Can You Take Adipex-P (Phentermine) With Cold Medicine?

Answer

Phentermine (Adipex-P) has several interactions with over-the-counter cough/cold medications that are important to be aware of.

Specifically, caution needs to be taken before combining phentermine with:

• Dextromethorphan (cough suppressant)
• Pseudoephedrine (nasal decongestant)
• Phenylephrine (nasal decongestant)

We discuss these in more detail below.

Cold Medications To Use Cautiously

Phentermine With Dextromethorphan

Both phentermine and dextromethorphan can increase levels of the neurotransmitter serotonin. This increases the risk of a rare but serious condition known as serotonin syndrome, which is characterized by several symptoms, including:

• Agitation
• Anxiety
• Hyperthermia
• Mental status changes
• Cognitive impairment
• Seizures
• Rigidity
• Sweating
• Nausea
• Vomiting

While the overall risk of serotonin is relatively low for most individuals, combining medications with serotonin effects increases the risk.

There is some controversy regarding how strong an effect dextromethorphan has on serotonin. Some studies show that when taken at recommended doses, it doesn't increase levels.

Other studies however have presented case reports in which serotonin syndrome occurred on usual doses. It is important to speak with your doctor before combining phentermine with dextromethorphan.

It is also important to be aware that dextromethorphan is a very common ingredient in over-the-counter cough/cold medications. For example, it is included in NyQuil, DayQuil, and Tylenol Cold & Flu. Be sure to read the labels of the over-the-counter products you plan on purchasing.

Phentermine With Pseudoephedrine Or Phenylephrine

Taking phentermine with pseudoephedrine or phenylephrine can increase blood pressure and heart rate.

Phentermine is a stimulant medication, chemically similar to amphetamines. Both pseudoephedrine and phenylephrine have mild stimulating properties. Taking phentermine with a nasal decongestant can have additive effects.

Phentermine should not be used with either drug unless specifically directed by your doctor.

What Cold Medications Are Safe?

While you should avoid any of the medications previously discussed with phentermine unless you speak with your doctor, the following are considered to have no drug interactions:

Antihistamines

Antihistamines are considered safe to take with phentermine. While not often classified as 'cold' medications, antihistamines can help many related symptoms, including:

• Runny nose
• Congestion
• Watery eyes
• Postnasal drip (which could cause a cough)
• Insomnia (with sedating antihistamines like Benadryl)

Over-the-counter antihistamines include:

• Benadryl (sedating)
• Zyrtec
• Allegra
• Claritin

Pain Relievers

Both NSAID pain relievers (e.g. Advil, Aleve) and Tylenol (acetaminophen) are considered safe with phentermine. They can provide symptomatic relief for a variety of cold symptoms, including fever and headaches.

Expectorants

Mucinex (guaifenesin) is considered safe to use with phentermine. Mucinex helps to relieve chest congestion and can be helpful for post-nasal drip.

Other

Most "natural" products for cough relief are safe to use, including ones with honey. In addition, cough drops with menthol or ones with anesthetics (e.g. benzocaine) are considered safe.

Final Words

I hope this answer provided some assistance and please reach back out again if anything comes up!