Waste drugs or pharmaceuticals can pose a special treatment and management challenge. Small quantities at households can often be thrown away in the municipal waste stream (perhaps with some makeshift method of denaturing or making the drugs undesirable to interlopers). Large quantities kept at pharmacies, distribution centers, hospitals, etc. must be managed to minimize the risk of release or to exposure to workers and the public.
This category of waste includes expired, unused, and contaminated pharmaceutical products including vaccines and biological products used for therapy. Prescription and over-the-counter drugs end up as pharmaceutical waste as does paraphernalia used in pharmacies: gloves, masks, bottles, etc.
Pharmaceuticals encompass a huge range of chemical compounds and they have all sorts of different effects on humans, animals, and plants. You need to be careful with all of them. Even aspirin should not be flushed down the toilet. Some medicines, such as those used to treat cancer, are outright dangerous (genotoxic or cytotoxic) and healthcare workers have to be protected from exposure.
What characteristics can make pharmaceutical wastes hazardous or dangerous? The RCRA characteristics
Additionally, pharmaceutical wastes can have these effects on humans and animals:
Some drugs are genotoxic or mutagenic - aside from being dangerous to release to the environment, these can cause cancer and reproductive problems in healthcare workers. Medical facilities that deal with cancer treatment produce carcinogenic and/or teratogenic waste.
There are exceptions for household waste, but enterprises (commercial and non-profit alike) cannot dispose of drugs by putting them in the municipal waste stream for delivery to a landfill. In the US, the EPA’s Land Disposal Restriction requires treatment of pharmaceuticals before disposal.
Treatment is aimed at changing the chemical structure of the medicines. The treated medicine should be acceptable for disposal with no worries of it getting into the ecosystem and harming people. While any number of chemical reactions could be proposed and systems devised to deliver those reactions (think of a gant artificial liver)., a more foolproof, all-encompassing solution is incineration.
Incineration induces chemical reactions, too. Combustion is oxidation of anything that will burn, and most pharmaceuticals are organic compounds that will burn with sufficient temperature, oxygen, and time. A few drugs such as arsenic oxide are inorganic.
Incineration is thus an appealing option for the waste management engineer with a heterogeneous waste stream, as many streams with pharmaceuticals tend to be
Alkaline hydrolysis (mixing with a strong solution of sodium hydroxide) can also work on a wide range of pharmaceuticals. The system never gets hot and avoids the problems incinerators can come with (e.g. ash, acid gases in the flue stream, need to cool flue gas.)
Because the reactants and their products do not go into the gas phase, the kinetics of the oxidation can be slower and inadequate mixing may limit the effectiveness of the destruction.
Isolation leaves potential hazardous material unchanged but prevents it from makes it difficult to get to. Encapsulation is accomplished with many potential plastics, resins, and even concrete.
The UK government requires that cpntrolled drugs be denatured before disposal. Denature means changing the physical/chemical characteristics so the drug is ineffective.
In the United States the federal government regulatedsRCRA hazardous waste and facilities that generate waste on a regular basis are classified by size of waste stream
Large Quantity Generators (LQGs) = facilities that generate more than 1,000 kg of hazardous waste per month
Small Quantity Generators (SQGs) = facilities that generate between 100 kg (approximately 220 lbs) and 1,000 kg of hazardous waste per
Conditionally Exempt Small Quantity Generators (CESQGs) = facilities that generate less than 100 kg of hazardous waste per month
Most US hospitals are CESQGs or SQGs.
Waste is considered hazardous because it either (1) contains materials on canonical lists, or (2) has certain characteristics.
Chemotherapy medicines are notoriously dangerous, but only nine chemotherapy drugs are either P- or U- listed chemicals. These nine were in use in 1976. Therefore, over 100 equally hazardous chemotherapy drugs currently in use today are not identified federally as hazardous waste and are not subject to the RCRA Subtitle C requirements. However, a good deal of chemotherapy waste must be managed as hazardous waste.
Mineral preparations with heavy metals can be classified as hazardous waste.
Medical waste managers often consider non-RCRA waste as hazardous waste when it contains pharmaceuticals even though this is not legally necessary. They are intentionally erring on the side of safety. Dangerous drugs with an LD50 less than 50 mg/kg are usually incinerated, as are waste antidepressants, antibiotics, and high blood-pressure medications. Waste hormones and endocrine disruptors (from any source) cause concern and are often burned before final disposal.
Here is a list NIOSH developed of hazardous chemotherapy drugs.