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Lactic Acid, Citric Acid, and Potassium Bitartrate (Phexxi) Vaginal Gel for Contraception

 

Am Fam Physician. 2021 May 15;103(10):628-629.

Lactic acid, citric acid, and potassium bitartrate (Phexxi) is a vaginal gel labeled for use by women as an on-demand contraception. The gel maintains vaginal pH at its physiologic acidity, creating an environment inhospitable to sperm that inhibits sperm motility.

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DrugStarting doseDose formCost*

Lactic acid, citric acid, and potassium bitartrate (Phexxi)

Insert 5 g vaginally immediately before or up to one hour before sexual intercourse

Vaginal gel: lactic acid 1.8%, citric acid 1%, potassium bitartrate 0.4%

$285


*—Estimated lowest GoodRx price for one box of 12 prefilled applicators based on information obtained at http://www.goodrx.com (accessed March 31, 2021; zip code: 66211).

DrugStarting doseDose formCost*

Lactic acid, citric acid, and potassium bitartrate (Phexxi)

Insert 5 g vaginally immediately before or up to one hour before sexual intercourse

Vaginal gel: lactic acid 1.8%, citric acid 1%, potassium bitartrate 0.4%

$285


*—Estimated lowest GoodRx price for one box of 12 prefilled applicators based on information obtained at http://www.goodrx.com (accessed March 31, 2021; zip code: 66211).

Safety

Phexxi is considered to be a safe contraceptive option. In two trials of 4,773 women, approximately 1% of patients experienced adverse effects, but none of the effects were shown to be caused by Phexxi.1,2 Systemic exposure to the active ingredients in the gel is minimal and is not expected to lead to safety concerns. Phexxi is not absorbed and will not cause systemic effects.3 The manufacturer recommends that Phexxi be avoided in patients with a history of recurrent urinary tract infections or urinary tract abnormalities. The water-based gel does not interact with other vaginal products like miconazole, metronidazole (Metrogel), and tioconazole.3 Phexxi is safe to use in conjunction with hormonal contraceptives, latex, polyurethane, polyisoprene condoms, and vaginal diaphragms. It should not be used with vaginal rings.3 Phexxi can be used after childbirth as soon as it is safe to resume vaginal intercourse.

Tolerability

The most common adverse effects of Phexxi are localized to the vagina and include burning sensation (18%), itching (14.5%), vulvovaginal mycotic infection (9.1%), urinary tract infection (9%), bacterial vaginosis (8.1%), and vaginal discharge (5.5%).3 More than 45% of study participants experienced at least one adverse effect, but the majority were deemed mild to moderate in severity, and only 2% to 3% of study participants dropped out because of adverse effects.1,2 These rates and types of adverse effects are similar to those that occur with nonoxynol-9, the ingredient in over-the-counter spermicidal products.2 Male partners may also experience mild reactions such as itching, burning, and pain (9.8%).3

Effectiveness

Two studies have evaluated contraceptive effectiveness over an average of six months of use. In a case series of 1,330 women 18 to 35 years of age, 13.7% of women became pregnant during six months of use.1 In an unpublished randomized controlled trial of 3,324 women 18 to 35 years of age comparing Phexxi with the spermicide nonoxynol-9, Phexxi demonstrated an 89.5% pregnancy prevention rate with typical use and 95.9% with ideal use over six months, similar to the rates with nonoxynol-9 (90.0% and 95.8%, respectively).2 Although there are no data regarding 12-month effectiveness of Phexxi, the six-month typical-use rates would likely be comparable to other on-demand methods such as condoms (87% pregnancy prevention rate with typical use over 12 months). However, pregnancy prevention rates with Phexxi are lower than with oral contraceptives (92%) and intrauterine devices or progestin implants (greater than 99%).4  Table 1 compares first-year pregnancy prevention rates of various contraceptive methods with typical and ideal use.2,4

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TABLE 1.

First-Year Pregnancy Prevention Rates of Various Contraceptive Methods

MethodTypical useIdeal use

Progestin implant (12-month data)

99.9%

99.9%

Progestin intrauterine device (12-month data)

99.8%

99.8%

Combined oral contraceptives (12-month data)

92%

99.7%

Male condom (12-month data)

87%

98%

Withdrawal (12-month data)

80%

96%

Nonoxynol-9 spermicide (12-month

Author disclosure: No relevant financial affiliations.

Address correspondence to Joshua Steinberg, MD, at jds91md@gmail.com. Reprints are not available from the authors.

References

show all references

1. Thomas MA, Chappell BT, Maximos B, et al. A novel vaginal pH regulator: results from the phase 3 AMPOWER contraception clinical trial. Contracept X. 2020;2:100031....

2. ClinicalTrials.gov. U.S. National Library of Medicine. Identifier: NCT01306331. Study of contraceptive efficacy and safety of Phexxi (previously known as Amphora) gel compared to Conceptrol vaginal gel. Accessed November 8, 2020. https://clinicaltrials.gov/ct2/show/NCT01306331

3. DailyMed. Drug label information. Phexxi—lactic acid, l-, citric acid monohydrate, and potassium bitartrate gel. Accessed November 30, 2020. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=173ff411-7227-47b0-94dc-844e1ebaf14e

4. Trussell J, Aiken ARA. Contraceptive efficacy. In: Hatcher RA, et al., eds. Contraceptive Technology. 21st ed. Ayer Company Publishers; 2018.

5. VCF Contraceptive Gel Pre-filled Applicators - 10ct. Target. Accessed November 29, 2020. https://www.target.com/p/vcf-contraceptive-gel-pre-filled-applicators-10ct/-/A-16733458

STEPS new drug reviews cover Safety, Tolerability, Effectiveness, Price, and Simplicity. Each independent review is provided by authors who have no financial association with the drug manufacturer.

The series coordinator for AFP is Allen F. Shaughnessy, PharmD, MMedED, assistant medical editor.

A collection of STEPS published in AFP is available at https://www.aafp.org/afp/steps.

 

 

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