Hydroxyzinum Pph (Hydroxyzine Hydrochloride)

Hydroxyzinum Pph is a first‑generation antihistamine that acts on histamine‑mediated skin and central nervous system pathways.

• Allergic skin conditions (e.g., dermatitis, urticaria): reduces itching, erythema and rash.
• Pruritus: alleviates persistent itching associated with dermatologic disorders.
• Anxiety: provides short‑term anxiolytic and sedative effects, especially useful for pre‑operative calming.

• Hydroxyzine hydrochloride selectively blocks peripheral histamine H1 receptors, preventing histamine‑induced vasodilation and increased vascular permeability. It also exhibits anticholinergic activity and penetrates the central nervous system, where it produces sedative and anxiolytic effects by inhibiting neuronal excitation. The combined peripheral and central actions account for its antipruritic and calming properties.

Hydroxyzinum Pph may cause a range of adverse reactions, most of which are dose‑related and reversible.

Common Side Effects

• Drowsiness: feeling of sleepiness or reduced alertness.
• Dry mouth: decreased salivation leading to a sticky sensation.
• Blurred vision: temporary difficulty focusing.
• Constipation: reduced bowel motility.
• Dizziness: sensation of light‑headedness.
• Headache: mild to moderate cranial pain.

Serious or Rare Side Effects

• Cardiac arrhythmia: irregular heart rhythm, especially in patients with pre‑existing conditions.
• Severe skin reactions: such as Stevens‑Johnson syndrome or toxic epidermal necrolysis.
• Seizures: rare occurrence of convulsive episodes.
• Hepatotoxicity: abnormal liver function tests or liver injury.
• Hemolytic anemia: destruction of red blood cells.
• Neuroleptic malignant‑like syndrome: rare, potentially life‑threatening reaction with high fever and muscle rigidity.

Before prescribing Hydroxyzinum Pph, clinicians should consider several safety factors.

• Pregnancy: limited data; use only if potential benefit justifies potential risk.
• Elderly: increased sensitivity to sedation and anticholinergic effects; start with lower doses.
• Driving: advise patients not to operate machinery until they know how the drug affects them.
• Concomitant CNS depressants: may enhance drowsiness and respiratory depression.
• Renal or hepatic impairment: dose adjustment may be necessary due to altered clearance.
• Store at ambient temperature: keep in the original container, protect from moisture and light.

Hydroxyzinum Pph can interact with several medication classes, altering its safety or efficacy.

Major Interactions (Avoid)

• Alcohol: additive central nervous system depression leading to profound sedation.
• Opioids: synergistic respiratory depression and excessive drowsiness.
• Anticholinergic drugs: cumulative anticholinergic burden may cause severe dry mouth, urinary retention, or confusion.
• QT‑prolonging agents: increased risk of cardiac arrhythmias.

Moderate Interactions (Monitor Closely)

• CYP3A4 inhibitors (e.g., erythromycin, ketoconazole): may raise hydroxyzine plasma concentrations.
• CYP3A4 inducers (e.g., rifampin, carbamazepine): may reduce therapeutic effect.
• Antidepressants (e.g., SSRIs, TCAs): potential additive QT‑prolongation risk.