I know that valium contains muscle relaxing properties that other benzos do not
All benzodiazepines contain muscle relaxing properties. Classical Benzodiazepines are all non-selective which means that they ALL have anxiolytic, hypnotic, anti-seizure, muscle relaxant and amnesiac properties but just to different levels. For instance Diazepam does have powerful muscle relaxant effects, more so than most but every benzo still possesses that effect.
To the OP: I'm sure you know the first of this...
All benzodiazepine agonists exert five primary effects and they are:
1. Hypnotic
(Prescribed for: short-term management of insomnia)
2. Anxiolytic
(Prescribed for: treatment of anxiety disorders and phobias; prevention of panic attacks)
3. Anti-convulsant/anti-seizure
(Prescribed for: seizure control; management of status epileptics; prevention of panic attacks)
4. Antispasmodic (Muscle relaxant)
(Prescribed for: treatment of muscle spasms, for example, Tetanus or spastic disorders and Restless legs syndrome.
5. Amnesic
Used as sedatives for patients receiving mechanical ventilation, or those in extreme distress or severe pain. Midazolam is the most common and effective for sleep-induced procedures.
Different benzodiazepines exhibit these primary effects to varying degrees. For example, diazepam (Valium) is a relatively powerful hypnotic, whereas the more modern benzodiazepines such as alprazolam (Xanax), lorazepam (Ativan), and clonazepam (Klonopin) are less powerful hypnotics, but are very powerful anxiolytics. Do not assume that because one benzodiazepine makes you sleepier than another that this benzodiazepine is more potent than those that don’t produce sleepiness to the same degree.
There are six GABA-a subunits, GABA(a 1), GABA(a 2), GABA(a 3), GABA(a 4), GABA(a 5) and GABA(a 6). Of those six receptors, benzodiazepines have no affinity for (a 4) and (a 6). Most effective anti-anxiety benzodiazepines have affinity to both alpha1 and alpha2 subunits while the more effective hypnotics have higher affinity to just the alpha1 subunit
GABA-A receptor subtype containing:
Alpha1: sedation, amnesiac, alcohol interaction
Alpha2: anxiolysis, muscle relaxation
Alpha3: anxiolysis, muscle relaxation, sedation
Alpha5: amnesiac, anti-seizure
The alpha1-containing has been proposed to be responsible for the sedative action; the alpha2 and/or the alpha3 subtypes have been suggested to mediate the anxiolytic activity and the myorelaxation effects, and the alpha5 subtype has been associated with cognition processes and possible anti-seizure capability when combined with the alpha1 subtype.
All benzodiazepines are anxiolytics. How their effects vary in degree are due to their compound structures. The following:
7-nitro compounds (Clonazepam, Nitrazepam, Flunitrazepam) are potent anti-seizure and muscle relaxants.
3-hydroxy compounds (Lorazepam, Temazepam, Oxazepam) are often more sedating, often hypnotics and have more prominent muscle relaxant effects.
Imidazo compounds (Midazolam, Loprazolam) are powerful amnesics, very sedating and short acting. Also analgesic. They are also water soluble.
Triazolo compounds (Alprazolam, Triazolam, Estazolam) are often sedating, mostly hypnotic and very short acting, have short half-lives. They are very potent on a mg basis.
2-Keto compounds (Diazepam, Flurazepam, Chlordiazepoxide) exert all the five primary effects to a noticeable but various degree and have very long half lives.
