, I haven't searched for meta-analyses or anything, so there might be more information on this out there. If anyone has links to more studies, I'd be very interested!
I do certainly apologize for hijacking this thread, OP. Listen to everyone above though, start low and go slow