Hydroxyzine
Mechanism :
Hydroxyzine is not a cortical depressant, but its action may be due to a suppression of activity in certain key regions of the subcortical area of the central nervous system. Primary skeletal muscle relaxation has been demonstrated experimentally. Bronchodilator activity, and anti-histaminic and analgesic effects have been demonstrated experimentally and confirmed clinically.
Indication :
- Urticaria
- Pruritus
- Anxiety- short term
- Nausea and vomiting
- Adjunct to anaesthesia/Preoperative sedation
Contraindications :
Hydroxyzine is contraindicated for patients who have shown a previous hypersensitivity to it and in early pregnancy. Use with caution in patients with impaired renal function since it is uncertain whether the drug may accumulate or have other adverse effects in such patients. Avoid in patients with acute porphyria.
Dosing :
Pruritis, nausea, vomiting:
<6 years of age;
50 mg/day in four divided oral doses.
>6 years of age:
50-100 mg in four divided oral doses.
Preoperative sedation:
0.6 mg/kg given orally or 0.5-1.1 mg/kg IM.
Adverse Effect :
Drowsiness, dry mouth, weakness, headache, dizziness, confusion, tremor and convulsions.
Interaction :
Narcotics, Non-Narcotic Analgesics and Barbiturates: Potentiating action of hydroxyzine must be considered. Therefore, when central nervous system depressants are administered concomitantly with hydroxyzine their dosage should be reduced.
Renal Dose :
Dose in Renal Impairment GFR (mL/min)
| 20-50 | Dose as in normal renal function |
| 10-20 | Start with small dose, e.g. 25 mg at night and increase to 2–3 times a day if necessary |
| <10 | Start with small dose, e.g. 25 mg at night and increase to 2–3 times a day if necessary |
Dose in Patients undergoing Renal Replacement Therapies
| CAPD | Not dialysed. Dose as in GFR<10 mL/min |
| HD | Not dialysed. Dose as in GFR<10 mL/min |
| HDF/High flux | Not dialysed. Dose as in GFR<10 mL/min |
| CAV/VVHD | Not dialysed. Dose as in GFR=10– 20 mL/min |
Hepatic Dose :
Mild – Moderate hepatic impairment: The total daily dose should be reduced by one-third.
Severe hepatic impairment: Avoid use.