Promethazine

Concomitant use of other agents with anticholinergic properties should be undertaken with caution.

Promethazine may increase, prolong, or intensify the sedative action of central-nervous-system depressants, such as alcohol, sedative/hypnotics (including barbiturates), general anesthetics, narcotics, narcotic analgesics, tricyclic antidepressants, and tranquilizers; therefore, such agents should be avoided or administered in reduced dosage to patients receiving promethazine hydrochloride. When given concomitantly with promethazine, the dose of barbiturates should be reduced by at least one-half, and the dose of narcotics should be reduced by one-quarter to one-half. Dosage must be individualized. Excessive amounts of promethazine relative to a narcotic may lead to restlessness and motor hyperactivity in the patient with pain; these symptoms usually disappear with adequate control of the pain.

Antihistamines have an added antimuscarinic effect with other antimuscarinic drugs such as atropine and tricyclic antidepressants.

Because of the potential for promethazine hydrochloride to reverse epinephrine’s vasopressor effect, epinephrine should NOT be used to treat hypotension associated with promethazine overdose.

Promethazine may interfere with immunologic urine pregnancy tests to produce false positive or negative results.

In patients with asthma or other respiratory disorders (eg bronchitis or bronchiectasis), glaucoma, epilepsy, urinary retention, prostatic hypertrophy, hepatic or renal impairment, cardiovascular problems or pyloroduodenal obstruction the product should only be taken after consulting a doctor.

Promethazine hydrochloride should be discontinued at least 72 hours before the start of skin tests as it may inhibit the cutaneous histamine response thus producing false negative results.

Promethazine should be used with caution in patients with seizure disorders or in patients receiving medication which may affect the seizure threshold because of risk of convulsions.

The advice of a doctor should be sought before use.

Promethazine should not be used in pregnancy unless the physician considers it essential. The use of promethazine is not recommended in the 2 weeks prior to delivery in view of the risk of irritability and excitement in the neonate.

The advice of a doctor should be sought before use.

Available evidence suggests that the amount excreted in milk is insignificant. However, there are risks of neonatal irritability and excitement.

This product causes drowsiness. Do not drive or operate machinery.

Ambulant patients receiving promethazine for the first time should not be in control of vehicles or machinery for the first few days until it is established that they are not hypersensitive to the central nervous effects of the drug and do not suffer from disorientation, confusion or dizziness.