Lamotrigine side effects: vagina, bladder and the pill

Author: Jessica Lloyd
Senior Vulvovaginal Specialist Naturopath | BHSc(N) | ISSVD, ISSWSH, BSSM, ATMS

Last reviewed: July 20, 2026

Lamotrigine is a medication used to help manage epileptic seizures and bipolar disorder¹. Most people take it without much drama, but a small group notice something odd going on downstairs. Side effects of lamotrigine may include reproductive, vaginal and urinary tract symptoms and are reported to occur in about four per cent of those taking the drug.²

It is unclear why this happens, but when the person stops taking lamotrigine, the issues disappear. When the drug is reintroduced, symptoms return.² That stop-start pattern is the clearest sign the pills are behind it, rather than a coincidental thrush or urinary tract infection.

How lamotrigine affects your vagina, urinary tract and hormones

The honest answer is that nobody has pinned down a mechanism for the vaginal and urinary symptoms. The best evidence is a single published case report of a woman whose vaginitis and painful weeing cleared when she stopped lamotrigine and came back when she restarted it.² That is a strong pattern in one person, not proof of how it happens in everyone, so treat it as a signal to watch for rather than a certainty.

If you develop vaginal soreness, itching or burning while weeing on lamotrigine, it is still worth having the usual suspects ruled out first, because thrush, bacterial vaginosis and a urinary tract infection are far more common and each has its own treatment. A swab and a urine dip cost you nothing and can save you weeks of guessing. If everything comes back clear and the timing lines up with your pills, that is when the drug moves up the list.

The contraceptive interaction that can catch you out

This is the part that matters most for anyone who could get pregnant. Lamotrigine and the combined hormonal pill push each other around, in both directions.

The oestrogen in a combined pill speeds up the way your liver clears lamotrigine. In a study of healthy women, adding a combined oral contraceptive roughly doubled lamotrigine clearance, which drops your blood levels and can let seizures or mood symptoms break through.⁵ Levels also swing back up during the pill-free week, so the seesaw is real. This is why doctors often adjust the lamotrigine dose around the pill, and why you should never change either one on your own.

Going the other way, lamotrigine nudges your contraceptive too. In the same study the amount of levonorgestrel (the progestogen) in the blood fell by 19 per cent, and hormone measurements showed some loss of the pill’s usual grip on the ovaries.⁵ Nearly a third of the women had breakthrough bleeding.⁵ On its own that 19 per cent dip is not thought to reliably cause ovulation, but it is a reminder that the pill’s margin is thinner than you might assume, and unexpected spotting is worth mentioning rather than ignoring. If a reliable pregnancy plan matters to you, talk to your prescriber about whether a method that does not tangle with lamotrigine, such as an intrauterine device, suits you better. Our contraception guide runs through the options.

Urogenital and reproductive side effects of lamotrigine³

Vaginitis (vaginal inflammation)
Painful, sore or itchy vagina
Painful periods
Changes to the menstrual cycle
Changes to sexual desire, including an increase
Urinary frequency
Burning or pain during urination

Other reported side effects³

One deserves its own flag: skin rash. Most rashes on lamotrigine are mild, but a small number turn serious, including Stevens-Johnson syndrome, a medical emergency. In the six-month safety trial, three rashes were judged serious and one was Stevens-Johnson syndrome that put the person in hospital; all cleared once the drug was stopped.³ A rash with blistering, peeling, fever or facial swelling means stop and seek urgent care the same day.

Headache
Dizziness
Blurred or double vision
Lack of coordination
Sleepiness
Nausea
Vomiting
Insomnia, oversleeping
Tremor
Rash
Fever
Abdominal pain
Back pain
Fatigue
Dry mouth
Allergic reaction
Skin rashes with blistering, peeling, redness
Bloody stools, stomach upset, bloating
Chest pain
Extreme weakness, dizziness or fainting
Swollen glands
Suicidal ideation
Aches, joint pain
Eye twitches
Moodiness
Appetite changes, weight loss
Nose bleeds
Runny, stuffy nose
Swelling of hands, feet, ankles, face

How does lamotrigine work?

Researchers are still not exactly sure how lamotrigine works. This makes it tricky to work out how exactly it could cause vaginal and urinary tract symptoms.

We do know lamotrigine binds to and inhibits voltage-gated sodium channels, which in turn stabilises presynaptic neuronal membranes and inhibits presynaptic glutamate and aspartate release. It is not believed that lamotrigine has significant effects on other neurotransmitters (serotonin, norepinephrine, dopamine).⁴

A theory put forward suggests lamotrigine may interact with voltage-activated calcium-gated channels, which in turn may have broad impacts. Lamotrigine inhibits dihydrofolate reductase, which may indicate teratogenicity. Lamotrigine has a half-life of about 29 hours.

Frequently asked questions

Can lamotrigine cause vaginitis or thrush-like symptoms?

It can, though it is not common. Vaginitis and painful urination are listed among lamotrigine’s urogenital side effects, and there is a published case where the symptoms reliably came and went with the drug.²³ That said, most vaginal soreness and discharge has a more ordinary cause.

Before you pin it on the pills, get a swab and a urine test to rule out thrush, bacterial vaginosis and a urinary tract infection. If those are clear and the symptoms track your lamotrigine dose, raise it with your prescriber rather than stopping on your own.

Does lamotrigine stop the pill from working?

Lamotrigine lowers the level of the progestogen levonorgestrel in your blood by around 19 per cent and loosens the pill’s suppression of the ovaries a little, with breakthrough bleeding reported in nearly a third of women in one study.⁵ On its own that is not thought to reliably cause a pregnancy, but it does thin the safety margin.

The bigger issue runs the other way: the oestrogen in a combined pill roughly doubles how fast you clear lamotrigine, so your seizure or mood control can slip, and your levels lurch during the pill-free week.⁵ Because both drugs affect each other, any change to either should be planned with your doctor.

Should I stop lamotrigine if I get these symptoms?

Not without medical advice. Stopping an anti-seizure or mood-stabilising drug suddenly can be risky, and the urogenital symptoms, while annoying, are not usually dangerous. Book in with your prescriber and describe the timing.

One exception is a serious skin reaction. A rash with blistering, peeling skin, mouth or eye sores, fever or facial swelling can signal Stevens-Johnson syndrome, which is an emergency.³ If that happens, stop the drug and seek urgent care the same day.

This article is for general information and is not a substitute for individual medical advice. Lamotrigine is a prescription medicine, and decisions about your dose, your contraception and any side effects should be made with your prescriber or pharmacist, who knows your full history. If you have a severe rash, trouble breathing, thoughts of harming yourself or another medical emergency, seek urgent care straight away.