Carbinoxamine Maleate

Pronunciation: car-bih-NOCK sah-meen MAL-ee-ate
Class: Ethanolamines, nonselective

Trade Names

Histex CT
- Tablets, timed-release 8 mg

Histex I/E
- Capsules, variable-release 2 mg/8 mg

Histex Pd
- Liquid 4 mg per 5 mL

Palgic
- Tablets 4 mg

Pediatex
- Liquid 1.75 mg per 5 mL

Pediatex 12
- Suspension 3.6 mg per 5 mL

Pharmacology

Competitively antagonizes histamine at H ₁ receptor sites.

Slideshow: Top Prevention Tips: Springtime Allergies

Pharmacokinetics

Elimination

The t _½ is 10 to 20 h. No intact drug is excreted in the urine.

Indications and Usage

Symptomatic treatment of nasal and nonnasal seasonal and perennial allergic rhinitis. Palgic tablets also are indicated for vasomotor rhinitis; allergic conjunctivitis caused by inhalant allergens and foods; mild, uncomplicated allergic skin manifestations of urticaria and angioedema; dermatographism; as therapy for anaphylactic reactions adjunctive to epinephrine and other standard measures after the acute manifestations have been controlled.

Contraindications

MAOI therapy; newborn or premature infants; lower respiratory tract symptoms, including asthma; breast-feeding mothers; hypersensitivity to any component of the product.

Dosage and Administration

PO 8 mg every 12 h.

PO 4 mg every 12 h.

Not recommended.

PO 1 capsule (2 mg/8 mg) every 12 h (max, 2 capsules in 24 h).

PO 5 mL (4 mg) 4 times daily.

PO 2.5 mL (2 mg) 4 times daily.

PO 1.25 to 2.5 mL (1 to 2 mg) 4 times daily.

PO 1 or 2 tablets (4 to 8 mg) 3 or 4 times daily.

PO 1 to 1½ tablets (4 to 6 mg) 3 or 4 times daily.

PO ½ to 1 tablet (2 to 4 mg) 3 or 4 times daily.

PO ½ tablet (2 mg) 3 or 4 times daily.

PO 10 mL (3.5 mg) 4 times daily.

PO 5 mL (1.75 mg) 4 times daily.

PO 3.75 to 5 mL (1.3 to 1.75 mg) 4 times daily.

PO 3.75 mL (1.3 mg) 4 times daily.

PO 2.5 mL (0.875 mg) 4 times daily.

PO 1.25 mL (0.44 mg) 4 times daily.

PO 10 to 20 mL (7.2 to 14.4 mg) every 12 h.

PO 5 to 10 mL (3.6 to 7.2 mg) every 12 h.

PO 2.5 to 5 mL (1.8 to 3.6 mg) every 12 h.

General Advice

• Administer without regard to meals. Administer with food if GI upset occurs.
• Timed-release tablets can be broken in half without affecting release of medication. Advise patient not to crush or chew tablets or half-tablets.
• Advise patient to swallow extended release capsule whole and not to crush, chew, or open the capsule.
• Shake oral suspension well before measuring dose. Measure and administer prescribed dose using dosing syringe, dosing spoon, or dosing cup.
• Use caution when administering oral liquid. Note that there are 2 concentrations (1.75 mg per 5 mL and 4 mg per 5 mL) available. Administering the wrong liquid can result in an overdose or underdose. Measure and administer prescribed dose using dosing syringe, dosing spoon, or dosing cup.

Storage/Stability

Store all dose forms at controlled room temperature (59° to 86°F). Protect oral suspension from freezing.

Drug Interactions

Effects may be enhanced by carbinoxamine.

May prolong and intensify the effects of carbinoxamine.

Laboratory Test Interactions

May interfere with diagnostic test results for skin tests using allergen extracts.

Adverse Reactions

CNS

Sedation; dizziness; headache; nervousness; nausea; anorexia; heartburn; weakness; disturbed coordination; excitability in children.

EENT

Diplopia.

GI

Vomiting; diarrhea; dry mouth; epigastric distress.

Genitourinary

Polyuria.

Respiratory

Thickening of bronchial secretions.

Precautions

Pregnancy

Category C .

Lactation

Contraindicated.

Concentrations

Ensure that orders for liquid carbinoxamine contain the concentration (1.75 mg per 5 mL or 4 mg per 5 mL) of the liquid to be administered.

Overdosage

Symptoms

In young children, predominant symptoms include the following: excitation, hallucination, ataxia, incoordination, tremors, flushed face, fever, convulsions, fixed and dilated pupils, coma, death. In adults, predominant symptoms include the following: fever, flushing, excitement, convulsions, postictal depression preceded by drowsiness and coma, respiratory depression.

Patient Information

• Advise patient to take each dose without regard to meals but to take with food if stomach upset occurs.
• Advise patient using immediate-release tablets to take prescribed dose 3 or 4 times daily as ordered.
• Advise patient using timed-release tablets to take prescribed dose every 12 h. Advise patient that timed-release tablet can be broken in half without affecting release of the medication but that tablets and half-tablets should not be crushed or chewed.
• Advise patient using extended-release capsules to take prescribed dose every 12 h. Caution patient to swallow capsules whole and not to crush, chew, or open the capsule.
• Advise patient or caregiver using oral suspension to administer prescribed dose every 12 h. Advise patient or caregiver to shake suspension well before measuring dose and to measure and administer prescribed dose using dosing syringe, dosing spoon, or dosing cup.
• Advise patient or caregiver using oral liquid to administer prescribed dose 4 times daily. Advise patient or caregiver to measure and administer prescribed dose using dosing syringe, dosing spoon, or dosing cup.
• Advise patient that if a dose is missed to take it as soon as possible unless it is nearing time for the next scheduled dose, then advise patient to skip the missed dose and take the next dose at the regularly scheduled time. Caution patient not to double the dose to catch up.
• Advise patient that if allergy symptoms are not controlled not to increase the dose of medication or frequency of use but to inform health care provider. Caution patient that larger doses or more frequent dosing does not increase effectiveness and may cause excessive drowsiness or other side effects.
• Instruct patient to stop taking drug and immediately report any of these symptoms to health care provider: persistent dizziness; excessive drowsiness; severe dry mouth, nose, or throat; flushing; unexplained shortness of breath or difficulty breathing; unusual tiredness or weakness; sore throat, fever, or other signs of infection; bleeding or unusual bruising; fast or irregular heartbeat; excitability, confusion, or changes in thinking or behavior; chest tightness; difficulty urinating.
• Advise patient that medication may cause drowsiness or dizziness and not to drive or perform other activities requiring mental alertness until tolerance is determined.
• Advise patient to take sips of water, suck on ice chips or sugarless hard candy, or chew sugarless gum if dry mouth occurs.
• Caution patient that alcohol and other CNS depressants (eg, sedatives) will have additional sedative effects if taken with carbinoxamine.
• Caution patient not to take any OTC antihistamines while taking this medication unless advised by health care provider.
• Caution patient that medication may cause sensitivity to sunlight and to avoid excessive exposure to the sun or UV light (eg, tanning booths) and to wear protective clothing and use sunscreens until tolerance is determined.
• If patient is to have allergy skin testing, advise patient not to take the medication for at least 4 days before the skin testing.

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