Pembrolizumab Injection
Pembrolizumab (Keytruda) is an immunotherapy injection that helps your immune system find and fight many types of cancer.
🧬 Where this information comes from Click to expand
The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 1 clinical label set within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →
📖 Pembrolizumab Injection: Patient Information Guide
A plain-language walkthrough of Pembrolizumab Injection — what it treats, how it works, how it’s taken, side effects, warnings and interactions. Tap any section to expand it.
🎯What it's used for▾
Pembrolizumab treats a wide range of cancers, either alone or with other therapies. Main uses include:
- Melanoma — advanced/unresectable disease, and as adjuvant (post-surgery) treatment for Stage IIB–III
- Non-small cell lung cancer (NSCLC) — first-line and later-line treatment; also before and after surgery for resectable disease
- Malignant pleural mesothelioma — advanced or metastatic, combined with chemotherapy
- Head and neck squamous cell cancer (HNSCC) — locally advanced or metastatic
- Bladder/urothelial cancer — advanced disease
- Certain colorectal, gastric, esophageal, cervical, and liver cancers
- Kidney cancer (RCC) — advanced or adjuvant after surgery
- Endometrial carcinoma, ovarian cancer, triple-negative breast cancer (TNBC)
- Blood cancers — classic Hodgkin lymphoma (cHL) and certain large B-cell lymphomas (PMBCL)
- Tumors with specific markers — MSI-H/dMMR (certain DNA repair defects), TMB-H (high tumor mutation burden), PD-L1-expressing tumors
- Merkel cell carcinoma (MCC) and cutaneous squamous cell carcinoma (cSCC)
⚙️How it works▾
Cancer cells can disguise themselves by activating a checkpoint called the PD-1 pathway — essentially putting up a "don't attack me" signal that quiets your immune system's T cells. Pembrolizumab is a monoclonal antibody (a precisely engineered protein) that locks onto the PD-1 receptor on T cells and blocks that signal. With the brake released, your T cells can recognize tumor cells as foreign and mount an attack against them.
In some cancer types, pembrolizumab is used alongside lenvatinib (another cancer drug). In lab models, that combination reduced certain immune-suppressing cells in tumors and boosted cancer-killing T cells more than either drug alone.
💊How it's taken▾
Pembrolizumab is given as a 30-minute IV infusion (drip through a vein) in a clinic or hospital infusion center — it is not a pill or home injection. It is typically administered every 3 weeks or every 6 weeks; your oncologist will determine the schedule that fits your treatment plan. For pediatric patients, dosing is based on body weight.
- No food or fasting requirements are tied to the infusion
- Your exact dose and schedule are set by your prescriber — follow that plan precisely
- If you miss an appointment, contact your care team to reschedule as soon as possible
🤒Side effects — in detail▾
The most commonly reported side effects include:
- Fatigue or weakness
- Nausea, diarrhea, or constipation
- Rash or itching
- Cough or shortness of breath
- Decreased appetite
- Fever
- Muscle and joint pain
- Underactive thyroid (hypothyroidism)
More serious immune-related reactions can affect your lungs, liver, bowel, kidneys, skin, and hormone glands — these need prompt medical attention. If you notice anything new or worsening, call your doctor right away rather than waiting for your next appointment.
⚠️Warnings & precautions▾
- Immune-mediated reactions: Because pembrolizumab activates your immune system, it can cause it to attack healthy organs — lungs (pneumonitis), bowel (colitis), liver (hepatitis), kidneys (nephritis), skin, thyroid, adrenal glands, and more. These can be severe or fatal and can occur at any time, even after treatment ends.
- Infusion reactions: Symptoms during or right after the IV infusion — such as chills, flushing, dizziness, or breathing difficulty — should be reported immediately to the infusion team.
- Stem cell transplant risks: Serious, potentially fatal complications can occur in patients who receive an allogeneic (donor) stem cell transplant before or after pembrolizumab treatment.
- Multiple myeloma caution: Combining pembrolizumab with thalidomide-type drugs plus steroids for multiple myeloma is not recommended outside clinical trials.
- Embryo-fetal toxicity: This drug can harm or cause loss of an unborn baby. Effective contraception is essential during treatment.
🔀What it interacts with▾
Pembrolizumab has a focused but serious interaction profile — always give your full medication list to your oncologist and pharmacist:
- Thalidomide analogues (e.g., lenalidomide, pomalidomide) + dexamethasone: Combining these with pembrolizumab for multiple myeloma carries serious risks and is not recommended outside carefully controlled clinical trials.
- Allogeneic stem cell transplant (HSCT): Having this type of bone marrow/stem cell transplant before or after pembrolizumab treatment raises the risk of severe, potentially fatal transplant complications — your team needs to know your full history.
This is not a complete list of interactions. Always talk with your doctor or pharmacist before starting, stopping, or changing any medication.
📋Before taking it▾
- Pregnancy: Pembrolizumab can harm a developing baby and may increase the risk of miscarriage or stillbirth. Tell your doctor immediately if you are or could be pregnant.
- Breastfeeding: Do not breastfeed during treatment or for 4 months after your last dose — the potential risk to the baby is unknown and considered serious.
- Contraception: Women of childbearing potential must use effective birth control during treatment.
- Autoimmune conditions: Tell your doctor if you have any autoimmune disease — activating the immune system could worsen these conditions.
- Prior stem cell transplant: Report any history of allogeneic (donor) bone marrow or stem cell transplant before starting treatment.
- Liver impairment: Severe liver impairment may affect how pembrolizumab behaves — discuss your liver health with your doctor.
- Children: Approved for pediatric patients (age 12+) for melanoma; some indications allow younger children. Weight-based dosing is used.
- Older adults: Age alone (up to 94 years studied) did not meaningfully change how the drug is processed in the body.
📡Pharmacodynamics — effects in the body▾
Pembrolizumab works by blocking the PD-1 checkpoint — a pathway cancer cells exploit to hide from immune attack. By releasing that inhibition, the drug restores the immune system's ability to detect and destroy tumor cells. Studies in adults with melanoma, Hodgkin lymphoma, and certain B-cell lymphomas have not identified a clear relationship between the amount of drug in the blood and either its effectiveness or its side effects across the doses studied.
🔬Pharmacokinetics — how your body processes it▾
Pembrolizumab is given directly into the bloodstream by IV, so there is no absorption step. It reaches stable, steady-state levels in the blood by about 16 weeks of regular dosing. The drug has a long half-life of approximately 22 days — meaning it stays active in your body for weeks after each dose. It is cleared slowly through normal protein breakdown pathways; age, sex, race, mild-to-moderate kidney impairment, and mild-to-moderate liver impairment do not significantly affect how the body handles it. Severe liver impairment has not been fully studied.
📦How to store it▾
Store vials under refrigeration at 2°C to 8°C (36°F to 46°F) in original carton to protect from light. Do not freeze.
📄 Written from Pembrolizumab Injection’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Every point is grounded in that labeling — nothing is invented. How we use AI →
Supplements & herbs that interact with Pembrolizumab Injection
1 supplement and herbal product has documented interactions with Pembrolizumab Injection in the licensed clinical database we use. Most are manageable — but your pharmacist should know about everything you take, including vitamins and herbals.
Educational information from a licensed clinical database (Natural Medicines) — see our data sources & update cadence. Not medical advice: an interaction being documented does not mean it will happen to you; do not start or stop medications or supplements without professional guidance.
🩺 Pharmacist Counseling Corner
Quick, plain-English answers to the questions patients ask most about Pembrolizumab Injection — the kind of thing our pharmacy team would talk through with you at the counter.
What exactly is pembrolizumab and how is it different from regular chemotherapy? ▾
How often will I need to come in for infusions, and how long does each one take? ▾
What side effects should I just manage at home versus which ones mean I need to call someone right away? ▾
Can I get pregnant or breastfeed while on this medication? ▾
I've heard that immunotherapy can attack your own body — is that true? How will my doctors watch for that? ▾
Does my tumor need to have a specific marker for this drug to work for me? ▾
Is Pembrolizumab Injection available over the counter? ▾
When was Pembrolizumab Injection first available? ▾
Who makes Pembrolizumab Injection? ▾
💬 Answers drafted from Pembrolizumab Injection’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Grounded in that labeling — nothing is made up. How we use AI →
🧰 Keep exploring
💊 How Pembrolizumab Injection comes
Pembrolizumab Injection is available in 1 form. Different forms and brands can have different approved uses, doses, schedules, and directions. Follow the instructions for your exact product, and do not switch forms without guidance from your prescriber or pharmacist.
Injection
📊 Pembrolizumab Injection across the U.S. market
How Pembrolizumab Injection appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.
Share of FDA-listed product records by manufacturer — FDA National Drug Code Directory. Record counts are not sales or prescription volume.
📈 How widely Pembrolizumab Injection is used
A general measure of how commonly Pembrolizumab Injection is prescribed, based on Medicaid — one of the largest public drug programs. The figure below is prescriptions filled in Q1–Q4 2025, summed across every form and brand of the drug.
Think of this as a proxy for how widely Pembrolizumab Injection is used, drawn from freely available public data. Medicaid is just one program — these numbers don’t include Medicare, other government coverage, or commercial and cash-pay prescriptions, so real-world use is higher than what’s shown here.
How commonly is Pembrolizumab Injection prescribed? Of the 1,596 medications we measure, Pembrolizumab Injection ranks #632 by Medicaid prescriptions — more than 60% of them.
Utilization by Pembrolizumab Injection product
Pick a product to see its own Medicaid numbers. Each chip is one clinical product — a specific strength & dosage form as defined by RxNorm — with brand-name and generic versions combined.
4 ML pembrolizumab 25 MG/ML Injection
Summed across the 2 of 3 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 1657750
Shares are of the Medicaid prescriptions shown here. Product grouping follows RxNorm (the National Library of Medicine’s drug terminology), so “one product” means one strength & dosage form regardless of manufacturer. Dollar figures are gross Medicaid reimbursement before mandatory rebates — rebates (often large, especially for brand-name drugs) are confidential, so actual net cost to Medicaid is lower than shown.
Source: Medicaid State Drug Utilization Data (CMS), aggregated by generic ingredient — summed across every NDC (all brands, strengths, salt forms and dosage forms) of Pembrolizumab Injection, and across all states and both fee-for-service and managed-care claims. A general popularity signal; it excludes Medicare, commercial insurance and cash prescriptions, so it is not total U.S. use. Based on the 2 of 3 listed Pembrolizumab Injection NDCs with Medicaid activity.
🔍 Compare Pembrolizumab Injection products
A representative set of FDA-listed product records for Pembrolizumab Injection — across manufacturers, strengths, and dosage forms, grouped by form with each product’s manufacturer and how the FDA approved it. The same medicine may be made and packaged by different companies, so a single drug can have many directory entries. (It’s also why a refill can look different — a new shape, color, or box — even though it contains the same medication.)
| Strength | Route | Manufacturer / Labeler | Category ⓘ | Details |
|---|---|---|---|---|
| 💊Injection | ||||
| 25 mg/mL | Intravenous | Merck Sharp & Dohme LLC × 6 listings | BLA | View NDC → |
| 25 mg/mL | — | MSD International GmbH (Singapore Branch) | DRUG FOR FURTHER PROCESSING | View NDC → |
| 25 mg/mL | — | MSD Ireland (Carlow) | DRUG FOR FURTHER PROCESSING | View NDC → |
Showing 8 of 8 products — FDA National Drug Code Directory. See every product, package size and price: browse all 8 Pembrolizumab Injection NDCs →
📈 What people report — real-world data (FDA FAERS)
After a medicine reaches the market, patients, doctors and drugmakers can send the FDA reports of problems they think may be linked to it. Here’s what’s been reported for Pembrolizumab Injection — a signal of what to watch for, not proof the drug caused it.
Source: openFDA, from the FDA Adverse Event Reporting System (FAERS). These are voluntary reports — they don’t prove the drug caused the effect, and counts reflect how often something was reported, not how often it actually happens. Reports also often name the very problem the medicine is taken for — a common reason to file one is that the drug didn’t help — so for a pain reliever you may see “pain” high on the list; that points to why the report was filed, not to the drug causing the symptom. This counts every report that lists Pembrolizumab Injection in any role, so the total runs higher than the FDA’s official dashboard, which counts only cases where the drug is the suspect. For the authoritative figures, see the FDA FAERS Public Dashboard. Always talk to your pharmacist or doctor.
🏛️ The road to your pharmacy
How Pembrolizumab Injection went from FDA review to the pharmacy shelf — the key milestones in its regulatory journey.
Source: Drugs@FDA.
🚨 Recall history
A recall is when a specific batch of a medicine is pulled from the market — usually a manufacturing issue, not a problem with the drug itself. Class I is most serious, Class III least.
Source: openFDA drug enforcement (recall) reports.
RxNorm Concept Web — From Ingredient to Every Form and Strength
This page starts with one ingredient concept (IN). The branches below show its dose-form concepts (SCDF), then the available clinical drug and strength concepts (SCD). Combination products remain separate concepts with their own pages.
RxCUI 1547545 1 dose form · 2 strengths
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Dose form (SCDF) Injection RxCUI 1657745In current FDA listings
Look up RxCUI 1547545 in the RxCUI Atlas →
RxNorm is the U.S. National Library of Medicine’s normalized drug vocabulary. Its concept hierarchy can include forms that are not currently marketed; the status on each branch compares that concept with current FDA listings. RxCUIs identify vocabulary concepts, not individual packages or manufacturers.
📦 Supply & shortage status
Whether Pembrolizumab Injection is in short supply in the U.S. right now, plus any shortage history the FDA has on record. A shortage usually reflects a manufacturing or demand issue — not a safety problem with the drug.
Source: openFDA, from the FDA Drug Shortages database.
🏷️ Sold under these brand names
🏭 Manufacturers & labelers
RxNorm drug class
Pembrolizumab Injection belongs to the Programmed Death Receptor-1 Blocking Antibody class.
Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.
🔬 Where this comes from
Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.
How we combine label and product data
HelloPharmacist combines public FDA and NLM records; we don’t author the underlying clinical facts. We identified 1 FDA-filed SPL label set within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. The representative label is the starting point for the displayed reference monograph; the 12 largest stored in-scope SPL records, which may include that representative, are compared section by section, and the longest available version of each section is retained. Forms, routes, brands, labelers, product-listed strengths, and product-record counts are aggregated separately from ingredient-matched FDA NDC Directory records; package records listed above are associated with the linked SPL; and the normalized concept hierarchy comes from NLM RxNorm.
Where a section is identified as AI-written, its plain-language text is generated from bounded label evidence. New draft drug pages remain in the admin review queue before first publication. Merck Sharp & Dohme LLC is the representative DailyMed label linked for verification and dates; it is not the sole source used for the page.
This is general education, not medical advice — always consult your doctor or pharmacist about your medications and any medical condition. For the exact wording of the linked representative label, view that label on DailyMed; some displayed composite sections may come from other in-scope SPL labels. Learn how we use AI and our data sources & update cadence.