Precautions for the substance Prometazine
May inhibit the cough reflex; therefore, caution is necessary in patients (especially children) with exacerbations of chronic respiratory diseases. Caution should be exercised in patients with liver dysfunction, cardiovascular system disorders and suppression of medullary hematopoiesis. In the elderly, caution is required when parenteral administration promethazine of high doses, because extrapyramidal disorders and acute urinary retention are possible. In case of long-term use, peripheral blood cell composition should be periodically monitored. As an antiemetic agent it should be used only in case of prolonged vomiting of known etiology. Caffeine administration is recommended to prevent CNS depression. Long-term use increases the risk of dental disease (caries, periodontitis, candidiasis) due to reduced salivation. May mask the ototoxic effect (tinnitus and dizziness) of co-administered drugs. Increases the need for riboflavin. It is not recommended to use for drivers of vehicles and people with professions connected with high concentration (especially at the beginning of treatment). It is necessary to exclude alcohol consumption during the treatment.
It is not suitable for injection intravenously or by injection. Some dosage forms of promethazine contain sodium metabisulfite, which may cause allergic reactions, including anaphylactoid and asthmatic reactions. To prevent distorted results of skin scarification tests for allergens, it is necessary to cancel 72 h before allergy testing. False positive pregnancy test results are possible during treatment.
Use with caution in acute or chronic respiratory diseases because promethazine suppresses the cough reflex.
The use of promethazine in combination with opioid analgesics and tranquilizers for complex preoperative preparation of patients is possible only under strict medical supervision. During long-term treatment it is recommended to perform systematic general blood analysis and control of liver function parameters. It is not allowed to drink alcohol during treatment. Use with caution in children with acute or chronic respiratory diseases since promethazine suppresses the cough reflex. It is not recommended for use in children to stop episodic vomiting of unspecified genesis. Effect on the ability to drive and operate machinery During the initial, individually determined period of promethazine administration, it is not allowed to drive vehicles and engage in other potentially dangerous activities that require quick psychomotor reactions. During further treatment, the degree of restriction is determined according to the individual tolerability of prometazine.
Simultaneous use of promethazine potentiates the effect of opioid analgesics, hypnotics and local anaesthetics. Simultaneous use of promethazine with tricyclic antidepressants may increase the m-cholinoblocking effect as well as CNS depressant action; with antihypertensive drugs – possible increase in the effect of the latter.