Ticlopidine Theophylline

Colli A, Buccino G, Cocciolo M, Parravicini R, Elli GM, Scaltrini G. Ticlopidine-theophylline interaction. ClinPhannacol Ther ( 9S1) 41, 358-62. 

CYP1A2 15 -5 Fluvoxamine Caffeine Cyclobenzaprine Theophylline Thiothixene Olanzapine Ciprofloxacin Fluvoxamine Ticlopidine Halogenated biphenyls Polycyclic aromatic Hydrocarbons Omeprazole Rosiglitazone Phenylisothiocyanate... 

A study in 10 healthy subjects found that ticlopidine 250 mg twice daily for 3 weeks decreased the clearance of phenazone (a marker of enzyme inhibition or induction). The AUC increased by 14% and the half-life increased by 27%, suggesting that ticlopidine has some mild enzyme-inhibiting effects. This is consistent with the way ticlopidine appears to inhibit the metabolism of theophylline , (p.ll77), but so far no other drugs seem to be affected to a clinically important extent. 

Ticlopidine reduces the clearance of theophylline and is expected to raise its serum levels. Clopidogrel, an analogue of ticlopidine, appears not to interact. 

In 10 healthy subjects ticlopidine 250 mg twice daily for 10 days reduced the clearance of a single 5-mg/kg oral dose of theophylline by 37% and increased the half-lifeby44%, from about 8.5 hours to 12 hours. The reason for these effects is not known but it seems possible that ticlopidine inhibits the metabolism of theophylline by the liver. Information is limited, but it would seem prudent to monitor the effects of concurrent use it may... 

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