Pharmaceutical waste can result from many activities and locations in a healthcare facility. If you have a compounding pharmacy on site, it generates drug waste. Anywhere medicines are employed can be the site of spills, half-used bottles, IV equipment with residual medicine on it. 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.
In the past, health care facilities would routinely flush waste pharmaceuticals down the drain. As a society we didn’t know how detrimental these drugs would be to the environment. Now biologists have found residual pharmaceuticals in fish and the aquatic ecology and we are understanding how bad the untreated disposal of drugs are. As responsible citizens and waste managers, we need to keep the Precautionary Principle in mind.
Pharmaceutical wastes can be hazardous under RCRA, but in many cases they are not. Solid pharmaceutical waste is generally easy to handle and package, but liquid waste poses more challenges in confining the waste and minimizing risk of release.
Unused medicines in their original unopened packages can often be returned to the supplier you bought it from. This is win-win. You don’t have to dispose of the drugs as waste and someone else who needs the medicine can use it.
Used transdermal patches. An increasingly popular way to administer medication is through a patch that sticks on the body and releases the drug through the skin. To maintain a more-or-less constant flowrate, the patch starts with substantially more medicine than it will ultimately deliver. A transdermal patch may contain 20 times the quantity of active ingredient the patient will get. After the patient removes the patch for good, it still has over 90 percent of the drug it started with.
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.
Pharmaceutical wastes can be hazardous the same way many chemicals are. They can be easily ignitable, corrosive, or highly reactive. Additionally, pharmaceutical wastes can be irritants to body tissues.
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.
Many common drugs that do not fit the criteria for RCRA hazardous waste include antidepressants, antihypertensives, hormones, and antibiotics. Although there is no special requirement that they be treated before disposal, healthcare facilities that have these items in their waste streams generally want to treat them to reduce liability. These can all be incinerated. Some medicines are not ideal for incineration. Especially those with non-active ingredients that do not burn easily. Dietary supplements containing heavy metals are also inappropriate for incineration. These can probably be put in the MSW stream, but encapsulation is also an alternative and the waste manager may choose this alternative just to be sure and to reduce liability.
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.
Alkaline hydrolysis is an un-nuanced blunt technology that destroys a lot of things. It is used to decompose animal carcasses. Given the unpopularity of incineration in many cases, the appeal of hydroysisi is clear. No air pollution, no chance of dioxin formation, no greenhouse gases, temperatures comparable to a kitchen (and hence less dangerous than an incinerator). For all practical purposes, both technologies effect that same level of sterilization. Alkaline hydrolysis results in a lot more secondary waste that must be dealt with - high pH liquid slurry and maybe solid residue versus incinerator ash. But there is also no air permit required.
Isolation leaves hazardous materials unchanged but prevents them from seeping into the environment. Encapsulation is accomplished with many plastics, resins, and even concrete. The medicines do not have to be removed from packaging. The process of “inertization” is similar. Medication (pills, this is not often used on liquid medication) are removed from packaging and mixed into a wet concrete. The concrete goes to the landfill. This isn’t perfect as it still allows leaching of the medicine in the landfill.
Remove the packaging from the pills (and that includes taking the pills out of blister packs).. Grind up the pills and mix with lime and cement and water into a paste. The WHO recommends putting the moist paste into the landfill before it dries, but there appears to be no reason for that, It could be allowed to dry before transport to the landfill. In any case this is thought to be safe enough to put into a sanitary landfill with municipal solid waste. Leaching is still a possibility, but it the landfill is a sanitary landfill, the chances of that should be reduced. (The WHO even recommends a ratio of 65 percent by weight medicine to 15 percent lime and 15 percent cement and 5 percent water.)
The UK government requires that cpntrolled drugs be denatured before disposal. Denature means changing the physical/chemical characteristics so the drug is ineffective.
Waste is considered hazardous because it either (1) contains materials on canonical lists - the F, K, P, and U lists - that are elaborated in the code of federal regulations, or (2) has the RCRA characteristics. The RCRA characteristics
The P-list includes eight chemical compounds used as drugs. These are "acutely hazardous" with a lethal dose (oral administration) of 50 mg/kg patient weight or less. The compounds are Warfarin (P001), Nitroglycerin (P081), Physostigmine (P204) and Physostigmine salicylate (P188), Nicotine (P075), Phentermine (P046), Arsenic trioxide (P012), and Epinephrine (P042). Waste Epinephrine is the most common of these in most hospitals.
The P-list includes 21 chemical compounds used as drugs.
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 applying the precautionary principle and intentionally erring on the side of safety. Dangerous drugs 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.
Drugs are used in treatment of cancer, but some drugs also can cause cancer - or at least increase the risk of cancer. The list of carcinogenic medicines includes some chemotherapy agents. Other chemicals used in healthcare settings can also cause cancer.
Carinogens pose a problem in medical waste and a risk for workers, patients, and visitors to health care facilities. Here is a list NIOSH developed of hazardous chemotherapy drugs.