proe-METH-a-zeen
Therapeutic Classification: antiemetics, antihistamines, sedative/hypnotics
Pharmacologic Classification: phenothiazines
BEERS REMS, High Alert
Absorption: Well absorbed after oral (88%) and IM administration; rectal administration may be less reliable. IV administration results in complete bioavailability.
Distribution: Widely distributed to tissues.
Half-Life: 9–16 hr.
(noted as antihistaminic effects; sedative effects last 2–8 hr)
| ROUTE | ONSET | PEAK | DURATION |
|---|---|---|---|
| PO, IM | 20 min | unknown | 4–12 hr |
| Rectal | 20 min | unknown | 4–12 hr |
| IV | 3–5 min | unknown | 4–12 hr |
Contraindicated in:
Children <2 yr (may cause fatal respiratory depression)
.Use Cautiously in:
Children >2 yr (use lowest effective dose and avoid concurrent respiratory depressants)
;CV: bradycardia, hypertension, hypotension, tachycardia
Derm: photosensitivity, rash, severe tissue necrosis upon infiltration at IV site
EENT: blurred vision, diplopia, tinnitus
GI: constipation, dry mouth, hepatitis
Hemat: blood dyscrasias
Neuro: confusion, disorientation, sedation, dizziness, extrapyramidal reactions, fatigue, insomnia, nervousness, NEUROLEPTIC MALIGNANT SYNDROME
Drug-drug:
Antihistamine
Antivertigo (Motion Sickness)
Sedation
Lab Test Considerations:
Administer deep into well-developed muscle. SUBQ or inadvertent intra-arterial administration may cause severe tissue necrosis and is contraindicated.
IV Administration:
If administered IV, assess for burning and pain at IV site; may cause severe tissue injury. Avoid IV administration, if possible. Administer IV only if IM injection not possible. If pain occurs after IV administration, discontinue administration immediately and evaluate for possible arterial injection or perivascular extravasation, and initiate appropriate medical management.
IV promethazine is a vesicant. Dilution is required before administering IV. Administer into a large vein or preferably through a central venous catheter. If extravasation occurs, immediately stop infusion. Leave needle/cannula in place temporarily but do not flush the line. Gently aspirate extravasated solution; then remove needle/cannula. Elevate patient's extremity and apply dry warm or dry cold compresses. Initiate hyaluronidase antidote for refractory cases in addition to supportive management. For hyaluronidase, inject a total of 1 mL (15 units/mL) intradermally or SUBQ as five separate 0.2-mL injections (using a tuberculin syringe) around the site of extravasation; if IV catheter remains in place, administer IV through the infiltrated catheter; may repeat in 30–60 min if no resolution.