What precautions should be taken when prescribing brompheniramine-pseudoephedrine (Brompheniramine-Pseudoephedrine DM)?

Precautions for Brompheniramine-Pseudoephedrine DM

Exercise caution when prescribing brompheniramine-pseudoephedrine DM in patients with cardiovascular disease, hypertension, narrow-angle glaucoma, urinary obstruction, or those taking MAO inhibitors, as the combination contains both an antihistamine and sympathomimetic that can cause serious adverse effects in these populations. 1

Absolute Contraindications

MAO Inhibitor Use

• Never prescribe this combination to patients taking MAO inhibitors - concomitant use can cause hyperpyrexia, hypotension, and death due to interactions with dextromethorphan, plus prolonged anticholinergic effects from the antihistamine and enhanced sympathomimetic effects from pseudoephedrine 1, 2
• MAO inhibitors must be discontinued for at least 14 days before initiating this medication 2

Nursing Mothers

• This medication is contraindicated in nursing mothers due to higher risk of antihistamine intolerance in small infants, particularly newborns and premature infants 1

High-Risk Populations Requiring Extreme Caution

Cardiovascular Disease Patients

• Use with extreme caution in patients with hypertension, arrhythmias, coronary artery disease, or cerebrovascular disease due to the pseudoephedrine component's α-adrenergic agonist effects 1, 3, 4
• Pseudoephedrine increases systolic blood pressure by approximately 1 mmHg and heart rate by 2.83 beats/min on average, though individual responses vary 3
• Patients with uncontrolled hypertension should avoid this medication entirely; consider alternative therapies such as intranasal corticosteroids or antihistamines without decongestants 3, 5
• Even patients with controlled hypertension require blood pressure monitoring during treatment 3, 6

Patients with Specific Medical Conditions

• Narrow-angle glaucoma: The antihistamine component can worsen this condition 1
• Urinary bladder neck obstruction: Anticholinergic effects can cause urinary retention 1
• Gastrointestinal obstruction: Anticholinergic effects may worsen obstruction 1
• Bronchial asthma: Use cautiously due to antihistamine effects 1
• Diabetes mellitus: Sympathomimetic component requires caution 1
• Thyroid disease/hyperthyroidism: Sympathomimetic effects can exacerbate thyroid conditions 1, 4

Drug Interactions to Avoid

CNS Depressants

• Antihistamines have additive effects with alcohol, hypnotics, sedatives, tranquilizers, and antianxiety agents 1
• Warn patients about enhanced sedation and impaired mental alertness 1

Antihypertensive Medications

• Sympathomimetics may reduce the effectiveness of antihypertensive drugs 1
• Monitor blood pressure closely if concurrent use is necessary 3

Multiple Decongestants

• Never combine with other sympathomimetic decongestants (oral or topical) as this can lead to hypertensive crisis due to combined vasoconstrictive effects 3, 5

Caffeine

• Concomitant caffeine use produces additive adverse effects including elevated blood pressure, insomnia, irritability, and palpitations 3, 4

Age-Related Precautions

Pediatric Patients

• Safety and effectiveness not established in children under 6 months of age 1
• Use appropriate weight-based dosing in older children 1

Geriatric Patients

• Elderly patients are at higher risk for dizziness, sedation, hypotension, and adverse reactions to sympathomimetics 1
• Start at the low end of the dosing range due to decreased hepatic, renal, or cardiac function 1
• Increased risk of falls due to antihistamine effects 7

Activities Requiring Mental Alertness

• Warn patients explicitly about impaired ability to drive or operate dangerous machinery due to antihistamine-induced sedation 1
• This warning applies even if patients do not feel subjectively drowsy 1

Pregnancy Considerations

• Pregnancy Category C: No adequate human studies exist 1
• Should only be given to pregnant women if clearly needed, as fetal harm cannot be ruled out 1

Monitoring Recommendations

• Monitor blood pressure in all patients with cardiovascular risk factors or hypertension 3
• Recheck blood pressure 24-48 hours after discontinuation if hypertension develops 3
• Watch for urinary retention, particularly in elderly males 1, 8
• Monitor for sleep disturbances, which are common side effects 8

Common Pitfalls to Avoid

• Do not assume "controlled" hypertension means the medication is completely safe - individual responses vary and monitoring is still required 3, 6
• Do not overlook over-the-counter medications that patients may be taking, particularly other decongestants or caffeine-containing products 3, 2
• Do not prescribe for extended periods without reassessing need, as sympathomimetics should be used for the shortest duration possible 5