Granisetron

INTRODUCTION

Indications

Prevention of nausea and vomiting due to: emetogenic chemotherapy, radiation therapy. Prevention and treatment of postoperative nausea and vomiting.

Action

Blocks the effects of serotonin at receptor sites (selective antagonist) located in vagal nerve terminals and in the chemoreceptor trigger zone in the CNS. Therapeutic Effects: Decreased incidence and severity of nausea and vomiting following emetogenic chemotherapy, radiation therapy, or surgery.

Adverse Reactions/Side Effects

CNS: headache, agitation, anxiety, CNS stimulation, drowsiness, weakness. CV: hypertension. GI: constipation, diarrhea, elevated liver enzymes, taste disorder. Derm: application-site reactions, photosensitivity. Misc: anaphylactoid reactions, fever.

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Monitor improvements in GI symptoms (decreased nausea and vomiting, increased appetite) to help document whether drug therapy is successful.

• Monitor signs of allergic and anaphylactoid reactions, including pulmonary symptoms (tightness in the throat and chest, wheezing, cough, dyspnea) or skin reactions (rash, pruritus, urticaria). Notify physician or nursing staff immediately if these reactions occur.

• Assess blood pressure (BP) and compare to normal values (See Appendix F). Report a sustained increase in BP (hypertension).

• Monitor personality changes, including agitation, anxiety, or other signs of CNS excitation. Notify physician if these changes become problematic.

• If applied transdermally, monitor the application site for local irritation or inflammation. Report excessive application-site reactions to the physician.

Patient/Client-Related Instruction

• Instruct patient to report bothersome side effects such as severe or prolonged headache, drowsiness, weakness, fever, or GI problems (diarrhea, constipation, abnormal taste).

Pharmacokinetics

Absorption: 50% absorbed following oral administration.

Distribution: Distributes into erythrocytes; remainder of distribution is unknown.

Metabolism and Excretion: Mostly metabolized by the liver; 12% excreted unchanged in urine.

Half-life: Patients with cancer—8–9 hr (range 0.9–31.1 hr); healthy volunteers —4.9 hr (range 0.9–15.2 hr); geriatric patients—7.7 hr (range 2.6–17.7 hr).

Contraindications/Precautions

Contraindicated in: Hypersensitivity; Some products contain benzyl alcohol; avoid use in neonates.

Use Cautiously in: OB/Lactation: Safety not established; Pedi: Children <2 yr (safe use of IV route not established); Pedi: Children <18 yr (safe use of PO route not established).

Interactions

Drug-Drug: ↑ risk of extrapyramidal reactions with other agents causing extrapyramidal reactions.

Route/Dosage

Prevention of Nausea ...