promethazine and codeine, Phenergan with Codeine (cont.)

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Promethazine should not be used with propylthiouracil (PTU) due to the increased risk of low white blood cell counts and increased risk of infections. The reason for this interaction is not known.

Concurrent use of promethazine with the dye used for myelography (X-rays of the spinal cord) can lower the threshold for seizures and thus increase the risk of seizures. Promethazine should be stopped at least 48 hours before myelography and not restarted until at least 24 hours after myelography.

PREGNANCY: There are no adequate studies of promethazine and codeine in pregnant women. Administration of promethazine within two weeks of delivery may affect platelet function in the newborn. Codeine generally is avoided during pregnancy because it may cause fetal physical dependence, withdrawal and growth retardation.

NURSING MOTHERS: It is not known if promethazine is excreted in breast milk. Small amounts of codeine are secreted in breast milk, but the risk of adverse events in the infant is small.

SIDE EFFECTS: Promethazine often causes sedation. In children less than two years of age, it can depress respiration and lead to death. Therefore, it should not be used in children less than two years old. Dizziness also may occur. Ironically, promethazine sometimes stimulates activity in patients, particularly children. Such stimulation may be manifest by restlessness, inability to sleep, palpitations (rapid heartbeat) or even seizures. Promethazine also causes anticholinergic side effects such as blurred vision, dry mouth, dilated pupils, nausea, urinary retention (inability to urinate), impotence, and constipation.

EPS may occur. EPS are categorized as dystonic reactions (alterations in muscle tone), sharp, involuntary muscle movements often limited to one muscle or muscle group, akathisia (subjective restlessness), and Parkinsonism. Parkinsonian symptoms are more common in older persons whereas children more often develop involuntary muscle movement reactions. Dystonic reactions are most commonly seen during the first week of treatment. Restlessness and Parkinsonian symptoms usually develop days to weeks after starting therapy.



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