Levothroid and Phentermine drug interactions - a phase IV clinical study of FDA data

Summary:

Drug interactions are reported among people who take Levothroid (levothyroxine sodium) and Phentermine (phentermine hydrochloride). Common drug interactions include cardiovascular disorder among females and insomnia among males.

The phase IV clinical study analyzes what interactions people have when they take Levothroid and Phentermine. It is created by eHealthMe based on reports of 12 people who take the same drugs from the FDA, and is updated regularly.

What is Levothroid?

Levothroid has active ingredients of levothyroxine sodium. It is often used in hypothyroidism. eHealthMe is studying from 8,974 Levothroid users. Check the latest studies of Levothroid.

What is Phentermine?

Phentermine has active ingredients of phentermine hydrochloride. It is often used in weight loss. eHealthMe is studying from 19,870 Phentermine users. Check the latest studies of Phentermine.

On Jul, 14, 2026

12 people who take Levothroid and Phentermine together, and have interactions are studied.

Levothroid and Phentermine drug interactions.

What are the common drug interactions of Levothroid and Phentermine, by gender? *:

female:

Cardiovascular disorder (heart diseases)
Bronchiectasis (abnormal widening of the bronchi or their branches, causing a risk of infection)
Cardiac murmur (an heart sound in valve abnormality)
Chest pain
Chronic kidney disease
Convulsions (muscles contract and relax rapidly and repeatedly, resulting in an uncontrolled of muscles contract and relax rapidly and repeatedly)
Decreased activity
Dermatitis (inflammation of the skin resulting from direct irritation by an external agent or an allergic reaction to it)
Difficulty in walking
Dizziness

male:

Insomnia (sleeplessness)

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

0-1:

n/a

2-9:

n/a

10-19:

n/a

20-29:

Cardiovascular disorder (heart diseases)
Dry mouth
Pulmonary hypertension (increase in blood pressure in the lung artery)

30-39:

Cardiovascular disorder (heart diseases)
Drug withdrawal syndrome (interfere with normal social, occupational, or other functioning. are not due to another medical condition, drug use, or discontinuation)
Headache (pain in head)
Nervousness

40-49:

Asthma
Cardiovascular disorder (heart diseases)
Hypokalaemia (low potassium)
Syncope (loss of consciousness with an inability to maintain postural tone)
Aortic valve incompetence
Cardiac murmur (an heart sound in valve abnormality)
Drug ineffective
Tricuspid valve incompetence (inefficient heart valve)
Valvular heart disease (diseases of the heart valves)

50-59:

Chronic kidney disease

60+:

Dyspnoea (difficult or laboured respiration)
Basedow's disease (autoimmune disease where the thyroid is overactive, producing an excessive amount of thyroid hormones)
Dizziness
Drug hypersensitivity
Dysphonia (speech disorder attributable to a disorder of phonation)
Dysstasia (difficulty in standing)
Eye swelling
Fatigue (feeling of tiredness)
Gait disturbance
Limb discomfort (discomfort in leg)

What are the existing conditions these people have? *

Pain: 2 people, 16.67%
Multiple Sclerosis (a nervous system disease that affects your brain and spinal cord. it damages the myelin sheath): 2 people, 16.67%
Growth Hormone Deficiency: 2 people, 16.67%
Weakness: 1 person, 8.33%
Pain In Extremity: 1 person, 8.33%
Mental Disorder (a psychological term for a mental or behavioural pattern or anomaly that causes distress or disability): 1 person, 8.33%
Inflammation: 1 person, 8.33%
Gastroesophageal Reflux Disease (a condition in which stomach contents leak backward from the stomach into the oesophagus): 1 person, 8.33%
Appetite - Decreased (decreased appetite occurs when you have a reduced desire to eat): 1 person, 8.33%

* Approximation only. Some reports may have incomplete information.

Do you take Levothroid and Phentermine?

- 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