Analgesics since their inception in sixteenth century have played an important role in providing symptomatic relief to the patient. Along with working on pain reduction, researchers have observed them to work on providing anxiolytic and sedative effect on the patient. But with the relief is associated the risk of getting used to or misusing the medication resulting in severe complications. The risk is more so in case of opoids owing to their effect on the reward centers of the brain.
Pathophysiology of opioid receptors
The problem is especially evident in Mu-opioid receptors that along with targetting analgesic effect are responsible for induction of tolerance and other adverse reactions like addiction and dependence. Other relatively harmless opioid receptors ( DOP, KOR, NOP) are not as effective as MOPs in analgesic effectivity; making it a tricky area to enter regarding pain relief without long term effect on patient’s health with safety.
With the advent of 2nd generation analgesics like Tapentadol, the pain relief mechanism has been furthur modified to suit analgesic needs of all types; making it important to understand whether the risk associated with the medication is greater or lesser than its analgesic strength and efficiency.
Let’s understand in brief about Tapentadole and Oxycodone before proceeding with their safety parameters.
Tapentadol and Oxycodone – Foreword
Introduced in 1980 by a German pharmaceutical company, Tapentadol belongs to the benzoid group of medications with a dual mode of action as it’s prominent characteristic. Tapentadol is unlike other opoids not a pro-drug making it a useful option for patients not responding to opiods with pro-drug feature as prima-basic. It is regarded as a moderately strong opioid with a potency in between that of Tramadol and Morphine ( opoids) and efficacy similar to Oxycodone analgesic.
Oxycodone, another German based semi-synthetic opiate is derived from ‘thebaine’ a plant based alkaloid. A first generation analgesic. Oxycodone has been in use since 1918 and declared an essential medication by WHO. Its potency has been postulated by researchers to be 1.8 times more than Morphine for total effect and 2.2 times for peak effect.
The improved efficiency with introduction of its controlled release form has resulted in a substantial increase of its use in the recent years especially in developed countries .
Does Tapentadol have less side-effects than Oxycodone
– Tapentadol vs Oxycodone for comparison of Respiratory effects
Respiratory depression is a serious side effects associated with injudicious use of opoids. To combat this issue, researchers are on the lookout for a safer option especially with regard to respiratory side effects.
Tapentadol and Oxycodone both are considered moderate analgesics with 100mg Tapentadol and 20mg Oxycodone showing equal efficiency traits. In order to understand their role in respiratory depression, a single 4 centre crossover study was find using healthy subjects. Those with positive alcohol breath test, positive pregnancy test or affirmed addicts were barred from the tests.
The subjects either received Tapentadol 100mg, Tapentadol 150 mg, Oxycodone 20 mg or placebo. Each participant randomly received all 4 treatments on four separate occasions at least a week apart. Subjects breathed through a facemask attached to a pressure transducer system and to three mass flow controllers for delivery of oxygen, carbon dioxide and nitrogen. The inspired and expired oxygen and carbon dioxide were measured at the mouth using capnograph. Heart rate and oxygen saturation were measured continuously throughout the study day.
Respiratory measurements without inspired CO2 and hypercapnic ventilatory response were obtained at strategic time periods. Subjects were queried regarding presence of symptoms like dizziness, dysphoria or euphoria in a questionnaire. Both Tapentadole and Oxycodone showed significant and long lasting respiratory depression following oral intake. For Tapentadol 150 mg dose showed 1.5 times larger intensity of respiratory depression than Tapentadol 100mg. Oxycodone had a significantly larger respiratory depressant effect than Tapentadol 100 mg but same magnitude of depressant effect in Tapentadole 150mg.
The study proved that Tapentadole produces less respiratory depression than Oxycodone at specific doses.
Study regarding Tapentadol safety profile
Traditional opioids like Oxycodone exert their analgesic effects through Mu-opioid receptors; contributing to 100% of the associated side effects. Tapentadol in comparison works through dual action of mu-opioid receptors with noradrenaline reuptake inhibitor effect resulting in fewer side-effects.
In a study conducted to evaluate the validity of the above postulates, pooled analysis from three trials were collected. Comparison was conducted between Tapentadol prolonged release with Oxycodone prolonged releasr tablets. Patients aged ≥75 years with with moderate to severe arthritic knee or low back pain were a part of the project.
The study project revealed tha incidence of gastrointestinal treatment emergent adverse effects, of nausea or vomiting were significantly lower in the Tapentadole PR group.
Apart from gastrointestinal issues, a comparison of bowel function was examined between Tapentadol immediate release, Oxycodone and placebo effects. Bowel function was better in patients using Tapentadol with lower use of laxatives recorded as well.
To confirm the reports, three randomised, multicentre, double blind trials on Tapentadole ER tablets were conducted. Patients diagnosed with moderate to severe chronic osteoarthritis or lower back pain were selected. The primary endpoint was a ≥ 30% pain relief without nausea, vomiting, constipation or discontinuation because of these effects.
After 12 weeks of treatment, patients administered Tapentadol PR achieved the ≥30% pain relief in comparison to Oxycodone recipients along with recorded achievement of quality of life. The results of the trials suggested that Tapentadole ER was associated with significantly better composite outcomes than Oxycodone CR.
Other advantages of Tapentadol
Tapentadol PR and Oxycodone were compared for postoperative pain treatment in orthopaedic trauma surgery in randomised, observer- blinded, active controlled clinical trials. Constipation rates were observed to be similar for both the medications in this particular trial. That said vomiting rates were significantly lower in Tapentadole than in Oxycodone ( 3% Tapentadol comparison to 8% Oxycodone).
In anothet Australia report for adverse effects evaluation of either medication, public case reports were extracted by Therapeutic Goods Association for Tapentadol and Oxycodone cases. 104 reports were in total found for Tapentadol as opposed to almost 249 reports for Oxycodone cases. That with studies proving improved cardiovascular profile with limited risk of abuse prove that Tapentadol use has significantly less Side-effects than Oxycodone. It can be safely used in patients with moderate to severe pain without the risk of serious side-effects.
Despite their effectiveness, the growing incidence of misuse associated with prescription painkillers is a problem that cannot be ignored. It is estimated that 18 women die everyday of a prescription painkiller overdose in the US with around 6600 deaths recorded since 2010. Earlier prevalent in men, now it is being observed on both the sexes to add to the complications.
In such cases it is the duty of both patient and practitioner to ensure the safe use of analgesic. Patients should use these medications judiciously and strictly under the guidance of the practitioner. That said, it is the duty of the practitioner as well to follow guidelines for responsible practicing and monitor the intake from their end to ensure safe use with a eventless withdrawal.