Dextromethorphan / promethazine Side Effects

Some side effects of dextromethorphan / promethazine may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

For the Consumer

Applies to dextromethorphan / promethazine: oral syrup

Get emergency medical help if you have any of these signs of an allergic reaction while taking dextromethorphan / promethazine: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Stop using dextromethorphan and promethazine and call your doctor at once if you have any of these serious side effects:

• uncontrollable movements of your eyes, lips, tongue, face, arms, or legs;

• tremors, twitching, or uncontrolled muscle movements in your face, arms, or legs.

• severe dizziness, anxiety, restless feeling, or nervousness;

• hallucinations (seeing or hearing things);

• confusion, hallucinations; or

• slow, shallow breathing, weak pulse;

• nausea, stomach pain, low fever, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes); or

• fever, muscle stiffness, confusion, fast or uneven heartbeat, sweating, fainting.

Keep taking dextromethorphan and promethazine and talk with your doctor if you have any of these less serious side effects:

• dizziness, drowsiness, sleepiness, or confusion;

• blurred vision, dry mouth;

• ringing in your ears;

• nausea or vomiting; or

• increased sensitivity to sunlight.

Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.

For Healthcare Professionals

Applies to dextromethorphan / promethazine: oral syrup

Nervous system

Nervous system side effects have included tinnitus, drowsiness, dizziness, sedation, somnolence, confusion, disorientation, lassitude, incoordination, fatigue, euphoria, nervousness, insomnia, tremors, convulsive seizures, excitation, catatonic-like states, hysteria, hallucinations, and extrapyramidal symptoms such as oculogyric crisis, torticollis, and tongue protrusion

Gastrointestinal

Gastrointestinal side effects have included dry mouth, nausea, vomiting, and gastrointestinal disturbances.

Cardiovascular

Cardiovascular side effect have included increased or decreased blood pressure, tachycardia, bradycardia, and faintness.

Hepatic

Hepatic side effects have included jaundice.

Hematologic

Hematologic side effects have included leukopenia, thrombocytopenia, thrombocytopenic purpura, and agranulocytosis.

Dermatologic

Dermatologic side effects have included dermatitis, photosensitivity, and urticaria.

Respiratory

Respiratory side effects have included asthma, nasal stuffiness, respiratory depression (potentially fatal) and apnea (potentially fatal).

Hypersensitivity

Hypersensitivity side effects ave included angioneurotic edema.

Other

Other side effects have included neuroleptic malignant syndrome (potentially fatal).

A potentially fatal symptom complex sometimes referred to as Neuroleptic Malignant Syndrome (NMS) has been reported in association with promethazine alone or in combination with antipsychotic drugs. Clinical manifestations of NMS are hyperpyrexia, muscle rigidity, altered mental status and evidence of autonomic instability (irregular pulse or blood pressure, tachycardia, diaphoresis and cardiac dysrhythmias). The diagnostic evaluation of patients with this syndrome is complicated. In arriving at a diagnosis, it is important to identify cases where the clinical presentation includes both serious medical illness (e.g., pneumonia, systemic infection, etc.) and untreated or inadequately treated extrapyramidal signs and symptoms (EPS). Other important considerations in the differential diagnosis include central anticholinergic toxicity, heat stroke, drug fever and primary central nervous system (CNS) pathology.

The management of NMS should include 1) immediate discontinuation of promethazine, antipsychotic drugs, if any, and other drugs not essential to concurrent therapy, 2) intensive symptomatic treatment and medical monitoring, and 3) treatment of any concomitant serious medical problems for which specific treatments are available. There is no general agreement about specific pharmacological treatment regimens for uncomplicated NMS. Since recurrences of NMS have been reported with phenothiazines, the reintroduction of promethazine should be carefully considered.

Other side effects have included paradoxical reactions. Hyperexcitability and abnormal movements have been reported in patients following a single administration of promethazine. Consideration should be given to the discontinuation of promethazine and to the use of other drugs if these reactions occur. Respiratory depression, nightmares, delirium, and agitated behavior have also been reported in some of these patients.

Ocular

Ocular side effects have included blurred vision and diplopia.

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