Pentazocine-opioid antagonist and its pharmacology

Introduction

The first mixed agonist and antagonist analgesic to be marketed. It is an agonist at the kappa and sigma opoid receptor and has a weak antagonist action at the mu receptor.

Therapeutic Uses

-Pentazocine is used to treat pain.

Side effects

-Diarrhea

-Fever

-Joint and muscle pain.

-Painful or difficult urination

-Sore throat

-Shortness of breath

-Chest pain

Pharmacokinetics

Bioavailability                                 20% orally

Metabolism                                      Hepatic

Onset of action                                15min

Biological half-life                            2 to 3 hours

Excretion                                            Renal     

    

Mechanism of action

The preponderance of evidence suggests that pentazocine antagonizes the opioid effects by competing for the same receptor sites, especially the opioid mu receptor.

Drug-drug interaction

1-Pentazocine+Acepromazine= It may increase the hypotensive activities of                                                                           

                                                          Pentazocine.

2-Pentazocine+Amphetamine= It may increase the analgesic activities of                        

                                                        pentazocin.

3-Pentazocine+Amiloride= The risk or severity of adverse effect can be increase.

4-Pentazocin+Azelastine= Pentazocine may increase the centralnervous system 

                                               depressant activities of azelastin

.REFERENCE:

Tripathi K.D,"Essentials of medical pharmacology",7th edition,page no 479,480,482