Skip to Content

Drug interactions between acetaminophen / butalbital and Plan B One-Step

Results for the following 2 drugs:
acetaminophen/butalbital
Plan B One-Step (levonorgestrel)

Interactions between your drugs

Moderate

levonorgestrel butalbital

Applies to: Plan B One-Step (levonorgestrel) and acetaminophen / butalbital

Butalbital may decrease the effectiveness of levonorgestrel. If you are using low-dose contraceptives, there is an increased risk of breakthrough bleeding and unintended pregnancy during combined therapy with butalbital. Alternative or additional methods of birth control should be used while taking butalbital. If you take hormone replacement for menopause, notify your doctor if you have decreased efficacy of your hormones. You may notice symptoms of increased hot flashes, vaginal dryness or menstrual abnormalities. It is important that you tell your healthcare provider about all other medications that you are using including vitamins and herbs. Do not stop using your medications without first talking to your doctor first.

Switch to professional interaction data

Drug and food interactions

Moderate

levonorgestrel food

Applies to: Plan B One-Step (levonorgestrel)

Consumer information for this interaction is not currently available.

MONITOR: Grapefruit juice may increase the plasma concentrations of orally administered drugs that are substrates of the CYP450 3A4 isoenzyme. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. Because grapefruit juice inhibits primarily intestinal rather than hepatic CYP450 3A4, the magnitude of interaction is greatest for those drugs that undergo significant presystemic metabolism by CYP450 3A4 (i.e., drugs with low oral bioavailability). In general, the effect of grapefruit juice is concentration-, dose- and preparation-dependent, and can vary widely among brands. Certain preparations of grapefruit juice (e.g., high dose, double strength) have sometimes demonstrated potent inhibition of CYP450 3A4, while other preparations (e.g., low dose, single strength) have typically demonstrated moderate inhibition. Pharmacokinetic interactions involving grapefruit juice are also subject to a high degree of interpatient variability, thus the extent to which a given patient may be affected is difficult to predict.

MANAGEMENT: Patients who regularly consume grapefruit or grapefruit juice should be monitored for adverse effects and altered plasma concentrations of drugs that undergo significant presystemic metabolism by CYP450 3A4. Grapefruit and grapefruit juice should be avoided if an interaction is suspected. Orange juice is not expected to interact with these drugs.

Therapeutic duplication warnings

No therapeutic duplications were found for your selected drugs.

Drug Interaction Classification

The classifications below are a guideline only. The relevance of a particular drug interaction to a specific patient is difficult to determine using this tool alone given the large number of variables that may apply.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No information available.

Do not stop taking any medications without consulting your healthcare provider.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Hide