Drug interactions
Levonorgestrel oral / ethinylestradiol / ferrous bisglycinate + Tizanidine
Severity: Moderate
Levonorgestrel oral / ethinylestradiol / ferrous bisglycinate and Tizanidine: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Oral contraceptives reduce tizanidine clearance, with ethinylestradiol considered the main contributor. Tizanidine levels can rise substantially, increasing hypotension, drowsiness and bradycardia.
What this interaction means in plain words
Levonorgestrel oral / ethinylestradiol / ferrous bisglycinate and Tizanidine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Why it happens
Ethinylestradiol inhibits CYP1A2, reducing tizanidine metabolism.
What to do
Start tizanidine at a low dose and titrate carefully in women using combined oral contraceptives. Monitor blood pressure and sedation, and reduce the dose if adverse effects occur.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Tizanidine
- Ciprofloxacin + Tizanidine Contraindicated
- Fluvoxamine + Tizanidine Contraindicated
- Pefloxacin + Tizanidine Contraindicated
- Pipemidic acid + Tizanidine Contraindicated
- Benzhydrocodone / acetaminophen + Tizanidine Major
- Brexanolone + Tizanidine Major
Frequently asked questions
Can I take Levonorgestrel oral / ethinylestradiol / ferrous bisglycinate with Tizanidine?
MediHelp rates the interaction as moderate. Levonorgestrel oral / ethinylestradiol / ferrous bisglycinate and Tizanidine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Oral contraceptives reduce tizanidine clearance, with ethinylestradiol considered the main contributor. Tizanidine levels can rise substantially, increasing hypotension, drowsiness and bradycardia.
How serious is the interaction between Levonorgestrel oral / ethinylestradiol / ferrous bisglycinate and Tizanidine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Start tizanidine at a low dose and titrate carefully in women using combined oral contraceptives. Monitor blood pressure and sedation, and reduce the dose if adverse effects occur.
What other medicines interact with Tizanidine?
MediHelp also lists interactions of Tizanidine with, for example, Ciprofloxacin, Fluvoxamine, Pefloxacin. The full list is on the Tizanidine page.
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