Midamor with the birth control pill
Many women of reproductive age take a combined or progestogen-only oral contraceptive while also using a chronic medication such as Midamor (Amiloride). The combination is generally fine at 5mg, but a small number of medications can reduce contraceptive efficacy meaningfully and need either a backup method or a switch.
How Midamor can affect contraceptive efficacy
Combined and progestogen-only contraceptives are metabolised through CYP3A4. Strong CYP3A4 inducers (some antiepileptics, rifampicin, St John's Wort) lower contraceptive plasma levels and reduce efficacy. Whether Amiloride acts on CYP3A4 determines whether Midamor affects contraception. Most agents in Diuretics have no clinically meaningful effect on the pill at 5mg.
Practical guidance
According to the prescribing information for Amiloride, women on hormonal contraception should review Midamor with the prescribing pharmacist or doctor. Where an interaction is documented, additional barrier contraception or switching to a non-oral method (IUD, implant) for the duration of Midamor therapy is the standard mitigation.
Frequently asked questions
Will Midamor make my pill less effective? ▾
Most Diuretics medications at 5mg do not affect oral contraceptive efficacy. The exceptions are CYP3A4-inducing drugs and a small number of others. The prescribing information for Amiloride states whether the interaction is meaningful.
Do I need a backup contraceptive on Midamor? ▾
Backup contraception is needed only when there is a documented interaction between Midamor and the contraceptive method. For most users at 5mg, no backup is required. The pharmacist confirms whether Amiloride interacts with hormonal contraception.
More on Midamor
- With alcoholMidamor and alcohol — is it safe to drink?
- With foodShould Midamor be taken with food?
- Side effectsMidamor side effects: common, rare and warning signs
- Dosage guideMidamor dosage guide: how much to take and when
- OnsetHow fast does Midamor start working?
- DurationHow long does Midamor last?
The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.