Psoriasis
Clears moderate to severe plaques.
Methotrexate vs Protopic
Methotrexate: An old, inexpensive tablet or injection for severe psoriasis and psoriatic arthritis. It is taken once a week, not daily, and it needs regular blood tests. Protopic: A non-steroid ointment for eczema, used where steroids are hardest to keep using: the face, the eyelids, and skin folds. It carries a boxed warning that twenty years of follow-up have not supported.
Which one is right for you?
Choose Methotrexate if…
Choose for severe psoriasis, especially with joint pain, as an inexpensive weekly treatment with regular blood tests.
- Psoriasis with psoriatic arthritis
- Cost matters and biologics aren't covered
- You can avoid alcohol and keep up blood tests
Choose Protopic if…
Choose for eczema where steroids are hardest to keep using — face, eyelids, folds — or to prevent flares twice a week.
- Eczema on the face or eyelids
- You need repeated or long-term treatment
- Vitiligo on the face
Fine together
Can you take them together?
Protopic can be used on the face or folds while taking methotrexate. Very little Protopic reaches the blood.
At a glance
● Methotrexate
● Protopic
Type
Oral or injected immune suppressant
Topical calcineurin inhibitor (tacrolimus)
What it does
Calms overactive immune cells and skin-cell growth
Calms the immune reaction without thinning skin
Best for
Severe psoriasis and psoriatic arthritis
Eczema on the face, eyelids and folds
Prescription
Yes
Yes
Form
Tablet or injection
Ointment, 0.03% or 0.1%
How often
Once a week — never daily
Twice daily; twice weekly to prevent flares
Course length
Ongoing
Flares, then maintenance
Time to results
4–12 weeks
1–3 weeks
Main side effect
Nausea and tiredness the day after
Burning or warmth at first
Blood tests
Required
None
Pregnancy
Never
Check with your clinician
Cost
Low; generic available
Moderate; generic available
What it treats
Compare uses by strength of evidence. Evidence level describes confidence in a benefit, not its size.
Evidence level
Methotrexate
Protopic
Strong evidenceMost established uses
Eczema
Treats and prevents flares.
Moderate evidenceSome supportive research
Psoriatic Arthritis
Reduces joint symptoms.
Eczema
An option for severe eczema.
Vitiligo
Restores color, especially on the face.
Seborrheic Dermatitis
A steroid-free option for the face.
Limited evidenceEarly or small studies
—
Perioral Dermatitis
Can help steroid-induced cases.
Little evidence
Alopecia Areata
Mixed results in small studies.
Psoriasis
Too weak for body plaques, though useful in folds.
Not effective
Acne
No role in acne.
Acne
No role in acne.
How it works
Methotrexate
Diagram explanation and sources
Interferes with cell replication: Blocks folate-dependent processes used to make DNA. May increase adenosine signaling: This calming messenger can limit immune-cell activity. Reduces skin inflammation: Inflammatory activity and plaque buildup can decrease.
The psoriasis mechanism is not fully established. Folate antagonism affects replication, while low-dose anti-inflammatory actions include proposed adenosine pathways supported by experimental work; their precise clinical contributions are unresolved.
Protopic
Diagram explanation and sources
Inhibits calcineurin: Blocks a switch that helps activate T cells. Reduces immune messengers: T cells release fewer inflammation-driving signals. Calms eczema and itch: Redness and irritation ease as inflammation settles.
The drug binds FKBP-12 and inhibits calcineurin, reducing T-cell cytokine transcription; the complete atopic-dermatitis mechanism is not known. It also has other cellular effects.
How you take it
Treatment plan
This drug is taken once a week. Taking it every day can cause fatal bone marrow failure. Pick one day of the week, write it down, and keep to it.
Test dose: A single small dose, often 2.5 mg to 5 mg, with blood counts checked about a week later before going further. A safety check, not the treatment dose.
Starting dose: Commonly 7.5 mg to 15 mg once weekly, adjusted for age, weight, kidney function and other illnesses. Lower in older people and in reduced kidney function.
Going up: Small steps, usually 2.5 mg to 5 mg every few weeks with blood tests in between, until the psoriasis responds or side effects set the ceiling.
Usual dose: Most people settle between 15 mg and 25 mg once weekly. Above about 15 mg tablet absorption gets unreliable, a common point to switch to the injection.
Folic acid alongside it: It reduces nausea, mouth ulcers and blood count problems. Usually a daily dose on the days you are not taking methotrexate, or one larger weekly dose on a different day. It does not stop the drug working.
Total course: No fixed course. It continues as long as it works and blood tests stay normal, which for some people is years.
When to Apply: A thin layer twice a day to the affected skin, rubbed in gently. It goes on the rash, not over clear skin. Keep moisturizer a couple of hours apart — layering one straight onto the other has not been studied.
How to Start: Twice a day until the patch clears, usually one to three weeks, then stop. Many people then move to maintenance — twice a week on the places that always flare, even when they look normal. That is well supported and makes flares less frequent.
If It Irritates: Burning or stinging for fifteen to thirty minutes after applying is very common in the first days and is not an allergy. It settles within about a week. Keeping the tube in the fridge, applying to dry rather than damp skin, and skipping alcohol early on all help.
If It's Not Working: Check it is going on twice a day — two to three weeks is a fair trial. Then the options are the higher strength if you are an adult on 0.03%, a short steroid course to break the flare, or a look at whether infection or a contact allergy is driving the rash.
When to take it
Once a week, on the same day every week. Choose a day you will remember and write it somewhere visible. Some people take the whole dose at once; some split it into two portions about twelve hours apart on the same day to reduce nausea. Do not spread it across different days unless you were told to.
Take tablets with water, and with food if they upset your stomach. An evening dose means the tiredness and mild nausea happen while you are asleep.
Folic acid goes on the other days, as prescribed. It is not a substitute for a missed methotrexate dose.
With the weekly injection, keep to the same day and rotate the site.
Not covered in this guide yet
If you miss a dose
Take it as soon as you remember if it is within about two days of your usual day. If longer, skip it and take the next on your usual day. Never take two weekly doses close together to catch up, and never take a daily dose to make up for a missed week.
If you have taken more than one weekly dose, or taken it several days in a row, contact a doctor or a poison center straight away. Do not wait to see how you feel. This overdose is treatable caught early and dangerous when it is not.
Not covered in this guide yet
Monitoring
Methotrexate is watched by blood test, and the schedule is not optional. The problems it causes are silent until they are advanced.
Before starting: Full blood count, liver tests, kidney function, and a pregnancy test where relevant. Hepatitis B, hepatitis C, HIV and tuberculosis screening is standard, because the drug damps the immune system. A chest x-ray if there is any history of lung disease.
Early on: Blood counts and liver tests within a week or two of starting, and again after each dose increase. This is when a sudden drop in blood counts would show.
Once stable: Full blood count, liver tests and kidney function every one to three months, depending on the dose and what else you take, for as long as you are on the drug.
The liver over the long term: Years of methotrexate can scar the liver, and the risk rises with total lifetime dose, heavy alcohol use, obesity, diabetes and fatty liver disease. Biopsy used to be the check; most clinics now use a blood marker of scarring and a scan of liver stiffness.
The lungs: A rare but serious lung inflammation can occur. A new dry cough, breathlessness or fever means being seen, not waiting for the next appointment.
What to report between tests: Mouth ulcers, unexplained bruising or bleeding, sore throat or fever, dark urine, yellowing of the eyes or skin, severe nausea, any new cough or breathlessness.
No blood tests are needed. Blood levels are usually undetectable with the ointment and fall further as the barrier repairs — the opposite of the oral form used after transplants. Monitoring is a check at two to three weeks on whether the rash responded, then a plan for maintenance.
The boxed warning is the part to understand. It says long-term safety is not established, that rare cases of lymphoma and skin cancer were reported in people who used these drugs, and that continuous long-term use should be avoided. It was added in 2006, based mainly on animal studies using very high doses by mouth or injection, plus scattered case reports.
What has happened since matters. Large cohort studies, and a registry that followed treated children for a decade, have not found the rise in lymphoma the warning describes. Guidelines in the United States and Europe still recommend these drugs, including on the face and eyelids and as twice-weekly maintenance. The concern was theoretical, more than twenty years of use has not borne it out, and how long to continue is still a decision to make with a doctor.
Day-to-day monitoring is simple: keep skin checks routine, use sun protection on treated areas, and pause during a skin infection.
When you’ll see results
Approximate windows, not promises.
● Methotrexate
● Protopic
First dose
First doseTaking it: Once a week, not daily, with folic acid on the other days. Nausea, tiredness or mouth soreness in the day or two after each dose is common early on; folic acid usually blunts it.
Weeks 1 to 2
Weeks 1 to 2Settling in: Nothing visible in the skin yet.
Weeks 4 to 8
Weeks 4 to 8Working: Plaques thin and spread less, thickness and scale first. Joint pain from psoriatic arthritis often improves in the same window, one reason it is chosen over a skin-only treatment.
About 3 months
About 3 monthsJudge it here: Substantial improvement is the realistic target.
Beyond 3 months
Beyond 3 monthsLong term: Where it suits, the result holds while the dose continues, with regular blood tests. Some stay on it for years.
Many months
Many monthsNails: Nail psoriasis can improve, but slowly. Nails always lag behind the skin.
First few minutes
First few minutesApplying it: A thin layer twice a day. Burning or stinging for a short while afterward is common and worst in the first week.
Days 1 to 7
Days 1 to 7Adjusting: Burning is at its worst now. Itch often improves in the same week, which is what gets most people through.
Weeks 1 to 3
Weeks 1 to 3Working: Redness and thickening settle and the burning has usually stopped. Most people reach their best result here.
Maintenance
MaintenanceKeeping flares apart: Once clear, twice-weekly use on the trouble spots lengthens the gaps between flares. Licensed, not an improvisation.
Side effects
Sorted by what to do about them.
Methotrexate
Protopic
Common
Common
- Nausea or tiredness the day after the dose
- Mouth sores
- Mild hair thinning
Common
- Burning, warmth or itch in the first days
- Flushing with alcohol
Tell your doctor
Tell your doctor
- Cough or breathlessness
- Fever, sore throat or unusual bruising
Tell your doctor
- Skin infection or cold sores
Stop and get care
Stop and get care
- Taking it daily by mistake
- Yellowing skin or dark urine
Stop and get care
- Swollen glands that don't settle
Safety and who should avoid it
Pregnancy
Never
Both partners avoid conception during and for 3 months after.
Use care
Very little absorbed; ask your clinician.
Breastfeeding
Never
Not compatible.
Use care
Keep it off the nipple.
Children
Specialist only
Used in children with monitoring.
2 and older
0.03% from age 2.
Monitoring
Required
Blood counts, liver and kidney tests; every 3 months once stable.
None
—
Key interactions
Check
Trimethoprim-sulfamethoxazole, NSAIDs, some antibiotics; limit alcohol.
Check
Avoid light therapy and tanning.
Other cautions
Avoid
Liver disease, heavy drinking, kidney disease, active infection.
Avoid
Infected skin; weakened immune system.
Cost and getting it
Getting it and cost
Generic methotrexate tablets are among the least expensive systemic treatments in dermatology. Folic acid is cheap too.
The weekly auto-injector pens cost considerably more, and coverage usually requires showing that tablets caused nausea or did not work well enough. Plain injectable vials are cheaper than the pens.
The real cost is the monitoring, repeated blood tests and periodically a liver scan or blood marker. Usually covered, but they are appointments and not optional.
Insurers frequently require a trial of methotrexate before approving a biologic, one reason it is still so often the first systemic drug tried.
Both strengths come as generics, which brought the price down a long way, though it still costs more than a generic steroid ointment. Prices vary widely between pharmacies and discount cards sometimes beat insurance, so check more than one.
Prior authorization is still common, usually asking that a topical steroid was tried first. Tube size is the practical variable: twice-daily use means a small tube treating a child's face lasts far longer than the same tube on two hands.
When you stop
Comes back?
Psoriasis usually returns over months.
Eczema can return; twice-weekly use helps prevent it.
Taper needed?
Usually not, but plan the next step first.
No.
After the last dose
Wait at least 3 months before trying to conceive — applies to both partners.
No rebound and no thinning.
Common questions
Methotrexate:How often do I take it?
Once a week, on the same day. Never daily. Daily dosing by mistake is the most dangerous error with this drug and it has been fatal. Get medical help the same day if it happens.
Methotrexate:Why do I also have to take folic acid?
Methotrexate blocks folate, and the mouth ulcers, nausea and low blood counts come from that. Folic acid on the other days restores enough folate to reduce them without stopping the treatment working.
Methotrexate:Do I really need all the blood tests?
Yes. Liver damage and falling blood counts cause no symptoms until they are advanced. The tests are the only early warning.
Methotrexate:Can I drink alcohol?
The concern is regular drinking, not a single glass, because alcohol and methotrexate both stress the liver. Agree an actual limit with your doctor.
Methotrexate:Can I take it if I want to have a baby?
No. It must be stopped well before trying to conceive, and the advice covers both partners. It causes miscarriage and serious birth defects. Ask your own doctor how far in advance.
Methotrexate:How long before I know if it is working?
Give it about three months. First changes often show at four to eight weeks, but three months on a tolerated dose is the fair point to judge.
Methotrexate:Is it chemotherapy?
It is chemotherapy at much higher doses. At psoriasis doses it acts as an immune-calming drug, and the experience is not comparable.
Protopic:Is the cancer warning real?
Yes, and it is printed on the label — long-term safety is not established, and rare cases were reported. Studies following large groups for years have not found the increased risk. A caution, not a demonstrated harm.
Protopic:Why does it burn?
It acts on nerve endings in inflamed skin as well as on immune cells. Burning is worst in the first few days and gone within a week as the rash heals.
Protopic:Can I use it on my eyelids?
Yes — eyelid eczema is one of the main reasons it gets prescribed. Keep it off the eye itself and the lid margin.
Protopic:Why did my face go red after a glass of wine?
Alcohol flushing is a known effect while using it. Harmless, and it stops when the treatment does.
Protopic:Can I use it indefinitely?
The label asks for the shortest suitable use and for breaks. Twice-weekly maintenance on trouble spots is licensed and widely used. Make that decision with a doctor rather than leaving a prescription running.
Protopic:Do I need blood tests?
No. Blood levels are usually undetectable with the ointment. The tablets are a different treatment entirely.
Keep exploring.
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Protopic
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Methotrexate
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