promethazine and codeine, Phenergan with Codeine (cont.)
Omudhome Ogbru, PharmD
Omudhome Ogbru, PharmD
Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.
Medical and Pharmacy Editor:
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.
A complex called neuroleptic malignant syndrome (NMS) can occur in patients receiving phenothiazines. NMS consists of high body temperature, severe EPS, changes in consciousness and mental status, and increased heart rate with low or high blood pressure. NMS occurs more frequently in young men and in persons who are dehydrated.
Rarely, blood cell disorders can occur; low white cell counts can lead to severe infections.
Phenothiazines such as promethazine can cause skin hyperpigmentation (darkening) but usually only after prolonged use. The effect usually is restricted to areas of the body exposed to sunlight. Thus, people who need long-term treatment with promethazine should either keep out of the sun or use effective sunscreens.
Phenothiazines can cause blurred vision, difficulty with nighttime vision, or changes in color vision.
Liver damage has been reported rarely with phenothiazines. Jaundice is possible. Jaundice also may occur in newborns of mothers who receive phenothiazines during pregnancy.
Phenothiazines such as promethazine block dopamine receptors. This effect can lead to increases in blood levels of prolactin, a hormone involved in lactation (formation of breast milk). As a result, phenothiazines can cause the breast to produce fluid ("milk") even when a woman is not pregnant. Additionally, phenothiazines can cause missed menstrual periods, breast enlargement or tenderness, loss of sexual drive, impotence, inability to ejaculate, and priapism (prolonged penile erection). Weight gain also may occur.
The most frequent side effects of codeine include lightheadedness, dizziness, nausea, vomiting, shortness of breath, and sedation. Other side effects include allergic reactions, constipation, abdominal pain, rash, and itching. Codeine is habit forming. Mental and physical dependence can occur but are unlikely when used for short-term pain relief. If codeine is suddenly withdrawn after prolonged use, symptoms of withdrawal may develop. The dose of codeine should be reduced gradually in order to avoid withdrawal symptoms.
Reference: FDA Prescribing Information
Last Editorial Review: 11/1/2010
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