6. Conclusions

Of note, hepatotoxicity is considered when more than 4 gm of acetaminophen have been administered in 1 day [49], but there have been cases of liver injury occurring even at lower doses [50]; geared with this information, physicians should begin to re-evaluate their stance on acetaminophen being completely safe for use with patients at home, regardless of their liver

Adjuvant analgesics are defined as drugs with a primary indication other than pain that have analgesic properties in some painful conditions. The group includes numerous drugs in diverse classes. Although the widespread use of these drugs as first-line agents, the term "adjuvant" is a misnomer, they usually are combined with a less-than-satisfactory opioid regimen, in particular when administered for cancer pain. Some adjuvant analgesics are useful in several painful conditions and are described as multipurpose adjuvant analgesics (antidepressants, corticosteroids, α2-adrenergic agonists, neuroleptics), whereas others are specific for neuropathic pain (anticonvulsants, local anesthetics, N-methyl-D-aspartate receptor antagonists), bone pain (calcitonin, bisphosphonates, radiopharmaceuticals), musculoskeletal pain (muscle relaxants) or pain

Antidepressants, namely triclyclics (TCAs), which are used as adjuvants for pain management, can sometimes cause lethal cardiotoxicity as an ADR. In order to reduce the likelihood of this, the prescribing physician is advised to order an electrocardiogram in those patients with a history of heart disease, or simply provide a better tolerated alternative, such as desipramine and nortripltyline. Orthostatic hypertension, acute glaucoma and cognitive impairment are also ADRs caused by TCAs which can be avoided by screening patients for pre-existing conditions and previous episodes of these diseases in order to reduce the likelihood of a

Corticosteroids, although well tolerated at moderated doses, can cause ADRs such as increasing the risk of peptic ulcer disease at a higher prolonged dose. One way to ameliorate this side effect is by prescribing a gastro-protective formulation, hence reducing the possible damage to

Medications in the α2-adrenergic drug class (clonidine and tizanidine) are only used as a last resort adjuvant, due to their serious side effects [51] which include somnolence and hypotension. Olanzapine, along with other neuroleptics, are also used as an adjuvant only in cases where the patient is being treated for dementia or agitation. ADRs caused by olanzapine including tardive dyskinesia and neuroleptic malignant syndrome greatly reduce the quality of life of

Anticonvulsant drugs are now widely used to treat cancer-related neuropathic pain. Gabapentin and lamotrigine have both been proven to improve the condition of patients with neuropathic pain but these also cause side effects such as somnolence, dizziness and

health status and especially in the setting of long-term chronic pain management.

5. Adjuvant therapy

176 Pain Relief - From Analgesics to Alternative Therapies

reaction [51].

the gastric lining [51].

unsteadiness [51].

patients, which is undesirable [51].

from bowel obstruction (octreotide, anticholinergics).

Analgesics are essential pain relievers in modern medicine. However, analgesic misuse and their adverse effects can affect the efficiency of pain treatment and the eventual outcome could reduce the quality of life of patients. This review aims to highlight the most common adverse drug reactions of analgesic treatments and the possible safety risks involved with their use. Drug-drug interactions can be sometimes responsible for the adverse effects. However, a significant proportion of analgesic ADRs are preventable, which would reduce the patients' suffering. Acknowledging potential safety problems represents the first step for health professionals in assuring a safe and efficient analgesic treatment with minimum risks to patients. But being aware of the potential risks of the drugs should not be an impediment for health professionals to initiate analgesic therapy when necessary.
