How is ethinyl estradiol metabolized?
Ethinyl estradiol is excreted in the urine and feces as glucuronide and sulfate conjugates, and it undergoes enterohepatic recirculation. The terminal elimination half-life of ethinyl estradiol after a single dose of SeasoniqueTM was found to be about 18 hours.
Are oral contraceptives CYP3A4 inducers?
Conclusion. Levonorgestrel containing combination oral products and implants containing levonorgestrel or etonogestrel were prone to CYP3A4-inducing drug-drug interactions that may increase contraceptive failures.
What effect does cyp450 inhibitors or inducers have on oral contraceptives?
Oral contraceptive hormones (OCs) are metabolized by the hepatic cytochrome p450 system; thus, inducers of the p450 system may increase OC metabolism. Whether decreased OC levels, associated with p450 inducer exposure, increase the risk of pregnancy is widely suspected but remains unknown.
What drug is metabolized by CYP3A4?
Cytochrome P450 enzymes metabolize approximately 60% of prescribed drugs, with CYP3A4 responsible for about half of this metabolism; substrates include acetaminophen, codeine, ciclosporin (cyclosporin), diazepam, and erythromycin. The enzyme also metabolizes some steroids and carcinogens.
What are CYP3A4 inhibitors and inducers?
Potent inhibitors of CYP3A4 include clarithromycin, erythromycin, diltiazem, itraconazole, ketoconazole, ritonavir, verapamil, goldenseal and grapefruit. Inducers of CYP3A4 include phenobarbital, phenytoin, rifampicin, St. John’s Wort and glucocorticoids.
What is the difference between estradiol and ethinyl estradiol?
Ethinylestradiol (EE) is a synthetic form of estradiol commonly used as the estrogenic component of most combination oral contraceptive pills (OCPs). Ethinyl estradiol is different from estradiol due to its higher biovailability and increased resistance to metabolism, rendering it more suitable for oral administration.
What enzyme breaks down birth control?
OCs are the most common form of contraceptive used. Most OCs are metabolized by CYP3A enzymes and are subject to several drug interactions.
What happens if CYP3A4 is inhibited?
1-4 The inhibition of CYP3A4 can result in the accumulation of parent drug concentrations that can put the patient at increased risk for side effects and possible toxicity.
What is the difference between CYP3A4 and CYP3A?
CYP3A4 is the most abundantly expressed CYP and accounts for approximately 30 to 40% of the total CYPcontent in human adult liver and small intestine. CYP3A5 is 83% homologous to CYP3A4, is expressed at a much lower level than CYP3A4 in the liver, but is the main CYP3A isoform in the kidney.
How many drugs does CYP3A4 metabolize?
CYP3A4 metabolizes more than 1900 drugs: 1033 act as substrates (897 major, 136 minor); 696, as inhibitors (118 weak, 437 moderate, and 141 strong); and 241, as inducers of the CYP3A4 enzyme [113].
What drugs are strong CYP3A4 inducers?
Inducers of CYP3A4 include phenobarbital, phenytoin, rifampicin, St. John’s Wort and glucocorticoids.
What is the half-life of ethinyl estradiol?
The mean elimination half-life of ethinyl estradiol was approximately 12 hours for both chronic and acute OC use, although there was a nonsignificant tendency for lower ethinyl estradiol clearances in chronic OC users.
How does ethinyl estradiol work?
Levonorgestrel and ethinyl estradiol combination is used to prevent pregnancy. It works by stopping a woman’s egg from fully developing each month. The egg can no longer accept a sperm and fertilization (pregnancy) is prevented. No contraceptive method is 100 percent effective.
Why does grapefruit affect birth control?
Grapefruit contains compounds known as furanocoumarins that block (inhibit) these enzymes responsible for breaking down estrogens. When grapefruit and the pill are consumed, blood levels of estrogen may rise, resulting in a risk for new or worsened side effects.
How does grapefruit affect the pill?
Grapefruit’s culprit chemical does not interact directly with your pills. Instead, it binds to an enzyme in your intestinal tract known as CYP3A4, which reduces the absorption of certain medications. When grapefruit juice blocks the enzyme, it’s easier for the medication to pass from your gut to your bloodstream.
What drugs are strong CYP3A4 inhibitors?
What is the role of CYP3A4?
CYP3A4 is a major cytochrome P450. It catalyses a broad range of substrates including xenobiotics such as clinically used drugs and endogenous compounds bile acids. Its function to detoxify bile acids could be used for treating cholestasis, which is a condition characterised by accumulation of bile acids.
What drugs are CYP2D6 inhibitors?
| Strong inhibitors | Moderate inhibitors | |
|---|---|---|
| CYP2C19 | fluconazole(f), fluoxetine(g), fluvoxamine(a), ticlopidine(c) | cenobamate, felbamate, voriconazole(d) |
| CYP2D6 | bupropion, fluoxetine(g), paroxetine, quinidine(h), terbinafine | abiraterone, cinacalcet, duloxetine, lorcaserin, mirabegron, rolapitant |
What are CYP3A4 inducers?
CYP3A4 inducers are drugs that increase the activity of CYP3A4. Note that the CYP3A4 enzyme is particularly susceptible to enzyme inducers, and marked reductions in the plasma concentrations of CYP3A4 substrates may occur.
What are CYP3A4 inducers used for?
An antibiotic used to treat several types of mycobacterial infections including Mycobacterium avium complex, leprosy, and in combination with other antibacterials to treat latent or active tuberculosis.
How long does it take ethinyl estradiol to leave your system?
Ethinylestradiol
| Clinical data | |
|---|---|
| Metabolism | Liver (primarily CYP3A4) |
| Metabolites | • Ethinylestradiol sulfate • Others |
| Elimination half-life | 7–36 hours |
| Excretion | Feces: 62% Urine: 38% |
How long does ethinyl estradiol stay in your system?
The pill and minipill: The hormones from the pill or minipill will leave your system 48 hours after the last pill was taken. Expect your menstrual cycles and ovulation to return to your “normal” within three months after stopping the pill.
What makes birth control pills less effective?
The main thing that makes the pill not work is not taking it every day. But other things, like vomiting or having diarrhea for more than 48 hours (2 days) may lower how well the pill prevents pregnancy. If you take any of these while you’re on the pill, use condoms as a backup method.
Do oranges affect birth control?
Does orange juice affect birth control? Still worried about how to get your vitamin C? Most other fruits like orange juice or cranberry juice are fine to eat or drink if you take birth control.
Can grapefruit cancel out birth control?
Taking your pill with grapefruit juice is unlikely to decrease the effectiveness of the oral contraceptive. Clinically relevant drug interactions with grapefruit juice can occur with other medicines, too, so always check with your doctor for the impact.