Handling procedures for low and intermediate toxicity drug compounds are much less controlled than those of a potent nature, largely because their pharmacological effects, if exposed to, are less severe. Typically substances of this nature will have pharmacological effects when used in concentrations over 10mg/Kg. Low and intermediate toxicity drug compounds and their potential adverse health effects can be very well documented and have key properties which mean that they may frequently be handled on the open bench.
A low toxicity drug will often have good warning properties which are associated with “immediate” effects such as smell, or immediate irritation. These can assist in warning the scientist of impending exposure, and help to prevent working when conditions are unsafe. Should an over-exposure occur, the effects of low toxicity drugs are characteristically both treatable and unlikely to be chronic or severe. Typical OEL’s (occupational exposure limits) will be around 500ug/m3. The potential hazardous properties of these drugs will be well documented.
An intermediate toxicity drug will have a lower OEL, more in the range of 10-500ug/m³ and quite possibly result in a more severe effect following an exposure scenario. In some cases the effect(s) can be delayed and there may be a risk of sensitization. This means that after an initial level of exposure to the substance, a scientist can develop a more pronounced reaction to the compound when exposed to very low levels in the future.
As with low toxicity drugs, the effects of exposure to drugs of intermediate toxicity are typically treatable, may be moderately severe and are unlikely to be chronic.
On our next article, we will discuss category 3 and 4 of drug compounds: Potent and Highly Potent Drugs. If you have any suggestions on Laboratory Safety topics you would like us to discuss, please leave us a note on the comments below.