What the label lists and what reports show

Procarbazine side effects

Procarbazine's FDA label: “Nausea and vomiting are the most commonly reported side effects.” FAERS holds 4,488 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is nausea (973 reports).

No generic listed
Boxed warning

Check it at the source: the procarbazine FDA label on DailyMed (effective September 16, 2024, Leadiant Biosciences, Inc.); the FDA FAERS public dashboard.

What does the label list?

From the label: adverse reactions
Nausea and vomiting are the most commonly reported side effects.

From the label: adverse reactions, continued
Leukopenia, anemia and thrombopenia occur frequently. Nausea and vomiting are the most commonly reported side effects. Other adverse reactions are: Hematologic Pancytopenia; eosinophilia; hemolytic anemia; bleeding tendencies such as petechiae, purpura, epistaxis and hemoptysis. Gastrointestinal Hepatic dysfunction, jaundice, stomatitis, hematemesis, melena, diarrhea, dysphagia, anorexia, abdominal pain, constipation, dry mouth. Neurologic Coma, convulsions, neuropathy, ataxia, paresthesia, nystagmus, diminished reflexes, falling, foot drop, headache, dizziness, unsteadiness. Cardiovascular Hypotension, tachycardia, syncope. Ophthalmic Retinal hemorrhage, papilledema, photophobia, diplopia, inability to focus. Respiratory Pneumonitis, pleural effusion, cough. Dermatologic Herpes, dermatitis, pruritus, alopecia, hyperpigmentation, rash, urticaria, flushing. Allergic Generalized allergic reactions. Genitourinary Hematuria, urinary frequency, nocturia. Musculoskeletal Pain, including myalgia and arthralgia; tremors. Psychiatric Hallucinations, depression, apprehension, nervousness, confusion, nightmares. Endocrine Gynecomastia in prepubertal and early pubertal boys. Miscellaneous Intercurrent infections, hearing loss, pyrexia, diaphoresis, lethargy, weakness, fatigue, edema, chills, insomnia, slurred speech, hoarseness, drowsiness.

Source: FDA drug label, Leadiant Biosciences, Inc., effective September 16, 2024 (SPL set 1aa75a3a-18c9-49e1-91a6-293d0b7da756), via openFDA; the full label on DailyMed

What do FAERS reports show?

4,488 reports list procarbazine among the medicines taken, each a report of something that happened, not proof the medicine caused it; 323 are coded as a death and 580 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 22 reactions below, 13 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.

Reports received each year

The 25 most reported reactions

Nausea (named in the label)973
Fatigue (named in the label)829
Vomiting (named in the label)304
Constipation (named in the label)265
Platelet Count Decreased239
White Blood Cell Count Decreased229
Decreased Appetite177
Headache (named in the label)172
Rash (named in the label)148
Diarrhoea (named in the label)135
Blood Count Abnormal132
Neutropenia132
Dizziness (named in the label)104
Urticaria (named in the label)103
Thrombocytopenia100
Disease Progression (a use or a product term, not a reaction)95
Pyrexia (named in the label)80
Death (an outcome recorded in the report)78
Asthenia71
Pain67
Drug Ineffective (a use or a product term, not a reaction)65
Neuropathy Peripheral63
Paraesthesia (named in the label)63
Stomatitis (named in the label)63
Anaemia (named in the label)62

Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms

What next?

Procarbazine: the full record: label, generics, price, shortages, recalls
Report a side effect to the FDA: MedWatch
Side effects hub: the most reported medicines and reactions