Like most drugs that are available generically, lorazepam is made by more than one manufacturer.
Lorazepam 1mg, for example, is made by no less than 7 different manufacturers, including:
- Aurolife Pharma, LLC
- Major Pharmaceuticals Inc
- Mylan Pharmaceuticals Inc.
- Leading Pharma, LLC
- Teva Pharmaceuticals USA
- Bausch Health (formally Valeant Pharmaceuticals)
- PD-Rx Pharmaceuticals, Inc.
Leading Pharma, LLC produces generic lorazepam while Bausch Health (which used to be Valeant Pharmaceuticals) produces brand name Ativan (which contains the active ingredient lorazepam).
Below is the complete ingredient list for both products:
Leading Pharma, LLC Lorazepam 1mg
- Lorazepam 1mg
- Lactose monohydrate
- Magnesium Stearate
- Microcrystalline Cellulose
- Polacrilin potassium
Bausch Health Ativan 1mg
- Lorazepam 1 mg
- Lactose anhydrous
- Microcrystalline cellulose
- Polacrilin potassium
- Magnesium stearate
So, the only difference between these two products is the type of lactose used (lactose monohydrate vs. lactose anhydrous).
This brings up the natural question of whether or not there is any difference between these two.
The first thing to point out is that lactose is used in both of these products as an inactive ingredient, which, by definition, do not have any pharmacological effect but are rather used as fillers, disintegrants, etc...:
"Inactive ingredients are described as pharmaceutical necessities and excipients that are used to manufacture drug products. An inactive ingredient is any component of a drug product other than the active ingredient. Examples are: fillers, tablet lubricants and binders, disintegrating agents, colorants, flavoring agents, preservatives, suspending agents, and sweeteners."
Additionally, both of these lorazepam products are considered 'therapeutically equivalent' to each other. In other words, they have the same rate and extent of absorption (within a statistical margin of error).
What this means is that they can be substituted for one another by your pharmacy (subject to state laws) since they will have the same pharmacological effect.
So, it is important to remember that there really shouldn't be a difference with these two different lorazepam products, they should produce the exact same (or at the very least, near-similar) effects.
Anhydrous Lactose Vs. Lactose Monohydrate
Since you asked specifically about lactose, there is a difference between anhydrous lactose and lactose monohydrate.
Lactose monohydrate is also known as α-Lactose monohydrate.
α-Lactose is in a 'crystalline state' and is associated with one molecule of water (i.e. lactose monohydrate). On average, the water content of α-lactose monohydrate is about 5%.
α-lactose monohydrate is very commonly used in pharmaceuticals as an excipient (i.e. inactive ingredient). It can be used as a filler and is often used in tablets due to its easy compressibility. It is also commonly used in dry-powder inhalers.
Anhydrous lactose, sometimes referred to as β-lactose, is made by a similar process as α-lactose monohydrate but is produced using higher temperatures (above 200F) and does not contain water.
Anhydrous lactose is also commonly used as a filler due to its easy compressibility.
There are several academic papers which discuss the difference between these two forms of lactose in more detail (such as 'Lactose, Anhydrous' and 'Lactose: Some basic properties and characteristics') but for the purposes of this answer, you can consider them as not significantly different.
They both are stable and, for the most part, chemical inert (i.e. don't react with other substances).
In regards to your question of whether or not you can take these two lorazepam products together, the answer is that you should not. You should only take one or the other.
Remember that these products are considered therapeutically equivalent and will have the same effects. If you took both together, that would be essentially the same as doubling your dose (i.e. overdosing).
You should just stick with one or the other when dosing.
The only difference in ingredients between Leading Pharma lorazepam 1mg and Bausch Health (Valeant Pharma) lorazepam 1mg is the type of lactose they contain. Bausch Health Ativan (lorazepam) 1mg contains anhydrous lactose while Leading Pharma lorazepam 1mg contains lactose monohydrate. While there is a slight difference between anhydrous lactose and lactose monohydrate, they are both used as excipients (i.e. inactive ingredients) in lorazepam products and are chemically inert.
- Ativan Prescribing Information. Baush Health
- Leading Pharma Lorazepam Monograph. PubMed
- Evaluation of Anhydrous α-Lactose, A New Excipient in Direct Compression. Taylor & Francis Online
- Lactose Some basic properties and characteristics. DFE Pharma
- Lactose, Anhydrous. ScienceDirect
- Lactose in Pharmaceutical Applications. Drug-Dev
- Drugs@FDA Glossary of Terms. FDA