What the label lists and what reports show
Codeine and promethazine side effects
Codeine and promethazine's FDA label: “The most common adverse reactions to Promethazine HCl and Codeine Phosphate Oral Solution include: Sedation (somnolence, mental clouding, lethargy), impaired mental and physical performance, lightheadedness, dizziness, headache, dry mouth, nausea, vomiting …” FAERS holds 3,559 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 dependence (3,495 reports).
- Generic listed
- Boxed warning
- DEA Schedule V
Check it at the source: the codeine and promethazine FDA label on DailyMed (effective December 18, 2025, Cosette Pharmaceuticals, Inc.); the FDA FAERS public dashboard.
What does the patient leaflet say about side effects?
From the patient leaflet: What are the possible side effects of Promethazine Hydrochloride and Codeine Phosphate Oral Solution?Promethazine Hydrochloride and Codeine Phosphate Oral Solution may cause serious side effects, including: See “What is the most important information I should know about Promethazine Hydrochloride and Codeine Phosphate Oral Solution?” Bowel problems including severe constipation or stomach pain. See “Who should not take Promethazine Hydrochloride and Codeine Phosphate Oral Solution?” Increased pressure in your head (increased intracranial pressure). Avoid the use of Promethazine Hydrochloride and Codeine Phosphate Oral Solution if you have a head injury or have been told that you have changes in the tissue of your brain (brain lesions) or increased pressure in your head. Neuroleptic malignant syndrome (NMS) which can lead to death. […]
Source: FDA drug label, Cosette Pharmaceuticals, Inc., effective December 18, 2025 (SPL set 3b02cda4-9b24-79c9-e063-6294a90af5b9), via openFDA; the full label on DailyMed
What does the label list?
From the label: adverse reactionsThe most common adverse reactions to Promethazine HCl and Codeine Phosphate Oral Solution include: Sedation (somnolence, mental clouding, lethargy), impaired mental and physical performance, lightheadedness, dizziness, headache, dry mouth, nausea, vomiting, constipation, shortness of breath, sweating.
From the label: adverse reactions, continuedThe following serious adverse reactions are described, or described in greater detail, in other sections: Addiction, abuse, and misuse [ see Warnings and Precautions (5.1), Drug Abuse and Dependence (9.3) ] Life-threatening respiratory depression [ see Warnings and Precautions (5.2, 5.3 , 5.4 , 5.5 , 5.6 ), Overdosage (10) ] Ultra-rapid metabolism of codeine and other risk factors for life-threatening respiratory depression in children [ see Warnings and Precautions (5.3) ] Accidental overdose and death due to medication errors [ see Warnings and Precautions (5.7) ] Decreased mental alertness with impaired mental and/or physical abilities [ see Warnings and Precautions (5.8) ] Interactions with benzodiazepines and other CNS depressants [ see Warnings and Precautions (5.10) ] Paralytic ileus, gastrointestinal adverse reactions [ see Warnings and Precautions (5.11) ] Increased intracranial pressure [ see Warnings and Precautions (5.12) ] Obscured clinical course in patients with head injuries [ see Warnings and Precautions (5.12) ] Neuroleptic Malignant Syndrome [ see Warnings and Precautions (5.13) ] Paradoxical reactions, including dystonias [ see Warnings and Precautions (5.14) ] Seizures [ see Warnings and Precautions (5.15) ] Interactions with MAOI [ see Warnings and Precautions (5.16) ] Bone marrow suppression [ see Warnings and Precautions (5.17) ] Severe hypotension [ …
Source: FDA drug label, Cosette Pharmaceuticals, Inc., effective December 18, 2025 (SPL set 3b02cda4-9b24-79c9-e063-6294a90af5b9), via openFDA; the full label on DailyMed
What do FAERS reports show?
3,559 reports list codeine and promethazine among the medicines taken, each a report of something that happened, not proof the medicine caused it; 165 are coded as a death and 8 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. Reports rose sharply in 2023 (3,437, against a median of 1 a year): FAERS counts follow reporting, which news, litigation and label changes can drive, not how often a reaction happens. Of the 23 reactions below, 3 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
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Codeine and promethazine: 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