Drug Interactions between amoxicillin / clarithromycin / vonoprazan and quinestrol

Clarithromycin may increase the blood levels and effects of quinestrol. You may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications. Contact your doctor if your condition changes or you experience increased side effects, such as changes in weight and/or appetite, dizziness, headaches, upset stomach, nausea, vomiting, bloating, and/or bleeding between menstrual cycles. Seek immediate medical care if you experience any of the following, as they could indicate that you are experiencing a serious side effect: dark urine; light-colored stools; yellow skin or eyes; very bad headache or dizziness; passing out; change in eyesight or a change in how contact lenses feel; severe upset stomach; severe vomiting; pain in the upper right belly area, right shoulder area, or between the shoulder blades; chest pain or pressure; coughing up blood; trouble breathing; swelling, warmth, numbness, change of color or pain in a leg or arm; trouble speaking or swallowing; depression or other mood changes; a lump in the breast; breast pain or soreness; nipple discharge; bone pain; and/or muscle cramps or spasms.

On the other hand, antibiotics such as clarithromycin can also reduce the amount of estrogen available in the body from estrogen containing hormonal medications. If you are using an estrogen containing medication for birth control, you may be at increased risk for pregnancy or breakthrough bleeding. Be sure to alert your doctor if you are having any vomiting and/or diarrhea as this too can impact how well your hormonal birth control works. Talk to your doctor or pharmacist to determine if you should use an alternative or additional form of birth control during or after treatment with clarithromycin. If you are using an estrogen containing medication for a purpose other than birth control, discuss any questions you may have or any changes you notice regarding how well your medication is working with your doctor. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Consumer information for this interaction is not currently available.

MONITOR: The effectiveness of estrogen-containing medications may be impaired by concomitant treatment with antimicrobial agents. During metabolism, the estrogen component is conjugated, resulting in sulfation or glucuronidation of the original estrogenic steroid. The conjugates reach the intestine by way of the bile duct where hydrolytic enzymes of intestinal bacteria break down the conjugates into free, active estrogenic hormone. The active hormone is then available for enterohepatic cycling, which helps to maintain estrogen levels. It is important to note that the progestin component of a combined hormonal product does not undergo this process. It has been suggested that broad-spectrum antibiotics may reduce the effectiveness of estrogen-containing contraceptives because of their potential to reduce the number of intestinal bacteria and thus interfere with enterohepatic cycling of estrogen. Most of the research regarding this possible interaction has been done with oral contraceptives, but all estrogens appear to undergo enterohepatic recirculation so theoretically this interaction is a possibility with estrogen containing medications that are being used for alternative purposes. However, the risk appears to be small, and supportive data are primarily limited to anecdotal evidence from case reports and findings from uncontrolled or poorly controlled studies. Most antimicrobials, with the exception of enzyme inducing medications like the rifamycins and possibly griseofulvin, have not been shown to significantly increase the clearance of oral contraceptive estrogens. It is possible that a small number of women may be more sensitive to the effects of antimicrobials on estrogen disposition in vivo, but risk factors or genetic predispositions have yet to be identified.

MANAGEMENT: If a person is using estrogen for a purpose other than contraception, it is important to note that there is a theoretical possibility of lower levels of systemic estrogen available during treatment with an antibiotic due to interference with enterohepatic cycling. These patients should be counseled to report any changes in efficacy of the hormonal product to their healthcare provider. In the case of contraception specifically, the Centers for Disease Control and Prevention do not consider most broad-spectrum antibiotics to significantly interfere with the effectiveness of combined hormonal contraception. However, the manufacturers of certain combined hormonal contraceptives and/or certain antibiotics do recommend using a back-up method of birth control for varying amounts of time; therefore, consulting the product labeling of each medication involved is advised. Some illnesses, as well as some antibiotics, may cause nausea, vomiting, and/or diarrhea. If the patient vomits within a few hours of taking an oral contraceptive pill, consult the product labeling for instructions on what to do in the event of a missed pill. Some authorities recommend a back-up method of birth control if an individual has persistent vomiting or diarrhea.

Information for this minor interaction is available on the professional version.