When given concomitantly with promethazine hydrochloride injection, 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. Use of syringes with rigid plungers or of small-bore needles might obscure typical arterial backflow if this is relied upon alone.In the event that a patient complains of pain during intravenous injection of promethazine hydrochloride injection, the injection should be stopped immediately to evaluate for possible arterial injection or perivascular extravasation.There is no proven successful management of unintentional intra-arterial injection or perivascular extravasation after it occurs. Daily doses of 25 mg/kg intraperitoneally have been found to produce fetal mortality in rats.There are no adequate and well-controlled studies of promethazine hydrochloride injection in pregnant women. The concomitant use of alcohol, sedative/hypnotics (including barbiturates), general anesthetics, narcotics, narcotic analgesics, tricyclic antidepressants, and tranquilizers may enhance impairment (see Patients should be advised to report any involuntary muscle movements (see Patients should be advised to avoid prolonged exposure to the sun (see Promethazine hydrochloride injection 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. Promethazine is a competitive HPromethazine hydrochloride injection is indicated for the following conditions:Promethazine hydrochloride injection is contraindicated for use in pediatric patients less than two years of age due to the risk of respiratory depression Promethazine hydrochloride injection is contraindicated in comatose states.Under no circumstances should promethazine hydrochloride injection be given by intra-arterial injection due to the likelihood of severe arteriospasm and the possibility of resultant gangrene (see Promethazine hydrochloride injection should not be given by the subcutaneous route because evidence of chemical irritation has been noted, and necrotic lesions have resulted following subcutaneous injection. 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.) Pediatric patients should be supervised to avoid potential harm in bike riding or in other hazardous activities. Do not use if there is a precipitate or any sign of incompatibility.The average adult dose is 25 mg. Sympathetic block and heparinization have been employed during the acute management of unintentional intra-arterial injection, because of the results of animal experiments with other known arteriolar irritants.Carcinogenesis, Mutagenesis and Impairment of FertilityGeriatric Use (patients approximately 60 years or older)damage to tissues regardless of the route of administrationdamage to tissues regardless of the route of administrationThe preferred parenteral route of administration for promethazine hydrochloride injection is by deep intramuscular injection.When administered intravenously, promethazine hydrochloride injection should be given in a concentration no greater than 25 mg per mL and at a rate not to exceed 25 mg per minute.Promethazine hydrochloride injection is contraindicated for use in pediatric patients less than 2 years of age (see). There may be an increased risk of side effects if this medication is given by injection into a vein. Aspiration of dark blood does not preclude intra-arterial needle placement because blood is discolored upon contact with promethazine hydrochloride injection. Keep covered in carton until time of use.Do not use if solution has developed color or contains a precipitate.We comply with the HONcode standard for trustworthy health information - GENERIC NAME: PROMETHAZINE - INJECTION (pro-METH-uh-zeen) It should be inspected before use and discarded if either color or particulate is observed.Promethazine hydrochloride is a phenothiazine derivative which possesses antihistaminic, sedative, antimotion-sickness, antiemetic, and anticholinergic effects. This possibility should be considered with promethazine hydrochloride injection.The following laboratory tests may be affected in patients who are receiving therapy with promethazine hydrochloride injection:Diagnostic pregnancy tests based on immunological reactions between HCG and anti-HCG may result in false-negative or false-positive interpretations.An increase in blood glucose has been reported in patients receiving promethazine hydrochloride.Long-term animal studies have not been performed to assess the carcinogenic potential of promethazine hydrochloride injection, nor are there other animal or human data concerning carcinogenicity, mutagenicity, or impairment of fertility. When used for control of postoperative nausea and vomiting, the dosage of analgesics and barbiturates should be reduced accordingly (see Antiemetics should not be used in vomiting of unknown etiology in children and adolescents (see As an adjunct to preoperative or postoperative medication, 25 to 50 mg of promethazine hydrochloride injection in adults may be combined with appropriately reduced doses of analgesics and atropine-like drugs as desired. This medication must not be given by injection under the skin.Information last revised December 2013. Diazepam may be used to control convulsions.