Interaction between Tramadol and Cetirizine
Moderate Synergy

ID DDInter1841 and DDInter343
Interaction Concurrent use of cetirizine or levocetirizine with alcohol or other agents that exhibit central nervous system (CNS) depressant effects may result in additive impairment of mental alertness and performance.
abdominal distension abdominal pain abscess acute pancreatitis adenocarcinoma amyloidosis anaemia aneurysm angioedema Aching joints More
Management Concomitant use of cetirizine or levocetirizine with alcohol or other CNS depressants should generally be avoided if possible. In the event that they are used together, patients should be counseled against driving, operating machinery, or engaging in potentially hazardous activities requiring mental alertness and motor coordination.
References
Alternative for Tramadol N02A
Naloxone
Dextropropoxyphene
Naltrexone
Alternative for Cetirizine R06A
Diphenhydramine (topical)
Azelastine (ophthalmic)
Ketotifen
Azelastine
Acrivastine

Potential Metabolism Interactions

Substrate-Substrate Interaction：If more than one drug is metabolized by the same CYP, it is possible that its metabolism is inhibited because of the competition between the drugs. That means, it can be useful to lower the dosage of the drugs in the drug-cocktail because they remain longer in the organism than in monotherapy.
Inhibitor-Inhibitor Interaction：Combining two or more inhibitors of one CYP, should be compensated by lowering the dosage of these drugs because the metabolism is reduced and the drugs remain longer in the organism than in monotherapy. Not adapting the dosage bears the risk of even more side effects.
Inhibitor-Substrate Interaction：Combining drugs that have inhibitory effect and are substrates of one particular CYP, should be compensated by lowering the dosage. They rest longer in the organism than in monotherapy. Not adapting the dosage bears the risk of even more side effects.