Is phenylpropanolamine combined with brompheniramine contraindicated in patients with glaucoma, especially narrow‑angle (acute) glaucoma?

Phenylpropanolamine + Brompheniramine is Contraindicated in Narrow-Angle Glaucoma

Yes, the combination of phenylpropanolamine (a sympathomimetic decongestant) and brompheniramine (an antihistamine with anticholinergic properties) is contraindicated in patients with narrow-angle (acute angle-closure) glaucoma, but NOT in patients with open-angle glaucoma. 1, 2

Understanding the Mechanism of Risk

Anticholinergic Effects from Brompheniramine

• Brompheniramine, as an antihistamine with anticholinergic properties, can precipitate acute angle closure through pupillary dilation in patients with anatomically narrow anterior chamber angles 3, 1
• The anticholinergic effect causes mid-pupillary dilation that bunches peripheral iris tissue into the angle, blocking aqueous humor outflow 3
• This mechanism poses particular risk in hyperopic, older phakic patients with shallow anterior chambers 3, 1

Sympathomimetic Effects from Phenylpropanolamine

• Phenylpropanolamine, as an adrenergic agonist, can trigger acute angle closure glaucoma through mydriasis (pupil dilation) in predisposed individuals with narrow angles 1, 4
• Adrenergic agents work locally or systemically to cause pupillary block, which is treatable by peripheral iridotomy 1

Combined Risk Profile

• Both components work through similar pupillary block mechanisms, making the combination particularly hazardous in patients with narrow angles 1, 2
• The risk is specifically for angle-closure glaucoma, NOT open-angle glaucoma 2

Clinical Decision Algorithm

Step 1: Identify the Type of Glaucoma

• If narrow-angle (angle-closure) glaucoma or anatomically narrow angles: Absolute contraindication—do not prescribe 1, 4
• If open-angle glaucoma: Generally safe to use; these medications do not worsen open-angle glaucoma 2
• If glaucoma type unknown: Obtain ophthalmologic evaluation with gonioscopy before prescribing 3

Step 2: Assess Anatomical Risk Factors

Even without diagnosed glaucoma, avoid this combination in patients with: 4

• Shallow anterior chamber depth
• Short axial length
• Hyperopia (farsightedness)
• Female sex, Asian ethnicity, advanced age
• Family history of angle-closure glaucoma

Step 3: Consider Prophylactic Measures

• If narrow angles are confirmed but medication is deemed necessary, consider prophylactic laser peripheral iridotomy before initiating therapy 3
• Ophthalmologic evaluation should precede any consideration of this combination in at-risk patients 3

Warning Signs to Monitor

Educate patients to seek immediate care if they develop: 3, 4

• Sudden eye pain
• Severe headache with nausea
• Blurred vision or halos around lights
• Red eye with decreased vision

Common Pitfalls to Avoid

• Do not assume all glaucoma is the same: The contraindication applies specifically to narrow-angle glaucoma, not open-angle glaucoma 2
• Do not rely solely on patient history: Many individuals with narrow angles are unaware of their anatomical predisposition until an acute attack occurs 1
• Do not confuse mechanism with topiramate: While topiramate also causes angle closure, it works through ciliary body edema rather than pupillary block, representing a completely different mechanism 3
• Do not overlook the package insert warning: Although product labeling may mention "glaucoma" as a contraindication without specifying type, clinicians must understand this refers to angle-closure glaucoma 2

Alternative Considerations

For patients with narrow-angle glaucoma requiring treatment for rhinosinusitis or allergic symptoms:

• One study in children with acute rhinosinusitis found that adding brompheniramine and phenylpropanolamine to antibiotics provided no additional benefit over antibiotics alone 5
• This suggests the combination may be unnecessary in many clinical scenarios, making the risk-benefit calculation favor avoidance in at-risk patients 5