antihistamine

phenothiazine

• H₁ receptor antagonist (blocks actions of histamine by comp. antag. at H₁ receptor)
• sedative, antimotion, antiemetic, anticholinergic effects
• often admin. w/ analgesics (particularly narc.s) to potentiate their effects (controversial)

Onset - IV rapid

Duration - 4-6 hr

• N+V
• motion sickness
• pre- and post-op, OB (during labor) sedation
• to potentiate effects of analgesics
• allergic rxns

• hypersensitivity
• comatose states
• CNS depression for EtOH, barbituates, narc.s
• signs assoc. w/ Reye's syndrome

• sedation
• dizziness
• may impair mental and physical ability
• allergic rxns
• dysrythmias
• N+V
• hyperexcitability
• dystonias
• in peds - may cause hallucinations, convulsions and sudden death

• CNS depressants - concomitant use may have additive sedative effects
• MAOIs - increased incidence of extrapyramidal effects
• Epinephrine - concomitant use may decrease BP further

Promethazine - Dosage and Admin.

Adult

Promethazine - Dosage and Admin

Pediatric

• Preg - C (generally considered safe for use during labor)
• caution in pts w/ asthma, peptic ulcer, and bone marrow depression
• take care to avoid accidental intraarterial injection
• IM preferred
• give slow IV over 1 min, dilute in 10-20 ml NS, use port farthest from vein and stop i pt complains of pain

Extrapyramidal system: neural network in brain, part of motor system, involved in coordination

akinesia: inability to initiate movement

akathisia: inability to remain motionless