Suhera M Aburawi
University of Tripoli, Libya
Title: Effect of ion channel blockers on pharmacological action of paracetamol using albino mice
Biography
Biography: Suhera M Aburawi
Abstract
Introduction: Paracetamol is one of the most widely used drugs as antipyretic and analgesic for mild to moderate pain. Currently,
paracetamol is the fi rst-line of choice for pain management and antipyresis. Ion channels are involved in many cellular processes;
drugs acting on ion channels have long been used for the treatment of many diseases.
Objective: To evaluate the eff ect of voltage gated ion channel blockers on analgesic activity of Paracetamol.
Material & Methods: Th e central antinociceptive activity was determined by hot plate test and formalin test (Phase I), using male
albino mice. Anti-infl ammatory activity was determined by formalin test (Phase II). Seven groups of mice were used. Group 1:
control group (1% T80); group 2: treated with (200mg/kg) paracetamol; group 3: treated with diff erent ion channel blockers; group 4:
received combined treatment of ion channel blockers and paracetamol; group 5: received standard drugs as Aspirin (200mg/kg) for
formalin test or tramadol (5mg/kg) for hot plate test. Intraperitoneal injection was adopted.
Results: Pain produced by noxious stimuli (heat and formalin) was signifi cantly reduced by acute administration of paracetamol.
Infl ammation pain produced by formalin injection was signifi cantly decreased by acute administration of paracetamol. Nifedipine
has signifi cant decrease in nociceptive pain (hot plate and formalin test, phase I) and infl ammatory pain (formalin test, phase II).
Verapamil did not produce analgesic or anti-infl ammatory eff ects. Phenytoin produced signifi cant decrease in nociceptive pain using
hot plate test and decrease infl ammatory pain in formalin test (Phase II), while phase I is not sensitive for phenytoin. 4-aminopyridine
produces signifi cant decrease in nociceptive and infl ammatory pain. Combined treatment of nifedipine and paracetamol has
antinociceptive and anti-infl ammatory eff ects but less than the additive eff ect. Verapamil administration with paracetamol produces
antinociceptive and anti-infl ammatory activity. Th is eff ect is due to paracetamol only. Administration of combined treatment of
phenytoin and paracetamol has antinociceptive action and anti-infl ammatory eff ect but less than the additive eff ect which may
reach the ceiling.Th e combined treatment of 4-aminopyridine and paracetamol showed antinociceptive action, 4-aminopyridine
potentiates the eff ect of paracetamol; while the anti-infl ammatory action was less than the additive eff ect.
Conclusion: Paracetamol has central analgesic and anti-infl ammatory eff ect. Nifedipine, phenytoin and 4-aminopyridine, each
alone, produce analgesic and anti-infl ammatory action. Verapamil, in the dose used, by its self has neither analgesic nor antiinfl
ammatory eff ect. Paracetamol analgesic action is not aff ected by nifedipine or phenytoin; it may be concluded that the combined
treatment may reach the ceiling eff ect of analgesic action, while analgesic eff ect of paracetamol is potentiated by 4 aminopyridine.
Combined treatment of nifedipine, phenytoin or 4-aminopyridine with paracetamol produce anti-infl ammatory eff ect, which less
than the additive eff ect. Ceiling eff ect of anti-infl ammatory activity may be produced by combined administration of paracetamol and
nifedipine, phenytoin or 4-aminopyridine. Hot plate model is more sensitive to the eff ect of analgesic agent that relieve neuropathic
pain compared to formalin test (phase I).