Reading Your Prescription: What the Drug Name and Dose Mean
An immunotherapy prescription carries five things: a long generic molecule name, sometimes a brand name beside it, a dose in milligrams or mg/kg, a cycle interval such as Q3W, and a route — almost always an intravenous infusion. The generic name is the medicine. The brand name only tells you who made it.
Medically reviewed by Dr. Bharati Devi Gorantla, Medical Oncologist, MBBS · MD · DM (Adyar, Chennai) · ECMO · MRCP SCE (UK) · Last reviewed August 2026
What do the words on my immunotherapy prescription actually mean?
An immunotherapy prescription has five working parts: the molecule, the brand, the dose, the interval, and the route. The long word ending in -mab is the medicine. A name in brackets or capitals is the brand. A figure such as 200 mg or 2 mg/kg is your dose. A code such as Q3W is the gap between cycles. Everything else is usually pre-medication, a partner drug, or the blood tests ordered before each cycle.
Most people holding one of these sheets search the drug name they can see, not the drug class it belongs to. That single habit is why the same patient can read three pages about pembrolizumab without ever realising the box in their hand says Keytruda. The table below decodes the sheet in the order the lines usually appear on it.
| What you see written | What it means | Worth checking |
|---|---|---|
| Pembrolizumab | The generic (molecule) name. The suffix -mab means monoclonal antibody; -limab and -zumab are variants of it | Spelling. Several molecule names differ by two or three letters |
| (Keytruda) | A brand name — the manufacturer's label for that molecule, not a different medicine | That it belongs to the molecule written next to it |
| 100 mg / 4 mL | The vial strength and concentration. This is what the pharmacy stocks, not the dose you receive | Nothing — this is a pharmacy figure, not your dose |
| 200 mg IV or 2 mg/kg | Your actual dose. A flat dose is the same for everyone; a mg/kg dose is calculated from your body weight | If it is mg/kg, the weight used and the date it was recorded |
| Q3W, q21 days, D1 | The interval. One dose every three weeks, given on day one of each cycle | That the date on your next appointment slip matches it |
| x 4 cycles | A planned, countable number of doses. Some prescriptions instead read until progression or unacceptable toxicity, which is open-ended by design | Which of the two your plan is, and when it will next be reviewed |
| IV infusion over 30 min in NS 100 mL | How it is given: a drip into a vein, over half an hour, diluted in normal saline | Nothing — but it tells you how long the chair time will be |
| Day care / DCU | The setting. Checkpoint-inhibitor infusions are given as day care; admission overnight is not routine | Whether you need someone to travel back with you |
| Pre-med: pheniramine, paracetamol | Drugs given before the infusion to reduce reaction risk. Not the treatment itself | Any allergy you have to the pre-medication |
| TFT, LFT, RFT, cortisol | Blood tests ordered before cycles: thyroid, liver, kidney function and sometimes a morning cortisol | Where and how far in advance they are to be done |
Handwriting and hospital shorthand vary. If a line is genuinely illegible, the day-care pharmacy can read the entered order off the system — that copy is the one that will be dispensed.
Generic name or brand name — which one is the actual medicine?
The generic name is the medicine. The brand name is a company's label for it. Two boxes carrying different brand names can hold exactly the same molecule, and a biosimilar version adds a third name again. When you search online, search the generic name — that is the name guideline bodies such as NCCN, ASCO and ESMO use, and the name a CDSCO approval record is filed under.
| Generic name (the molecule) | Brand names seen in India | Class |
|---|---|---|
| Pembrolizumab | Keytruda | PD-1 inhibitor |
| Nivolumab | Opdivo, Opdyta; Indian biosimilars including Tishtha | PD-1 inhibitor |
| Cemiplimab | Libtayo | PD-1 inhibitor |
| Tislelizumab | Tevimbra | PD-1 inhibitor |
| Atezolizumab | Tecentriq | PD-L1 inhibitor |
| Durvalumab | Imfinzi | PD-L1 inhibitor |
| Ipilimumab | Yervoy | CTLA-4 inhibitor |
Being listed above does not mean a molecule is marketed in India, or approved for your particular cancer. Approval status moves. Tislelizumab, for example, received CDSCO approval and was launched in India in June 2025 under the brand Tevimbra; the Indian marketing status of some other molecules is best confirmed with your hospital pharmacy rather than assumed from an overseas approval. Checkpoint inhibitors approved in India goes through this molecule by molecule.
A biosimilar is not a generic copy in the way a tablet is. It is a separately manufactured biological product approved on its own comparability data, sold under its own brand name, and prescribed by the same molecule name — which is exactly why the generic name is the reliable one to read.
What should I verify on the prescription before the first infusion?
Six things, and none of them require medical training to check. A prescription is a working document that gets amended between cycles, and asking the day-care nurse or pharmacist to read it back to you is routine. Bring the sheet with you; do not rely on a photograph of an earlier version.
- The molecule name, spelled out. Confirm it matches what your oncologist said in the consultation, letter for letter.
- Flat dose or per kilogram. If the dose is written as mg/kg, ask which weight it was calculated from and when that weight was recorded.
- The interval, against your appointment date. Q3W and a slip dated four weeks later is worth one question before you leave the desk.
- The number of cycles, or the words that replace a number. A fixed count and an open-ended plan lead to very different conversations about cost and duration.
- Pre-medication and any partner drug. Flag any allergy, and ask which line on the sheet is the immunotherapy if you cannot tell.
- The blood tests listed, and when they are due. Thyroid, liver and kidney panels are usually needed before a cycle, not on the day.
One more thing to keep, though it is not on the prescription: a photograph of the vial label and batch number after each infusion. It is the only record that ties your treatment to a specific batch if a question ever arises later.
Who this explainer is not for
This page is for someone already holding an immunotherapy prescription written for them, who wants to read it without guessing. It is not a way to work out whether a checkpoint inhibitor is right for you, and it is not a shortcut past the consultation.
The medicines named here are not suitable for most patients. Eligibility depends on the cancer type, the stage, biomarker results such as PD-L1 or MSI status, organ function, and existing conditions. Anyone with an active autoimmune disease, an organ transplant on immunosuppression, or a previous severe immune-related reaction may be advised against them entirely. None of these medicines can be started, stopped, substituted, or re-dosed on the strength of anything read online.
This page is also not: a comparison of which molecule is better; a statement that any of them is available at, stocked by, or supplied through any particular hospital; a price list; or advice on sourcing a drug yourself. If you are on a clinical trial, the drug, dose and interval are set by the trial protocol and your prescription may look different again — ask your trial coordinator, not a general explainer.
What does mg/kg, Q3W and x 4 cycles mean on the dose line?
The dose line is three pieces of information written as one string: how much, how often, and for how long. Read it left to right — amount first, interval second, duration last. Three distinctions inside it are worth understanding, because each one changes what the rest of your treatment will look like.
Flat dose or weight-based. A figure written as 200 mg is a flat dose, the same for every adult on that indication. A figure written as 2 mg/kg is calculated from your body weight, so it moves if your weight moves materially — which is one reason the day-care unit weighs you before a cycle rather than reusing the number from last month.
Counted or open-ended. A prescription reading x 4 cycles has a defined end point you can plan and budget around. One reading until progression or unacceptable toxicity has no fixed number by design: it continues while it is working and being tolerated, and is reconsidered at each scan. The second is not a longer version of the first — it is a different kind of plan, and worth asking when it will next be reviewed.
The same medicine can have two schedules. 400 mg Q6W and 200 mg Q3W can be two approved schedules of one drug rather than two different strengths. If yours switches between them, that is usually a scheduling decision — fewer hospital visits for the same total exposure — not a dose increase. Q2W, Q4W and Q6W read the same way: every two, four or six weeks. D1 means the drug is given on day one of each cycle.
A cycle postponed for a blood result or a side effect is common and does not restart the count. The interval on the prescription is the plan, not a deadline.
Why is a chemotherapy drug written on the same prescription?
Because several checkpoint inhibitors are approved only as part of a fixed combination, not on their own. In those regimens the chemotherapy is part of the same treatment, prescribed together and given in the same sitting. A prescription that names two or three drugs is usually one regimen, not two competing plans.
Three kinds of line commonly sit alongside the immunotherapy. A partner drug — chemotherapy, or in some regimens a second checkpoint inhibitor such as ipilimumab, which is used in combination rather than alone; Ipilimumab (Yervoy): Uses, Cost and Why It Is Combined covers why that pairing exists. Pre-medication — an antihistamine, paracetamol, intravenous fluids, or anti-nausea drugs, given to reduce infusion reactions and chemotherapy side effects. And monitoring orders — the blood panels drawn before each cycle to catch an immune-related reaction early, which is why they appear on a treatment sheet at all.
If you genuinely cannot tell which line is the immunotherapy, the molecule name ending in -mab is almost always it. Ask your oncologist to mark it once, in pen, on your copy.
Does the prescription tell me whether the vial I receive is genuine?
No. A prescription names the molecule and the dose; it says nothing about the specific vial dispensed against it. Verification happens at the pharmacy counter, not on the sheet — batch number, expiry date, manufacturer, any hologram or authentication code the manufacturer uses, and documented cold-chain handling from storage to infusion.
This matters more than it used to. Counterfeit checkpoint inhibitors have been reported entering the Indian market, and the incentive rose as biosimilars arrived ahead of patent expiry. Sourcing through a licensed hospital pharmacy, watching the vial being reconstituted, and photographing the label after each infusion are reasonable, ordinary precautions — how to check an immunotherapy vial is genuine sets out what to look for.
Cost figures you may see written on a pharmacy indent are indicative only, as of August 2026, and vary with dose, brand or biosimilar, and hospital. A prescription is a clinical order, not a quotation.
Reading an Immunotherapy Prescription: Frequently Asked Questions
What do the words on an immunotherapy prescription mean?
An immunotherapy prescription has five working parts. The long generic name ending in -mab is the molecule itself. A name in brackets or capitals is the brand. A figure such as 200 mg or 2 mg/kg is your dose. A code such as Q3W is the gap between cycles. A line such as IV infusion over 30 minutes is how it is given. Everything else on the sheet is usually pre-medication, a chemotherapy partner drug, or the blood tests ordered before each cycle.
Is the generic name or the brand name the actual medicine?
The generic name is the medicine. Pembrolizumab, nivolumab, atezolizumab, durvalumab, ipilimumab, cemiplimab and tislelizumab are molecules. Keytruda, Opdyta, Tecentriq, Imfinzi, Yervoy, Libtayo and Tevimbra are brand names those molecules are sold under. Two boxes with different brand names can hold the same molecule, and a biosimilar carries a third name again. When you search online, search the generic name — that is the name guideline documents and approval records use.
What should I check on my immunotherapy prescription before the first infusion?
Check six things, and ask about anything that does not match. The molecule name, spelled exactly as your oncologist said it. Whether the dose is flat or per kilogram, and if per kilogram, the weight it was calculated from. The interval between cycles. The planned number of cycles, or the words that replace a number. The pre-medication and any partner drug. The blood tests ordered before each cycle. A prescription is a working document, and asking the day-care nurse to read it back to you is routine, not rude.
What does Q3W mean on my prescription?
Q3W means one dose every three weeks. Q2W is every two weeks, Q4W every four, Q6W every six. The interval belongs to the dose written beside it, so 400 mg Q6W and 200 mg Q3W can be two schedules of the same medicine rather than two different strengths. D1 means the drug is given on day one of each cycle. If a cycle is postponed for a blood result or a side effect, the interval on the prescription is the plan, not a deadline.
Why is chemotherapy written on the same prescription as immunotherapy?
Several checkpoint inhibitors are approved only as part of a fixed combination, so the chemotherapy agents are part of the same regimen rather than a separate treatment. A prescription may also carry pre-medication such as an antihistamine or paracetamol, intravenous fluids, and anti-nausea drugs for the chemotherapy component. If you cannot tell which line is the immunotherapy, the molecule name ending in -mab is almost always it. Ask your oncologist to mark it for you.
Does the prescription tell me whether the vial is genuine?
No. A prescription names the molecule and the dose. It says nothing about the specific vial dispensed against it. Verification happens at the pharmacy counter — batch number, expiry date, manufacturer, holograms where the manufacturer uses them, and documented cold-chain handling. Counterfeit checkpoint inhibitors have been reported entering the Indian market, so sourcing through a licensed hospital pharmacy and keeping the batch details matters. This is a patient-safety point, not a cost one.