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Despec (Generic Phenylephrine)

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Why is this medication prescribed?

Despec is commonly prescribed to relieve symptoms associated with respiratory conditions such as the common cold, flu, allergies, and sinusitis. Its active ingredients, guaifenesin and phenylephrine, work synergistically to alleviate congestion, promote drainage of mucus from the respiratory tract, and reduce nasal congestion and sinus pressure.

Guaifenesin is an expectorant, which means it helps loosen and thin mucus in the airways, making it easier to cough up and clear from the lungs. Phenylephrine is a decongestant that works by narrowing blood vessels in the nasal passages, reducing swelling and congestion.

How should this medicine be used?

Despec typically comes in the form of tablets or syrup. The dosage and frequency of use may vary depending on the individual’s age, medical condition, and response to treatment. It’s essential to follow the instructions provided by your healthcare provider or on the medication label carefully.

Here are some general guidelines for using Despec:

  • Take Despec exactly as prescribed by your doctor or as directed on the label.
  • Swallow tablets whole with a full glass of water. Do not crush or chew them unless instructed otherwise.
  • Shake the syrup well before each use and measure the dose using a proper measuring device, such as a medicine cup or spoon.
  • Do not exceed the recommended dosage or use Despec for longer than advised by your doctor. Doing so may increase the risk of side effects.
  • If you miss a dose, take it as soon as you remember. However, if it’s almost time for your next dose, skip the missed dose and continue with your regular dosing schedule.
  • Store Despec at room temperature away from moisture, heat, and light. Keep it out of reach of children and pets.
  • If your symptoms persist or worsen despite taking Despec, or if you experience severe or persistent side effects, contact your doctor promptly.

It’s crucial to use Despec only for the condition it’s prescribed for and to avoid combining it with other over-the-counter or prescription medications without consulting your doctor, as it may lead to drug interactions or excessive dosage of certain active ingredients.

Other uses for this medicine

Some potential off-label uses of Despec may include:

  • Relief of congestion and cough associated with bronchitis or other respiratory infections.
  • Management of symptoms related to allergic rhinitis or hay fever.
  • Supportive treatment for bronchial asthma exacerbations, especially in cases with associated congestion and mucus production.
  • Adjunctive therapy for acute otitis media (middle ear infection) to alleviate nasal congestion and promote drainage.

What special precautions should I follow?

Regarding special precautions for Despec use, here are some important points to keep in mind:

  • Medical History: Inform your doctor about any pre-existing medical conditions you have, especially hypertension (high blood pressure), heart disease, diabetes, thyroid disorders, glaucoma, prostate enlargement, urinary retention, or liver or kidney disease. These conditions may influence the suitability of Despec or require dosage adjustments.
  • Pregnancy and Breastfeeding: If you are pregnant or breastfeeding, discuss the risks and benefits of using Despec with your doctor before taking it. Some ingredients in Despec may pass into breast milk or affect the developing fetus, so caution is advised.
  • Allergies: Inform your doctor about any allergies you have, particularly to guaifenesin, phenylephrine, or any other ingredients in Despec. Allergic reactions to medications can range from mild to severe and may require immediate medical attention.
  • Interactions: Despec may interact with certain medications, including monoamine oxidase inhibitors (MAOIs), tricyclic antidepressants, beta-blockers, diuretics, and other sympathomimetic agents. Inform your doctor about all prescription, over-the-counter, and herbal products you are taking to avoid potential interactions.
  • Driving and Operating Machinery: Despec may cause dizziness, drowsiness, or blurred vision in some individuals. Avoid driving, operating machinery, or performing tasks that require alertness until you know how Despec affects you.
  • Alcohol: Avoid consuming alcohol while taking Despec, as it may intensify certain side effects such as dizziness or drowsiness.

Always follow your doctor’s recommendations and the instructions provided with Despec to ensure safe and effective use. If you have any concerns or experience adverse reactions while taking Despec, contact your healthcare provider promptly.

What special dietary instructions should I follow?

Special dietary instructions for Despec typically involve staying hydrated by drinking plenty of fluids, which can help thin mucus and facilitate its clearance from the respiratory tract. However, there are no specific dietary restrictions associated with Despec unless otherwise advised by your doctor.

What should I do if I forget a dose?

If you forget a dose of Despec, take it as soon as you remember. However, if it’s almost time for your next scheduled dose, skip the missed dose and continue with your regular dosing schedule. Do not double the dose to catch up. If you are unsure about what to do, consult your healthcare provider or pharmacist for guidance.

What side effects can this medication cause?

Despec, like any medication, may cause side effects in some individuals. Not everyone will experience these side effects, and their severity can vary. Common side effects of Despec may include:

  • Dizziness
  • Drowsiness
  • Nervousness or restlessness
  • Headache
  • Nausea
  • Upset stomach
  • Dry mouth
  • Trouble sleeping (insomnia)
  • Increased heart rate (tachycardia)
  • Elevated blood pressure (hypertension)
  • Difficulty urinating or urinary retention
  • Blurred vision
  • Allergic reactions, including rash, itching, swelling of the face, lips, or tongue, or difficulty breathing

These are not all the possible side effects of Despec. If you experience any other unusual symptoms while taking Despec, or if any of these side effects persist or worsen, contact your healthcare provider promptly.

It’s essential to seek medical attention immediately if you experience symptoms of a serious allergic reaction to Despec, such as rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, or trouble breathing.

Additionally, Despec contains phenylephrine, which can rarely cause serious side effects such as severe dizziness or headache, fast/irregular heartbeat, mental/mood changes (such as confusion, hallucinations), seizure, or difficulty urinating. If you experience any of these symptoms, seek immediate medical attention.

To minimize the risk of side effects, it’s important to take Despec exactly as prescribed by your doctor and to inform them of any pre-existing medical conditions you have and any other medications or supplements you are taking, including over-the-counter drugs and herbal remedies.

What should I know about storage and disposal of this medication?

When it comes to storage and disposal of Despec:


  • Keep Despec tightly closed in its original container at room temperature away from moisture, heat, and light.
  • Store it out of reach of children and pets to prevent accidental ingestion.


  • Dispose of unused or expired Despec properly according to local guidelines or as instructed by your pharmacist.
  • Do not flush Despec down the toilet or pour it down the drain unless instructed to do so. Instead, discard it in a sealed container, such as a plastic bag, and dispose of it in the household trash.

In case of emergency/overdose

  • If you suspect an overdose or experience severe symptoms such as difficulty breathing, chest pain, hallucinations, seizures, or loss of consciousness, seek immediate medical attention or contact a poison control center (in the United States, you can reach Poison Help at 1-800-222-1222).
  • Be prepared to provide information about the amount of Despec ingested, the time of ingestion, and any symptoms experienced.

What other information should I know?

  • Despec is for oral use only. Do not crush, chew, or break the tablets unless directed by your doctor.
  • Avoid consuming alcoholic beverages while taking Despec, as it may increase the risk of certain side effects.
  • Despec may cause dizziness, drowsiness, or blurred vision. Use caution when driving, operating machinery, or performing tasks that require alertness until you know how Despec affects you.
  • Keep all appointments with your doctor and laboratory while taking Despec to monitor your response to treatment and any potential side effects.
  • Do not share Despec with others, even if they have similar symptoms, as it may not be suitable for their condition or may interact with other medications they are taking.

If you have any further questions or concerns about Despec, its storage, use, or disposal, consult your healthcare provider or pharmacist for guidance.

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