brompheniramine/dextromethorphan/phenylephrine (Neo DM Suspension, Dimaphen DM, Children's Dimetapp Cold and Cough)

Dosing and uses of Neo DM Suspension, Dimaphen DM (brompheniramine/dextromethorphan/phenylephrine)

• Adult
• Pediatric

 

Adult dosage forms and strengths

brompheniramine/dextromethorphan/phenylephrine

oral solution

• (1mg/5mg/2.5mg)/5mL

 

Relief of Cold Symptoms

4 teaspoons (20 mL) PO q4hr; not to exceed 120 mL/24 hr

 

Pediatric dosage forms and strengths

brompheniramine/dextromethorphan/phenylephrine

oral solution

• (1mg/5mg/2.5mg)/5mL

 

Relief of Cold Symptoms

<6 years

• Not recommended

6-12 years

• 2 teaspoons (10 mL) PO q4hr

>12 years

• 4 teaspoons (20 mL) PO q4hr

 

Neo DM Suspension, Dimaphen DM (brompheniramine/dextromethorphan/phenylephrine) adverse (side) effects

Frequency not defined

Dizziness

Drowsiness

Dry mouth, throat, and nose

Thickening of mucus in nose or throat GI disturbances

Reflex tachycardia

Excitability

Restlessness

Headache

Hypertension

Severe peripheral and visceral vasoconstriction

 

Warnings

Contraindications

Hypersensitivity

Asthma

< 2 years of age

Severe hypertension

Narrow-angle glaucoma

Symptomatic prostate hypertrophy

Bladder-neck obstruction

Stenosing peptic ulcer

Use within 14 days of MAO inhibitor therapy

 

Cautions

Brompheniramine: May cause significant confusional symptoms; not for administration to premature or full-term neonates

Dextromethorphan: Do not take for persistent or chronic cough associated with smoking, asthma, or emphysema, or if it is accompanied by excessive phlegm unless directed by a healthcare provider; may decrease respiration rate

Phenylephrine: Caution in elderly patients, hyperthyroidism, myocardial disease, bradycardia, partial heart block or severe arteriosclerosis

 

Pregnancy and lactation

Pregnancy category: C

Lactation: excreted in breast milk; use caution

Pregnant or breastfeeding patients should seek advice of health professional before using OTC drugs

 

Pregnancy categories

A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

NA: Information not available.

 

Pharmacology of Neo DM Suspension, Dimaphen DM (brompheniramine/dextromethorphan/phenylephrine)

Mechanism of action

Brompheniramine: Competitively blocks histamine from binding to H1 receptors; significant antimuscarinic activity and penetrates CNS, which causes pronounced tendency to induce sedation

Dextromethorphan: Cough suppressant that acts centrally on the cough center in medulla

Phenylephrine: Vasoconstrictor & decongestant that relieves symptoms resulting from irritation of upper respiratory tract tissue; shrinks swollen mucous membranes, reduces nasal congestion and tissue hyperemia

 

Pharmacokinetics

Brompheniramine

• Onset: 15-30 min
• Duration: 3-9 hr, may last 48 hr
• Peak Plasma Time: 2-5 hr
• Vd: 11.7 L/kg (adults); 20 L/kg (children)
• Protein binding: 39-49%
• Metabolism: Mainly liver; metabolites include propionic acid derivative conjugated with glycine
• Half-Life: 11.8 (children); 25 hr (adults)
• Excretion: Urine

Dextromethorphan

• Onset: 15-30 min
• Duration: 3-6 hr
• Metabolism: Hepatic P450 enzyme CYP2D6
• Excretion: Urine
• Half-life: 2-4 hr (extensive metabolizers); 24 hr (poor metabolizers)
• Peak plasma time: 2-3 hr

Phenylephrine

• Half-life: 2-3 hr
• Onset: 10-15 min
• Duration: 15 min
• Bioavailability: < 38%
• Excretion: Urine (80-90%)
• Peak plasma time: 0.75-2 hr
• Vd: 26-61 L
• Vdss: 340 L