Understanding What is acetaminophen diphenhydramine phenylephrine 44543?

October 8, 2025 •

4 min read

The pill imprinted with the code '44 543' is an over-the-counter medication identified as a severe allergy and sinus headache treatment. It is crucial to understand what is acetaminophen diphenhydramine phenylephrine 44543 to use it safely and effectively for managing common cold and allergy symptoms.

Quick Summary

The medication identified as '44 543' is an over-the-counter combination drug containing acetaminophen, diphenhydramine, and phenylephrine. It is used for the temporary relief of symptoms associated with severe allergies, sinus congestion, and headaches.

Key Points

Imprint code identification: The numbers '44 543' identify a specific over-the-counter (OTC) medication for severe allergy and sinus headache relief.
Multi-ingredient formula: This medication contains acetaminophen (pain reliever), diphenhydramine (antihistamine), and phenylephrine (nasal decongestant).
Intended for nighttime use: The presence of diphenhydramine, a sedating antihistamine, means this medication can cause significant drowsiness.
Phenylephrine effectiveness The FDA has questioned the efficacy of oral phenylephrine as a nasal decongestant, though it is still included in many products.
Risk of overdose: An overdose of the acetaminophen component can cause severe liver damage. It is critical not to exceed the recommended amount and to avoid other products containing acetaminophen.
Important drug interactions: This medication should not be taken with MAOIs or other sedating drugs due to potential for dangerous interactions.
Age restriction: This product is generally intended for adults. Younger individuals should not take this medication without a doctor's advice.

What is acetaminophen diphenhydramine phenylephrine 44543?

Acetaminophen diphenhydramine phenylephrine 44543 is the identification for a specific over-the-counter (OTC) combination medication. The imprint code '44 543' is used to identify caplets that are typically blue, oblong, and contain a combination of three active ingredients. This product is marketed for severe allergy and sinus headache relief, and understanding each component is key to its proper use.

The active ingredients and their functions

This multi-symptom medication combines three distinct pharmacological agents to combat a range of cold and allergy symptoms. Each ingredient targets a different aspect of the illness:

Acetaminophen: A non-aspirin pain reliever and fever reducer. It works by inhibiting chemical messengers in the brain that signal pain and fever, providing relief from headaches, body aches, and elevated temperatures.
Diphenhydramine HCl: A first-generation antihistamine. It blocks histamine, a substance the body releases during an allergic reaction. This action helps to alleviate classic allergy symptoms such as sneezing, runny nose, and itchy or watery eyes. Because it crosses the blood-brain barrier, it can cause significant drowsiness, which is why this formulation is typically intended for nighttime use.
Phenylephrine HCl: A nasal decongestant. It works by narrowing the blood vessels in the nasal passages, which reduces swelling and helps to relieve nasal and sinus congestion and pressure. It is important to note that the FDA has proposed removing oral phenylephrine from OTC monograph status, citing a lack of proven effectiveness as an oral nasal decongestant. The other ingredients in the combination product remain effective.

Therapeutic uses and symptom relief

This combination medication is used for the temporary relief of symptoms associated with hay fever, upper respiratory allergies, and the common cold.

Symptoms that may be relieved include:

Sinus headache
Minor aches and pains
Fever
Nasal and sinus congestion
Sneezing
Runny nose
Itchy, watery eyes
Itching of the nose or throat

Administration and safety precautions

When using this medication, it is important to follow the specific directions on the product label and from a healthcare provider. Different manufacturers and formulations may have slight variations. It is crucial to adhere to recommended guidelines to ensure safe and effective use.

Key Safety Warnings

Acetaminophen Overdose: Taking more than the recommended amount of acetaminophen can cause severe, potentially fatal, liver damage. Avoid taking other products containing acetaminophen while using this medication.
Drowsiness: The diphenhydramine component can cause marked drowsiness. Avoid driving or operating heavy machinery after taking this medication. The sedative effect is increased by alcohol, sedatives, and tranquilizers.
Allergic Reactions: In rare cases, acetaminophen can cause severe skin reactions like rashes, blistering, and skin reddening. Stop use and seek medical help if these symptoms occur.
Drug Interactions: Do not use this medication with a monoamine oxidase inhibitor (MAOI) or within 2 weeks of stopping an MAOI, as a dangerous drug interaction could occur. Consult a doctor or pharmacist before use if you are taking blood thinners like warfarin.
Pre-existing Conditions: Individuals with certain health conditions should consult a doctor before use, including those with liver disease, high blood pressure, heart disease, diabetes, glaucoma, or a thyroid disorder.

Comparison with other cold and allergy medications


Feature	Acetaminophen/Diphenhydramine/Phenylephrine (e.g., 44543)	Single-ingredient Acetaminophen	Single-ingredient Diphenhydramine	Single-ingredient Pseudoephedrine
Primary Use	Multi-symptom relief for cold, flu, and severe allergies, including sinus headache.	Pain relief and fever reduction.	Allergy symptom relief, insomnia.	Nasal and sinus congestion relief.
Primary Active Ingredients	Acetaminophen, Diphenhydramine, Phenylephrine	Acetaminophen	Diphenhydramine	Pseudoephedrine
Drowsiness	Yes, significant (Nighttime formula).	No.	Yes, significant.	No, can cause restlessness.
Key Advantage	Addresses multiple symptoms with one product.	Focused relief for pain and fever, less side effects.	Effective allergy relief and sleep aid.	Considered a more effective oral decongestant than phenylephrine.
Key Disadvantage	Combining ingredients may lead to unnecessary drug exposure; potential side effects.	Does not treat congestion or allergy symptoms.	Does not treat pain, fever, or congestion.	Less convenient to purchase (behind-the-counter) due to pseudoephedrine restrictions.
Oral Decongestant Efficacy	Low, based on FDA review of oral phenylephrine.	N/A	N/A	High efficacy.

Conclusion

The product known as acetaminophen diphenhydramine phenylephrine 44543 is a combination over-the-counter medicine designed to provide comprehensive relief for severe allergy and cold symptoms accompanied by sinus headaches. By combining a pain reliever, an antihistamine, and a decongestant, it targets multiple ailments simultaneously. However, consumers must be aware of the potential for significant drowsiness and the FDA's findings regarding the questionable efficacy of oral phenylephrine as a decongestant. As with any medication, it is vital to follow instructions carefully and consult a healthcare professional, especially when dealing with pre-existing conditions or taking other medications. For individuals seeking strong multi-symptom relief for nighttime use, this product can be effective, provided all safety warnings are heeded.

Visit the DailyMed listing for a full rundown of this and similar products.

Frequently Asked Questions

The pill with the imprint '44 543' is an over-the-counter combination medication for severe allergy and sinus headache relief, containing acetaminophen, diphenhydramine, and phenylephrine.

This medication temporarily relieves symptoms of hay fever or upper respiratory allergies, including headache, sinus congestion, nasal congestion, sneezing, runny nose, and itchy, watery eyes.

No, because it contains diphenhydramine, a sedating antihistamine, it can cause marked drowsiness. It is typically intended for nighttime use, and you should avoid driving or operating machinery after taking it.

It is important to follow the directions on the product label or from your healthcare provider regarding how often to take this medication. Do not exceed the recommended frequency or amount.

Yes, taking more than the recommended amount can lead to severe liver damage. You should not use any other products containing acetaminophen while taking this medication.

Yes, the FDA has proposed removing oral phenylephrine from OTC products, stating it is not effective as a nasal decongestant. The other active ingredients, however, remain effective.

You should not use this product if you are taking a monoamine oxidase inhibitor (MAOI), any other medication containing acetaminophen or diphenhydramine, or if you have certain pre-existing health conditions such as liver disease, glaucoma, heart disease, or high blood pressure.