General

Pronunciation:
car-bi-nox-a-meen

Trade Name(s)

• Carbzah
• Karbinal ER
• Ryvent

Ther. Class.

allergy, cold and cough remedies

Pharm. Class.

antihistamines

Indications

• Seasonal and perennial allergic rhinitis.
• Vasomotor rhinitis.
• Allergic conjunctivitis due to inhalant allergens and foods.
• Mild, uncomplicated allergic skin manifestations of urticaria and angioedema.
• Dermatographism.
• Anaphylaxis (as adjunct to epinephrine after acute manifestations controlled).
• Allergic reactions to blood or plasma.

Action

Antagonizes the effects of histamine at H_1- receptor sites; does not bind to or inactivate histamine. Significant CNS depressant and anticholinergic properties.

Therapeutic Effect(s):

Decreased symptoms of histamine excess (sneezing, rhinorrhea, nasal/ocular pruritus, ocular tearing/redness and skin itching/urticaria).

Pharmacokinetics

Absorption: Well absorbed following oral administration.

Distribution: Unknown.

Metabolism and Excretion: Extensively metabolized by the liver. Inactive metabolites excreted in urine; Negligible renal elimination of unchanged drug.

Half-life: 17 hr

TIME/ACTION PROFILE (plasma concentrations)

Contraindication/Precautions

Contraindicated in:

• Hypersensitivity, including sulfite allergy
• Lactation: Lactation;
• Pedi:  Children <2 yr (↑ risk of death).

Use Cautiously in:

• ↑ intraocular pressure or narrow angle glaucoma
• Hyperthyroidism
• Cardiovascular disease, including hypertension
• Stenosing peptic ulcer or pyloroduodenal obstruction
• Symptomatic prostatic hypertrophy or bladder neck obstruction
• OB:  Safety not established in pregnancy;
• Pedi:  Younger children may be more sensitive to sedation or excitation;
• Geri:  Older adults may be more susceptible to adverse reactions.

Adverse Reactions/Side Effects

GI: epigastric distress

Neuro: disturbed coordination, dizziness, drowsiness, sedation

Resp: thickened bronchial secretions

* CAPITALS indicate life-threatening.
Underline indicate most frequent.

Interactions

Drug-Drug

•  MAO inhibitors  may ↑ anticholinergic effects.
• ↑ risk of CNS depression with other  CNS depressants  including  alcohol, other  antihistamines,  opioid analgesics, and  sedative/hypnotics.

Route/Dosage

PO (Adults and Children  ≥ 12 yr): Immediate-release tablets or solution: 4–8 mg 3–4 times daily;  Extended-release suspension: 6–16 mg every 12 hr.

PO (Children  6–11 yr): Immediate-release tablets or solution: 2–4 mg 3–4 times daily;  Extended-release suspension: 6–12 mg every 12 hr.

PO (Children  4–5 yr): Immediate-release solution: 1–2 mg 3–4 times daily;  Extended-release suspension: 3–8 mg every 12 hr.

PO (Children  2–3 yr): Immediate-release solution: 1–2 mg 3–4 times daily;  Extended-release suspension: 3–4 mg every 12 hr.

Availability (generic available)

Immediate-release tablets: 4 mg, 6 mg

Immediate-release oral solution (banana bubble gum flavor): 4 mg/5 mL

Extended-release oral suspension (contains metabisulfite) (strawberry banana flavor): 4 mg/5 mL

Assessment

• Assess allergy symptoms (rhinitis, conjunctivitis, hives) before and periodically during therapy.
• Assess lung sounds and character of bronchial secretions. Maintain fluid intake of 1,500–2,000 mL/day to ↓ viscosity of secretions.
• Monitor for allergic reaction (anaphylaxis, reactive airway) especially in patients with asthma using oral suspension containing sodium metabisulfite.

Lab Test Considerations:

May ↑ uric acid levels.

Implementation

• Begin with lowest dose and ↑ as needed and tolerated. Dose is based on condition severity and response.
• PO Administer twice daily.
  • Use a calibrated measuring device for accurate dose; household tablespoon is not accurate and could lead to overdose. May be fatal if administered to children <2 yr. Shake well before using.

Patient/Family Teaching

• Explain purpose and side effects of medication. Advise patient to read  Patient Information  before starting therapy.
• Advise patient to notify health care provider of all Rx or OTC medications, vitamins, or herbal products being taken and to consult health care provider before taking other medications.
• Advise patient to avoid taking alcohol or other CNS depressants concurrently with this drug, may cause overdose.
• May cause dizziness and drowsiness. Caution patient to avoid driving or other activities requiring alertness until response to medication is known
• Advise patient that good oral hygiene, frequent rinsing of mouth with water, and sugarless gum or candy may minimize dry mouth. Patient should notify dentist if dry mouth persists >2 wk
• Advise patient to notify health care provider if they have ↑ intraocular pressure, narrow angle glaucoma, hyperthyroidism, cardiovascular disease, hypertension, peptic ulcer, prostatic hypertrophy, or bladder neck obstruction.
• Rep:  Instruct women of reproductive potential to notify health care provider if pregnancy is planned or suspected and avoid breastfeeding during therapy.

Evaluation/Desired Outcomes

Decrease in allergic symptoms.