Phenylephrine-Guaifenesin (guaifenesin/phenylephrine HCl)
Last reviewed · Source: First Databank (FDB) drug data
Overview
Phenylephrine hydrochloride is an alpha1-adrenergic receptor agonist.
Guaifenesin is an expectorant.
The phenylephrine activation of alpha1-adrenergic receptors on vascular smooth muscle cells results in vasoconstriction. Following IV administration of phenylephrine hydrochloride, systolic and diastolic blood pressure, mean arterial blood pressure, and total peripheral vascular resistance are increased. Vasoconstriction occurs in most vascular beds, including renal, pulmonary, and splanchnic arteries, but minimal to no effect is observed on cerebral blood vessels.
Hepatic vascular beds are also affected. In some patients, phenylephrine can substantially reduce cardiac output, presumably due to increased afterload; however, the exact effects of the drug on global cardiac output depend on the dose and contributory effects of the arterial and venous vasculature. Although phenylephrine reduces venous compliance and can potentially increase venous return, accompanying increases in arterial and venous resistance can negate this potential benefit.
With increased blood pressure following IV administration, there is increased vagal activity, resulting in reflex bradycardia. Phenylephrine constricts both arterial and venous blood vessels, although its effects on arterial vessels are more pronounced. At clinically relevant dosages, phenylephrine increases myocardial work and oxygen requirements.
Following an IV bolus of phenylephrine hydrochloride, blood pressure increase is rapid, typically occurring within minutes. Blood pressure effects from a phenylephrine bolus may persist for up to 20 minutes. Phenylephrine is widely distributed into organs and peripheral tissues.
It is not known if phenylephrine or its metabolite are distributed into human or animal milk following parenteral administration.
Phenylephrine is extensively metabolized in the liver. Phenylephrine primarily undergoes metabolism by sulfotransferase and monoamine oxidase (MAO) to pharmacologically inactive metabolites. The 2 major metabolites are m-hydroxymandelic acid and sulfate conjugates.
Following IV administration of phenylephrine, approximately 86% of the dose is excreted in urine within 48 hours, principally as metabolites; approximately 16% of the dose is excreted in urine as unchanged drug. The terminal elimination half-life of phenylephrine averages 2.5 hours following IV administration. The observed effective half-life is approximately 5 minutes following IV infusion of the drug.
Patients with hepatic cirrhosis may have a reduced response to phenylephrine, potentially requiring higher dosages of the drug. Patients with end-stage renal disease may have an increased response to phenylephrine, potentially requiring lower dosages of the drug.
USES: This combination medication is used to temporarily treat cough and runny/stuffy nose (nasal congestion) caused by infections (such as the common cold), allergies (such as hay fever), and other breathing illnesses. This product is usually not used for ongoing cough from smoking or long-term breathing problems (such as chronic bronchitis, emphysema) unless directed by your doctor. Guaifenesin is an expectorant.
It works by thinning and loosening mucus in the airways, clearing congestion, and making breathing easier. Phenylephrine is a decongestant (sympathomimetic). It reduces nasal congestion by narrowing the blood vessels in the nose.
If you are self-treating with this medication, it is important to read the package instructions carefully before you start using this product to be sure it is right for you. (See also Precautions section.) Cough-and-cold products have not been shown to be safe or effective in children younger than 6 years. Do not use this product to treat cold symptoms in children younger than 6 years unless specifically directed by the doctor. Some products (such as long-acting tablets/capsules) are not recommended for use in children younger than 12 years.
Ask your doctor or pharmacist for more details about using your product safely. These products do not cure or shorten the length of the common cold and may cause serious side effects. To decrease the risk for serious side effects, carefully follow all dosage directions.
Do not give other cough-and-cold medication that might contain the same or similar ingredients (see also Drug Interactions section). Ask the doctor or pharmacist about other ways to relieve cough and cold symptoms (such as drinking enough fluids, using a humidifier or saline nose drops/spray).
Generic name: guaifenesin/phenylephrine HCl
Pronunciation: (gweye-FEN-eh-sin/fen-ill-EFF-rin)
Reference product & biosimilars
No reference, biosimilar or interchangeable associated with this drug.
Today’s intelligence on Phenylephrine-Guaifenesin
Indications
The following indications are listed for Phenylephrine-Guaifenesin:
- Cold Symptoms
- Cough
- Nasal Congestion
- Rhinitis
- Rhinorrhea
Also known as: Nasal Stuffiness.
Dosing
No dosing information is available for this tab.
Phenylephrine hydrochloride is administered by IV bolus or continuous IV infusion for the treatment of clinically important hypotension. The drug is available as a 10 mg/mL phenylephrine hydrochloride injection concentrate that must be diluted prior to administration and as a ready-to-use phenylephrine hydrochloride 100 mcg/mL (Immphentiv(R), Biorphen(R)) injection. Ready-to-use phenylephrine hydrochloride 100 mcg/mL (Immphentiv(R), Biorphen(R)) injection should not be further diluted before IV bolus administration.
For treatment of hypotension during anesthesia, the manufacturers recommend administration of phenylephrine hydrochloride as an IV bolus or continuous infusion; when used in the treatment of septic shock, the drug should be administered as a continuous IV infusion with no initial bolus dose. Phenylephrine hydrochloride injection should be stored at 20-25degreesC, but may be exposed to temperatures ranging from 15-30degreesC; single-dose and pharmacy bulk vials should be kept in their original carton until time of use and protected from light.
Commercially available phenylephrine hydrochloride injection concentrate must be diluted with a compatible IV solution prior to administration. Diluted solutions may be stored at room temperature for up to 4 hours or under refrigeration for up to 24 hours; any unused portions should be discarded.
Commercially available phenylephrine hydrochloride bulk vials are intended for use in a pharmacy admixture program for preparation of single doses to be dispensed to multiple patients. Each vial should be penetrated only one time with a suitable sterile transfer device or dispensing set. Dispensing from a pharmacy bulk vial should be completed within 4 hours after the vial is penetrated.
Prior to administration, phenylephrine hydrochloride solutions should be inspected visually for particulate matter and discoloration; the drug should be discarded if the solution is colored, cloudy, or contains any particulate matter.
Care should be taken to avoid extravasation and the infusion site should be checked for free flow.
Guaifenesin is administered orally.
Mucinex(R) 600-mg extended-release tablets should not be broken, crushed, or chewed and should not be used in children younger than 12 years of age; the tablets should be kept out of reach of young children to avoid accidental swallowing and choking.
No dosing information is available for this tab.
No dosing information is available for this tab.
Drug interactions
There is no enhanced messaging for this drug.
There are no contraindication interactions for this drug.
There are no severe interactions for this drug.
There are no moderate interactions for this drug.
Contraindications
*Known hypersensitivity to phenylephrine or to any ingredient in the respective formulation.
There are no contraindication contraindications for this drug.
There are no severe contraindications for this drug.
There are no moderate contraindications for this drug.
Adverse reactions
The most commonly reported adverse effects in patients receiving IV phenylephrine hydrochloride were nausea, vomiting, and headache.
There are no severe adverse reactions for this drug.
There are no less severe adverse reactions for this drug.
Precautions
No enhanced messaging available.
The manufacturers state that safety and efficacy of parenteral preparations of phenylephrine hydrochloride have not been established in pediatric patients.
Data from randomized trials and meta-analyses with phenylephrine injection in pregnant women undergoing Cesarean section have not established a drug-associated risk of major birth defects or miscarriage. Additionally, the data did not identify adverse effects on maternal outcomes or infant Apgar scores. At recommended doses, phenylephrine does not appear to significantly affect fetal heart rate or fetal heart rate variability. Data are not available on phenylephrine use during the first or second trimester.
Untreated hypotension in pregnant women undergoing Cesarean delivery with neuraxial anesthesia has been associated with increased maternal nausea and vomiting. A sustained decrease in uterine blood flow caused by maternal hypotension has also been associated with fetal bradycardia and acidosis.
No data are available on the safety of phenylephrine injection during the period of organogenesis; therefore, conclusions cannot be drawn regarding the risk of birth defects from drug exposure. In addition, no data are available on the risk of miscarriage following fetal exposure to phenylephrine injection.
In animal studies, fetal malformations were observed following phenylephrine infusion over 1 hour during the period of organogenesis at a dosage of 1.2 times the human daily dosage. Decreased pup weight was also observed in offspring of pregnant rats who received 2.9 times the human daily dose of phenylephrine.
If a vasopressor is used in conjunction with oxytocic drugs, the vasopressor effect is potentiated and may result in serious adverse effects.
There are no data on whether phenylephrine or its metabolite is distributed into human or animal milk following parenteral administration. The effects on the breast-fed infant and milk production are not known.
The developmental and health benefits of breast-feeding should be weighed along with the mother's clinical need for the drug and any potential adverse effects on the breast-fed infant from phenylephrine or from the underlying maternal condition.
If phenylephrine is used in geriatric patients, dosage should be selected carefully, usually starting at the low end of the dosage range, since renal, hepatic, and cardiovascular dysfunction and concomitant disease or other drug therapy are more common in this age group.
Clinical studies of phenylephrine hydrochloride did not include sufficient numbers of patients >=65 years of age to determine whether geriatric patients respond differently than younger patients. Clinical experience to date has not identified any differences in response between geriatric and younger patients.
If phenylephrine is used in geriatric patients, dosage should be selected carefully, usually starting at the low end of the dosage range, since renal, hepatic, and cardiovascular dysfunction and concomitant disease or other drug therapy are more common in this age group.
ICD codes
No ICD codes are available for this drug.
Formulary status
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Last reviewed · Source: First Databank (FDB) drug data
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