Ondansetron: Class, Trade Name:
Antiemetic, Ondansetron, Zofran
Antiemetic, 5-HT3 antagonist
Ondansetron Therapeutic Action/Mechanism:
Ondansetron is a selective 5-hydroxytryptamine subtype 3 (5-HT3) antagonist. The 5-HT3 receptor is located in central and peripheralnervous tissue, and on pre and post synaptic neurons. When agonized, anxiety, autonomic nerve activity and emesis occur.
Ondansetron Uses/ Indications:
Intractable Nausea and /or vomiting unrelieved by patient positioning
- Onset: 5 to 15 minutes IV.
- Peak effect 30 minutes IV
- Duration 4 – 8 hr
- Half-life: 3.5 – 5.5 hr (linear correlation to pt. age)
Ondansetron Contraindications/ Precautions:
Known sensitivity to ondansetron (Zofran), dolasetron (Anzemet) orpalonosetron (Aloxi).
- Caution with patients taking:
- Antiemetics: Granisetron, Tropisetron. Gastroprokinetics: Alosetron,Batanopride, Metoclopramide (high doses), Renzapride, Zacopride.
Antidepressants: Mianserin, Mirtazapine.
Antipsychotics: Clozapine,Olanzapine, Quetiapine. Others: Memantine (Alzheimer's diseasemedication). These may have additive effects.
Ondansetron Adverse/ Side Effects:
- CNS: Dizziness
- CV: hypotension, tachycardia, headache, bradycardia, heart block.Over dosage of up to 10 times the normal prescriptive amount has notdemonstrated significant adverse effects.
May have additive effects with other 5-HT3 receptor antagonists (see list above)
Ondansetron Adult Dosage:
4 mg IM, PO (dissolvable tablet) or slow IV (over 30 sec) for patients 4 years or older. May repeat with medical directionapproval.
Ondansetron Pediatric Dosage:
Not used for children under 4 years.
May be administered IM, IV or PO
Protect from light and heat. Pregnancy category B, doses of 4 mg/dayshow no adverse effects on fertility or fetal health
Oxygen Class, Trade Names:
Gas; Oxygen, Oxygen U.S.P.
Oxygen is an odorless, tasteless, colorless gas necessary for cellularmetabolic oxidative phosphorylation.
Oxygen Therapeutic Action/ Mechanism:
Oxygen is required for the efficient breakdown of glucose and othernutrient materials necessary for metabolism. Increased concentrationof oxygen in the alveolus subsequently leads to increased oxygensaturation of hemoglobin.
Hypoxia or suspected hypoxia. Oxygen is indicated in all forms oftrauma, medical emergencies, chest pain, respiratory difficulty,childbirth and for any critical patient
- Onset: Immediate.
- Peak effect in < 1 min.
- Duration < 2 min. following termination of delivery.
- Half-life: N/A
- No contraindications
- Oxygen should be used cautiously in patients with chronicobstructive pulmonary disease and in neonates. Prolonged highconcentrations of oxygen in these patients may be harmful.
Oxygen Adverse/Side Effects:
- CNS: None under normal barometric pressure
- CV: None
- Resp: Prolonged high flow oxygen without humidification may causedrying of mucus membranes. Use humidified oxygen when possible
- GI/GU: None
There are no interactions associated with oxygen administration,however, oxygen may increase the toxicity of certain herbicides suchas paraquat or diquat. Oxygen does support combustion and oxidation.
Oxygen Adult Dosage:
35% (COPD) - 100%
Oxygen Pediactric and Neonatal Dosage:
- Pediatric dose: Same as for adult.
- Neonatal dose: Not to exceed 40%
Nasal cannula (1-6 lpm - 24-44%), simple facemask(6-10 lpm - 40 – 60%),venturi mask (4-12 lpm - 24-50%), partialrebreather mask (6-10 lpm - 35-60%), non-rebreather mask (6-15 lpm -60 – 95%), BVM (with reservoir) (15 lpm - 40-90/100%)
Oxygen administration should be guided by oximetric measurementswhen possible, however, oxygen should not be withheld from dyspneic patients.