DrugindexOnline^{2nd edition}

Pronouncation: (Fen-ill-EFF-rin HIGH-droe-KLOR-ide /GWHY-fen-ah-sin)
Class: Decongestant, Expectorant

Trade Names:
Rescon-GG
- Liquid 5 mg phenylephrine hydrochloride and 100 mg guaifenesin

Trade Names:
Entex
- Liquid 7.5 mg phenylephrine hydrochloride and 100 mg guaifenesin

Trade Names:
Guaifed-PD
- Capsules 7.5 mg phenylephrine hydrochloride and 200 mg guaifenesin

Trade Names:
Entex ER
- Capsules, extended-release 10 mg phenylephrine hydrochloride and 300 mg guaifenesin

Trade Names:
Guaifed
- Capsules 15 mg phenylephrine hydrochloride and 400 mg guaifenesin

Trade Names:
SINUvent PE
- Tablets 15 mg phenylephrine hydrochloride and 600 mg guaifenesin

Trade Names:
GFN 600/Phenylephrine 20
- Tablets 20 mg phenylephrine hydrochloride and 600 mg guaifenesin

Trade Names:
Liquibid-PD
- Tablets, extended-release 20 mg phenylephrine hydrochloride and 315 mg guaifenesin

Trade Names:
Entex LA
- Capsules, extended-release 30 mg phenylephrine hydrochloride and 600 mg guaifenesin

Trade Names:
Liquibid-D
- Tablets, extended-release 40 mg phenylephrine hydrochloride and 650 mg guaifenesin

Trade Names:
Liquibid-D 1200
- Tablets, extended-release 40 mg phenylephrine hydrochloride and 1,200 mg guaifenesin

Mechanism of Action

Pharmacology

Phenylephrine

Stimulates postsynaptic alpha-receptors, resulting in vasoconstriction, which reduces congestion.

Guaifenesin

May enhance output of respiratory tract fluid by reducing adhesiveness and surface tension, enhancing removal of viscous mucus and making nonproductive coughs more productive and less frequent.

Indications and Usage

Temporary relief of symptoms of upper respiratory tract disorders such as sinusitis, vasomotor rhinitis, and hay fever; temporary relief of coughs associated with respiratory tract infections and related conditions such as sinusitis, pharyngitis, bronchitis, and asthma when tenacious mucus and/or mucus plugs and congestion complicate these conditions.

Contraindications

Hypersensitivity to any component of product; hypersensitivity or idiosyncrasy to sympathomimetic amines, which may manifest by insomnia, dizziness, weakness, tremor, or arrhythmias. Phenylephrine is contraindicated in patients with hypertension or ventricular tachycardia and should be employed only with extreme caution in elderly patients or in patients with hyperthyroidism, bradycardia, partial heart block, myocardial disease, or severe arteriosclerosis. Phenylephrine is contraindicated in patents on monoamine oxidase (MAO) inhibitor therapy and for 14 days after stopping MAO therapy (see Interactions section).

Dosage and Administration

Adults and Children (12 yr and older) Rescon-GG Liquid

PO 10 mL q 4 to 6 hr (up to 40 mL/day).

Entex Liquid

PO 5 to 10 mL q 4 to 6 hr (up to 40 mL/day).

Guaifed-PD Capsules

PO 1 to 2 q 12 hr.

Entex ER Capsules

PO 1 or 2 q 12 hr.

Guaifed Capsules

PO 1 q 12 hr.

SINUvent PE Tablets

PO 2 q 12 hr.

GFN 600/Phenylephrine 20 Tablets

PO 1 or 2 q 12 hr (up to 2/day).

Liquibid-PD Tablets

PO 1 or 2 q 12 hr (up to 4/day).

Liquibid-D Tablets

PO 1 q 12 hr.

Liquibid-D 1200 Tablets

PO 1 q 12 hr.

Children (6 to 12 yr)

PO ½ tablet q 12 hr (max, 1 tablets in 24 hr).

General Advice

• Give with food if GI upset occurs.
• Tablets may be broken in half for ease of administration. Do not crush or chew tablets or half-tablets.

Storage/Stability

Store tablets at controlled room temperature (59° to 86°F).

Drug Interactions

Beta-adrenergic blockers, MAO inhibitors

May potentiate the pressor effect of phenylephrine.

Digitalis glycosides, other vasopressor drugs during halothane anesthesia

The risk of cardiac arrhythmias may be increased.

Guanethidine, mecamylamine, methyldopa, reserpine, veratrum alkaloids

Hypotensive effects of these agents may be reduced.

Tricyclic antidepressants

Effects of phenylephrine may be decreased.

Laboratory Test Interactions

Guaifenesin may interfere with the interpretation of the test for urinary 5-hydroxyindoleacetic acid for the diagnosis of carcinoid syndrome; VMA test for catecholamines may be falsely elevated; guaifenesin may increase renal clearance for urate and thereby lower serum uric acid levels.

Adverse Reactions

Cardiovascular

Tachycardia; palpitations; arrhythmias; cardiovascular collapse with hypotension.

CNS

Headache; dizziness; fear; anxiety; nervousness; restlessness; tremor; weakness; insomnia; hallucinations; convulsions; CNS depression.

GI

Nausea.

Genitourinary

Dysuria.

Respiratory

Respiratory difficulty.

Miscellaneous

Pallor.

Precautions

Pregnancy

Category C .

Lactation

Small amounts of phenylephrine excreted in breast milk.

Children

Not recommended for use in children under 6 yr.

Elderly

Patients 60 yr and older are more likely to experience adverse sympathomimetic effects.

Special Risk Patients

Use with caution in patients with hypertension, heart disease, asthma, hyperthyroidism, increased intraocular pressure, diabetes mellitus, prostatic hypertrophy.

Drug abuse

Has abuse potential.

Overdosage

Symptoms

Cardiac arrhythmias, cerebral hemorrhage, pulmonary edema, palpitation, tremor, dizziness, vomiting, fear, labored breathing, headache, dryness of mouth, pallor, weakness, panic, anxiety, confusion, hallucinations, delirium.

Patient Information

• Explain name, dose, action, and potential side effects of drug.
• Advise patient how to properly take medication.
• Advise patient that tablets may be broken in half for ease of administration.
• Instruct patient to not chew or crush tablets or half-tablets and to swallow whole.
• Advise patient to take with food if GI upset occurs.
• Advise patient that if a dose is missed to take as soon as remembered unless it is nearing time for the next dose. Caution patient to not double the dose to catch up.
• Instruct patient to discontinue use and report any of the following symptoms to health care provider: nervousness, dizziness, sleeplessness; persistent or recurrent cough; cough associated with fever, rash, or persistent headache; bothersome side effects.
• Advise patient that if symptoms are not controlled, not to increase the dose of medication but to inform health care provider.
• Advise women to notify health care provider if pregnant, planning to become pregnant, or breastfeeding.
• Caution patient to not take any prescription or OTC medications, or dietary supplements unless advised by health care provider.
• Caution patient not to take MAO inhibitor while taking this medication.