Look for evidence that the medication is either working or not and for possible adverse reactions. Some warning signs include a decreased appetite, depression, loose bowels or vomiting. Handle the medicines prescribed for animals with the same precautions as human drugs. While humans and animals may use some of the same drugs, use of a human drug in an animal should not be considered without veterinary guidance. Humans should never take an animal's medication.
Some human medications can have fatal effects when given to an animal and vice versa.
Treating animals with medications without a veterinarian's advice can be ineffective or detrimental. The pharmacist discouraged people from keeping prescription medications when they are no longer needed. Over time, the drug's effectiveness may deteriorate and the toxicity may increase. Unused medications, such as narcotic pain killers, should not be treated casually. When medicines become old or if the patient dies, any remaining prescribed medication should be destroyed.