What Is CAPOX or XELOX Chemotherapy?

CAPOX and XELOX are the same thing. CAP is capecitabine, XEL is Xeloda, the brand name for capecitabine, and OX is oxaliplatin. Some centers use one abbreviation, some the other.

What makes this regimen unusual is the split. Oxaliplatin is an infusion given in the chair. Capecitabine is a tablet you take at home, twice a day, for two weeks straight. Most of the treatment happens with nobody watching, which is why the home instructions carry more weight here than in a fully intravenous regimen.

The capecitabine label states the combination clearly. Capecitabine is 1,000 mg/m2 by mouth twice daily for the first 14 days of each 21-day cycle. Oxaliplatin is given intravenously on day 1 of each cycle, at an amount the unit works out from your body size.

The capecitabine part matters because you take it yourself at home, and the 14-days-on, 7-days-off rhythm is easy to lose track of. Work from the prescription and the calendar your own team gave you: their figures, not these, are the ones to fill and swallow. Ring them rather than guessing if you miss a dose or if mouth soreness, diarrhoea or hand-and-foot pain starts.

For colon cancer treatment after surgery, the label caps this at a maximum of 8 cycles. For metastatic colorectal cancer it continues until the disease progresses or side effects become unacceptable. For gastric or gastroesophageal cancer the capecitabine dose may be 850 mg/m2 or 1,000 mg/m2 twice daily on the same 14-days-on, 7-days-off pattern.

Note that 1,000 mg/m2 is lower than the 1,250 mg/m2 used when capecitabine is given alone. If your dose looks smaller than a friend's, that may be why.

Days 15 to 21 are deliberately drug-free. That week is not a gap in the plan. It is the plan.

The label is specific: swallow the tablets whole with water within 30 minutes after a meal. Do not chew, cut, or crush them.

That 30-minute window is a real instruction, not a suggestion. Absorption was studied that way. Set an alarm for both doses, roughly 12 hours apart, and take each one right after eating.

If you miss a dose, do not double up. Call the clinic and ask what to do with the rest of that day.

Capecitabine carries a boxed warning about DPD deficiency. DPD, short for dihydropyrimidine dehydrogenase, is the enzyme that breaks the drug down. People who lack it completely cannot clear the drug, and the label states that serious adverse reactions or death may occur.

The instruction is direct: test patients for genetic variants of the DPYD gene before starting capecitabine, unless treatment cannot wait. Avoid the drug entirely in people with certain homozygous or compound heterozygous DPYD variants that cause complete deficiency. The label adds that no dose has been proven safe in that group.

For partial deficiency the label says to individualize the dose. If nobody mentioned DPYD testing to you, ask whether it was done and what the result was.

Capecitabine's second boxed warning concerns vitamin K antagonists, most commonly warfarin. The label reports altered clotting values and bleeding, including deaths, in people taking both.

If you take warfarin, this needs an explicit plan, usually much more frequent INR checks or a switch to a different anticoagulant. Bring your full medicine list, including anything prescribed by a cardiologist.

Oxaliplatin causes an acute neuropathy unlike anything in other chemotherapy. It appears within hours to 2 days of a dose, usually resolves within 14 days, and comes back with the next dose.

Cold triggers it. The label describes transient tingling, altered sensation, or numbness in the hands, feet, around the mouth, or in the throat. It also lists jaw spasm, an odd feeling in the tongue, slurred speech, eye pain, and a sensation of chest pressure. This acute pattern occurred in about 56% of patients overall and in roughly 30% of patients in any individual cycle.

There is a related throat symptom. Pharyngolaryngeal dysesthesia, a feeling of difficulty swallowing or breathing, occurred at grade 3 to 4 in 1% to 2% of previously untreated patients with advanced colorectal cancer. The label notes that in patients previously treated, this happened without any actual laryngospasm or bronchospasm, meaning no stridor and no wheezing. It is frightening and usually not dangerous, but it must be reported, because it cannot be told apart from a true allergic reaction at home.

The label also gives one clear prohibition: avoid topical ice, including ice chips used to protect the mouth, because cold makes these symptoms worse. This matters because sucking ice is standard advice with several other chemotherapy drugs.

Practical version: no cold drinks, no ice, no bare hands in the fridge or freezer, and cover your face outdoors in winter for several days after each infusion.

The delayed form is different and more consequential. The label defines it as lasting more than 14 days, with numbness, tingling, and loss of position sense that can interfere with writing, buttoning, swallowing, and walking. It occurred in 48% of patients receiving oxaliplatin.

For grade 3 sensory neuropathy, the median time to onset was 9 cycles in the after-surgery setting and 6 cycles in previously treated advanced disease. That is why teams often stop oxaliplatin before the planned cycle count while continuing capecitabine. Report changes early, while a dose reduction can still prevent permanent damage. Peripheral neuropathy covers how it is graded and managed.

Serious and fatal allergic reactions, including anaphylaxis, can occur within minutes of the infusion and during any cycle, not just the first. Once such a reaction happens, oxaliplatin is stopped permanently and never restarted.

The label notes that lengthening the infusion from 2 hours to 6 hours may reduce non-life-threatening infusion reactions. If you had a mild reaction, that is a specific option to ask about.

Hand-foot syndrome, named palmar-plantar erythrodysesthesia on the label, is among the most common reactions to capecitabine, at 30% or more in colon cancer treatment. Redness, tingling, peeling, and pain on the palms and soles can make walking hard. The label instructs that capecitabine be withheld, then restarted at the same or a reduced dose, or stopped, depending on severity. Hand-foot syndrome covers prevention.

Diarrhea is the other. In 875 patients on single-agent capecitabine, the median time to first grade 2 to 4 diarrhea was 34 days, with a range from 1 day to 1 year. Median duration of grade 3 to 4 diarrhea was 5 days. Colorectal cancer covers where this regimen fits in treatment.

The label also states capecitabine is not recommended if your neutrophil count is below 1.5 x 10 to the 9th per liter or platelets are below 100 x 10 to the 9th per liter at baseline.

Holding the tablets for a day or two is a normal part of this regimen. Pushing through is what causes admissions.

• Call 911 or go to an emergency department if throat tightness, trouble swallowing, or chest pressure appears during or soon after an oxaliplatin infusion. At home this cannot be told apart from a true allergic reaction, and serious allergic reactions can occur within minutes, in any cycle.
• Stop the tablets and call your oncology team straight away, at any hour, if your temperature reaches 100.4 degrees F (38 C). MedlinePlus, reviewed October 2024, uses 100.4 F; NCI's infection page, reviewed January 2020, uses 100.5 F. Use the lower, newer number. This is the one symptom here that must not wait for office hours: CDC classes a fever on chemotherapy as a medical emergency, and capecitabine plus oxaliplatin can leave you short of neutrophils. If the team cannot be reached quickly, go to an emergency department and say you are on chemotherapy.
• Stop the tablets and call your care team the same day if you have 4 or more bowel movements a day above your normal, or any diarrhea overnight, or you vomit and cannot keep fluids or tablets down.
• Stop the tablets and call your care team the same day if sores in your mouth stop you eating or drinking normally, or your palms or soles blister, crack, or hurt enough to change how you walk.
• Call your care team within a day or two if tingling or numbness is still there more than 14 days after an infusion, or you start dropping things, fumbling buttons, or feeling unsteady on your feet. Reported early, this can still be headed off with a dose change.

• https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=e702d84d-7162-4751-bf37-d724cc7e45a5
• https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=7dc8dfb1-dec8-43b3-b2ea-05eac054b2c6
• https://www.cancer.gov/about-cancer/treatment/side-effects/infection
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• https://www.cdc.gov/cancer-preventing-infections/patients/fever.html