Antiemetics

Section 8 - MEDICATION GUIDELINES

8.09 ANTIEMETICS

Promethazine (PHENERGAN) / Antiemetic

DESCRIPTION:

• Blocks cholinergic receptors in the vomiting center, which may mediate nausea and vomiting; competes with histamine for the H1 receptor site.

ACTION:

• Blocks the effects of the hormone serotonin at the 5-HT3 -receptor sites (located in the vagal nerve terminals) that cause vomiting.
• Half-life 3.5 - 5.5 hr

INDICATIONS:

• Severe, persistent vomiting.

CONTRAINDICATIONS:

• Coma, CNS depression, seizures, known hypersensitivity to drug

PRECAUTIONS:

• Get as complete a history as possible before administering.
• Using with epinephrine may result in further hypotension.
• Using with barbiturates, tranquilizers, or alcohol may further CNS depression
• FDA MANDATED BLACK BOX WARNING: If this medication is administered incorrectly it can cause severe skin damage up to and including gangrene. This damage may lead to amputation of the affected limb.

DOSAGE:

• Currently supplied in 25 mg/ml vial
• Adult (>13 y/o): 12.5 mg slow IVP, or IM.
  • Dilution is not necessary when given IM
  • IV site must be checked for patency before infusing the medication – document patent flow of the IV site on the patient care report
  • MUST be diluted in a minimum of 10 ml of normal saline when given IV
  • MUST be given through an IV line actively infusing fluids
• Pediatric: .25-1mg/kg slow IVP, or IM.
  • Dilution is required as noted above.
  • The maximum single dose to be given must not exceed 12.5 mg

BLACK BOX WARNING The IV (perenteral) administration of PHENERGAN (PROMETHAZINE) has a RELATIVE CONTRAINDICATION in children under 2 years of age. The provider must weigh the risk vs. benefit of PHENERGAN (PROMETHAZINE) administration based on the patient's condition.

Ondansetron Hydrochloride (ZOFRAN) / Antiemetic

DESCRIPTION:

• This medication is used to prevent or decrease the severity of nausea and vomiting.

ACTION:

• Blocks the effects of the hormone serotonin at the 5-HT3 -receptor sites (located in the vagal nerve terminals) that cause vomiting.
• Half-life 3.5 - 5.5 hr

INDICATIONS:

• Severe, persistent vomiting.

CONTRAINDICATIONS:

• Known hypersensitivity.

PRECAUTIONS:

• Patients with liver impairment
• Pregnancy-Category B- Studies have revealed no evidence of impaired fertility or harm to the fetus.
• May cause an extrapyramidal reaction.
• Little information is available about dosage in pediatric patients under 2 years of age.

DOSAGE:

• Currently supplied in 4mg/2ml vials and 4 mg oral disintegrating tablets (ODT)
• Adult: 4mg slow IVP or 1 ODT tab.
  • When administering IV, consider diluting in 10-20 ml normal saline to aid in administering slowly or 4mg/2ml deep IM in a large muscle.
• Pediatrics:
  • Premie - 8 years old - ADMINISTER 0.15 mg/kg slow IVP (mag of 4 mg)
  • 9 years and older - 4 mg slow IVP
  • For PO administration:
    • 1-3 year old – ADMINISTER ½ ODT tab
    • 4 years and older: ADMINISTER 1 ODT tab
• NOTE: Use PO administration route for conscious patients ONLY.