Teldrin

Action

Antagonizes effects of histamine at histamine₂-receptor sites, preventing histamine-mediated responses

Availability

Capsules (sustained-release): 8 mg, 12 mg

Syrup: 1 mg/5 ml, 2 mg/5 ml, 2.5 mg/5 ml

Tablets: 4 mg, 8 mg, 12 mg

Tablets (chewable): 2 mg

Tablets (timed-release): 8 mg, 12 mg

Indications and dosages

➣ Allergy symptoms; management of anaphylaxis and transfusion reactions

Adults: 4 mg q 4 to 6 hours P.O. or 8 to 12 mg P.O. of sustained-release form q 8 to 12 hours. Maximum dosage is 24 mg/day.

Children ages 6 to 12: 2 mg P.O. q 4 to 6 hours daily. Maximum dosage is 12 mg/day.

Dosage adjustment

• Glaucoma

• Gastric ulcer

• Hyperthyroidism

• Heart disease

Contraindications

• Hypersensitivity to drug

• Acute asthma attacks

• Stenosing peptic ulcer

• Breastfeeding

Precautions

Use cautiously in:

• hepatic or renal disease, asthma, angle-closure glaucoma, prostatic hypertrophy

• elderly patients

• pregnant patients (safety not established).

Administration

• Don't crush or break timed-release tablets or sustained-release capsules.

• Discontinue drug 4 days before allergy skin tests. (Drug may cause false-negative reactions.)

Adverse reactions

CNS: dizziness, drowsiness, excitation (in children), sedation, poor coordination, fatigue, confusion, restlessness, nervousness, tremor, headache, hysteria, tingling sensation, sensation of heaviness and weakness in hands

CV: palpitations, hypotension, bradycardia, tachycardia, extrasystoles, arrhythmias

EENT: blurred vision, diplopia, vertigo, tinnitus, acute labyrinthitis, nasal congestion, dry nose, dry throat, sore throat

GI: nausea, vomiting, diarrhea, constipation, epigastric distress, anorexia, dry mouth, GI obstruction

GU: urinary retention, urinary hesitancy, dysuria, early menses, decreased libido, erectile dysfunction

Hematologic: hemolytic anemia, hypoplastic anemia, thrombocytopenia, leukopenia, pancytopenia, agranulocytosis

Respiratory: thickened bronchial secretions, chest tightness, wheezing

Skin: urticaria, rash, photosensitivity, diaphoresis

Other: chills, increased appetite, weight gain, anaphylactic shock

Interactions

Drug-drug. Anticholinergics, anti-cholinergic-like drugs (such as some antidepressants, atropine, haloperidol, phenothiazines, quinidine, disopyramide): additive anticholinergic effects

CNS depressants (such as opioids, sedative-hypnotics): additive CNS depression

MAO inhibitors: intensified, prolonged anticholinergic effects

Drug-diagnostic tests. Allergy skin tests: false-negative reactions

Drug-behaviors. Alcohol use: additive CNS depression

Sun exposure: photosensitivity

Patient monitoring

• Assess for urinary retention and frequency.

• Monitor respiratory status throughout therapy.

Patient teaching

• Advise patient to take with full glass of water.

• Tell patient not to crush timed-release tablets or sustained-release capsules. Instruct him to swallow them whole.

• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.

• Advise parents to give dose to children in evening, because morning doses may cause inattention in school.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, and behaviors mentioned above.