Fluvoxamine Drastically Increases Concentrations and Effects of Tizanidine: A Potentially Hazardous Interaction

@article{Granfors2004FluvoxamineDI,
  title={Fluvoxamine Drastically Increases Concentrations and Effects of Tizanidine: A Potentially Hazardous Interaction},
  author={Marika T. Granfors and Janne T. Backman and Mikko Neuvonen and Jouni Ahonen and Pertti J. Neuvonen},
  journal={Clinical Pharmacology \& Therapeutics},
  year={2004},
  volume={75}
}

A clinically relevant review of tizanidine hydrochloride dose relationships to pharmacokinetics, drug safety and effectiveness in healthy subjects and patients

Aims:  Tizanidine, one of the few oral antispastic therapies approved for use in the USA, has a narrow therapeutic index that can often make optimal patient dosing difficult. We surveyed the

Tobacco smoking and its drug interactions with comedications involving CYP and UGT enzymes and nicotine

  • N. Maideen
  • Medicine
    World Journal of Pharmacology
  • 2019
Tobacco smoking and its drug interactions with comedications involving CYP and UGT enzymes and nicotine

Rofecoxib is a potent inhibitor of cytochrome P450 1A2: studies with tizanidine and caffeine in healthy subjects.

Rofecoxib is a potent inhibitor of CYP1A2 and it greatly increases the plasma concentrations and adverse effects of tizanidine, raising concerns about interactions between rofecoxIB and other CYP 1A2 substrate and inhibitor drugs.

Drug metabolism and drug transport of the 100 most prescribed oral drugs

This work identified the 100 most prescribed drugs in six countries and conducted a literature search on in vitro data to assess contribution of Phase I and II enzymes and drug transporters to metabolism and transport.

Rifampicin is only a weak inducer of CYP1A2-mediated presystemic and systemic metabolism: studies with tizanidine and caffeine

The inducibility of CYP1A2-mediated presystemic (tizanidine, caffeine) and systemic metabolism by rifampicin is weak at the most, compared to CYP3A4 substrate drugs, which are much less susceptible to drug interactions caused by enzyme inducers of the rifampsicin type.

Co‐Prescription of Strong CYP1A2 Inhibitors and the Risk of Tizanidine‐Associated Hypotension: A Retrospective Cohort Study

CYP1A2 inhibition increases the risk of hypotensive episodes associated with the use of tizanidine in routine clinical practice, and a sensitivity analysis that defined hypotension as SBP < 90 mmHg also yielded higher rates of hypotension among patients prescribed tIZanidine.

Effects of Mexiletine, a CYP1A2 Inhibitor, on Tizanidine Pharmacokinetics and Pharmacodynamics

It is suggested that coadministration of mexiletine increased blood tizanidine concentrations and enhanced tIZanidine pharmacodynamics in terms of reduction in blood pressure and adverse symptoms.
...

References

SHOWING 1-10 OF 30 REFERENCES

Effects of fluconazole and fluvoxamine on the pharmacokinetics and pharmacodynamics of glimepiride

Our objective was to study the effects of fluconazole and fluvoxamine on the pharmacokinetics and pharmacodynamics of glimepiride, a new sulfonylurea antidiabetic drug.

Low daily 10‐mg and 20‐mg doses of fluvoxamine inhibit the metabolism of both caffeine (cytochrome P4501A2) and omeprazole (cytochrome P4502C19)

Whether nontherapeutic doses of fluvoxamine inhibit CYP1A2 but possibly not CYP2C19 is investigated.

The effect of fluvoxamine on the pharmacokinetics and pharmacodynamics of buspirone

Fluvoxamine moderately increased plasma buspirone concentrations and decreased the production of the active 1-PP metabolite of buspir one, and this pharmacokinetic interaction was not associated with impairment of psychomotor performance and it is probably of limited clinical significance.

The Effect of Erythromycin, Fluvoxamine, and Their Combination on the Pharmacokinetics of Ropivacaine

It is concluded that inhibition of CYP1A2 by fluvoxamine considerably reduces elimination of ropivacaine, and concomitant use of flu voxamine and CYP3A4 inhibitor erythromycin further increases plasma ropvacaine concentration by decreasing its clearance.

Selegiline pharmacokinetics are unaffected by the CYP3A4 inhibitor itraconazole

The findings suggest that selegiline is not susceptible to interaction with CYP3A4 inhibitors, and shows no inhibitory effect on the biotransformation of se LEGiline to desmethylselegilines and l-methamphetamine by human liver microsomes.

Tizanidine is mainly metabolized by cytochrome p450 1A2 in vitro.

CYP1A2 is primarily responsible for the metabolism of tizanidine, but other recombinant CYPs had little metabolic capacity for the drug and CYP1A1 inhibitors may inhibit its metabolism also in vivo.

An Evaluation of the Dose‐Dependent Inhibition of CYP1A2 by Rofecoxib Using Theophylline as a CYP1A2 Probe

All three commercially marketed doses of rofecoxib were found to slow the clearance of theophylline with no detectable effect on absorption as well as point estimates of CL/F found to be in agreement with those derived from AUC.