Mucinex d and Synthroid drug interactions - a phase IV clinical study of FDA data

Summary:

Drug interactions are reported among people who take Mucinex d (guaifenesin; pseudoephedrine hydrochloride) and Synthroid (levothyroxine sodium). Common drug interactions include dry mouth among females and anhedonia among males.

The phase IV clinical study analyzes what interactions people have when they take Mucinex d and Synthroid. It is created by eHealthMe based on reports of 94 people who take the same drugs from the FDA, and is updated regularly.

What is Mucinex d?

Mucinex d has active ingredients of guaifenesin; pseudoephedrine hydrochloride. It is often used in sinus congestion. eHealthMe is studying from 1,926 Mucinex d users. Check the latest studies of Mucinex d.

What is Synthroid?

Synthroid has active ingredients of levothyroxine sodium. It is often used in hypothyroidism. eHealthMe is studying from 249,198 Synthroid users. Check the latest studies of Synthroid.

On Jul, 18, 2026

94 people who take Mucinex d and Synthroid together, and have interactions are studied.

Mucinex d and Synthroid drug interactions.

What are the common drug interactions of Mucinex D and Synthroid, by gender? *:

female:

Dry mouth
Dysgeusia (disorder of the sense of taste)
Eye pain
Fall
Fungal infection
Hypogeusia (reduced ability to taste things (to taste sweet, sour, bitter, or salty substances))
Hypoxia (low oxygen in tissues)
Hysterectomy
Lactose intolerance (inability to digest lactose)
Fatigue (feeling of tiredness)

male:

Anhedonia (inability to experience pleasure from activities usually found enjoyable)
Anxiety
Atrial fibrillation (fibrillation of the muscles of the atria of the heart)
Atrial flutter (an abnormal heart rhythm that occurs in the atria of the heart)
Bladder disorder
Cardiac failure
Drug ineffective
Insomnia (sleeplessness)
Joint swelling
Muscle spasms (muscle contraction)

What are the common drug interactions of Mucinex D and Synthroid, by age (0-1 to 60+)? *:

0-1:

n/a

2-9:

n/a

10-19:

n/a

20-29:

Anxiety
Fatigue (feeling of tiredness)
Hypertonic bladder (bladder-storage function that causes a sudden urge to urinate)
Intervertebral disc protrusion (spinal disc protrusion)
Rheumatoid arthritis (a chronic progressive disease causing inflammation in the joints)
Sciatica (a set of symptoms including pain caused by general compression or irritation of one of five spinal nerve roots of each sciatic nerve)
Synovial cyst (cyst of joint filled with synovial fluid)

30-39:

Abdominal pain
Breast cancer
Ear infection
Fluid overload (too much fluid in the blood)
Migraine (headache)
Movement disorder (neurological syndromes where they may be excess of movement or a paucity of movement that is not connected to weakness)
Myalgia (muscle pain)
Oedema peripheral (superficial swelling)
Pain in extremity
Pyrexia (fever)

40-49:

Injection site erythema (redness at injection site)
Arthralgia (joint pain)
Cough
Erythema (redness of the skin)
Injection site pain
Injection site pruritus (severe itching at injection site)
Injection site reaction
Injection site swelling
Injection site warmth
Peripheral swelling

50-59:

Injection site erythema (redness at injection site)
Injection site vesicles (fluid- or air-filled cavity or sac at injection site)
Malignant neoplasm progression (cancer tumour came back)
Mucosal inflammation (infection of mucous membrane)
Oropharyngeal pain
Spondylitis (an inflammation of the vertebra with spinal cord involvement)
Tumour marker increased
Anhedonia (inability to experience pleasure from activities usually found enjoyable)
Anxiety
Depression

60+:

Epistaxis (bleed from the nose)
Cardiac valve disease (heart valve disease)
Pyrexia (fever)
Colitis (inflammation of colon)
Dyspnoea (difficult or laboured respiration)
Fatigue (feeling of tiredness)
Nausea (feeling of having an urge to vomit)
Respiratory tract infection
Seasonal allergy (allergic condition due to certain season)
Decreased appetite

What are the existing conditions these people have? *

Immunodeficiency Common Variable: 32 people, 34.04%
Narcolepsy (brain's inability to regulate sleep-wake cycles normally): 14 people, 14.89%
Cataplexy (loss of muscle tone accompanied by full conscious awareness): 8 people, 8.51%
Multiple Myeloma (cancer of the plasma cells): 6 people, 6.38%
Pain: 5 people, 5.32%
Multiple Sclerosis (a nervous system disease that affects your brain and spinal cord. it damages the myelin sheath): 5 people, 5.32%
Drowsiness: 5 people, 5.32%

* Approximation only. Some reports may have incomplete information.

Do you take Mucinex d and Synthroid?

- Personalize this study to your gender, age, symptoms and drugs
- Predict drug outcomes for up to one year with AI
- Get an AI agent to monitor your drugs continuously