Phenytoin and Doxycycline drug interactions - a phase IV clinical study of FDA data

Summary:

Drug interactions are reported among people who take Phenytoin (phenytoin) and Doxycycline (doxycycline hyclate). Common drug interactions include conjunctival abrasion among females and activities of daily living impaired among males.

The phase IV clinical study analyzes what interactions people have when they take Phenytoin and Doxycycline. It is created by eHealthMe based on reports of 47 people who take the same drugs from the FDA, and is updated regularly.

What is Phenytoin?

Phenytoin has active ingredients of phenytoin. It is often used in epilepsy. eHealthMe is studying from 15,753 Phenytoin users. Check the latest studies of Phenytoin.

What is Doxycycline?

Doxycycline has active ingredients of doxycycline hyclate. It is often used in acne. eHealthMe is studying from 60,866 Doxycycline users. Check the latest studies of Doxycycline.

On Jul, 07, 2026

47 people who take Phenytoin and Doxycycline together, and have interactions are studied.

Phenytoin and Doxycycline drug interactions.

What are the common drug interactions of Phenytoin and Doxycycline, by gender? *:

female:

Conjunctival abrasion (injury to outer surface of eye)
Convulsion (muscles contract and relax rapidly and repeatedly, resulting in an uncontrolled shaking of the body)
Cough
Exostosis (formation of new bone on the surface of a bone)
Fall
Furuncle (infection of the hair follicle)
Gastrooesophageal reflux disease (stomach contents (food or liquid) leak backwards from the stomach into the oesophagus)
Melaena (the passage of black, tarry stools)
Neck pain
Neuropathy peripheral (surface nerve damage)

male:

Activities of daily living impaired
Alpha haemolytic streptococcal infection (infections with alpha-haemolytic strep bacteria are common; many strains live naturally in humans)
Osteomyelitis acute (rapid infection of bone)
Osteonecrosis of jaw (death of bone of jaw)
Pain
Pancreatic carcinoma (pancreatic cancer)
Prostatomegaly (enlargement of the prostate)
Renal cell carcinoma (a kidney cancer)
Renal mass (mass in kidney)
Small intestine carcinoma (cancer tumour of small intestine)

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

0-1:

n/a

2-9:

n/a

10-19:

n/a

20-29:

n/a

30-39:

Dysphagia (a condition in which swallowing is difficult or painful)
Oesophageal carcinoma (cancer tumour of oesophagus)

40-49:

Grand mal convulsion (a type of generalized seizure that affects the entire brain)
Activities of daily living impaired
Arthropathy
Dizziness
Loss of consciousness
Actinic keratosis (skin disease due to sun exposure)
Adenocarcinoma (malignant tumour formed from glandular structures in epithelial tissue)
Alpha haemolytic streptococcal infection (infections with alpha-haemolytic strep bacteria are common; many strains live naturally in humans)
Anaemia (lack of blood)
Angioedema (rapid swelling of the dermis)

50-59:

Conjunctival abrasion (injury to outer surface of eye)
Dizziness
Exostosis (formation of new bone on the surface of a bone)
Furuncle (infection of the hair follicle)
Gastrooesophageal reflux disease (stomach contents (food or liquid) leak backwards from the stomach into the oesophagus)
Melaena (the passage of black, tarry stools)
Neck pain
Neuropathy peripheral (surface nerve damage)
Otitis externa (external ear infection)
Otitis media (inflammation of the middle ear)

60+:

Cough
Dyspnoea (difficult or laboured respiration)
Bone lesion (bone with abnormalities. bone lesions can result from growth formations, infections, or injuries)
Diabetes mellitus (diabetes, caused by a deficiency of the pancreatic hormone insulin)
Disability
Enterobacter infection (infection caused by bacteria of the family enterobacteriaceae)
Exercise tolerance decreased
Hemiparesis (weakness on one side of the body)
Herpes virus infection
Injury

What are the existing conditions these people have? *

Convulsion (muscles contract and relax rapidly and repeatedly, resulting in an uncontrolled shaking of the body): 6 people, 12.77%
Restless Leg Syndrome (a powerful urge to move your legs): 3 people, 6.38%
Hyperlipidaemia (presence of excess lipids in the blood): 3 people, 6.38%

* Approximation only. Some reports may have incomplete information.

Do you take Phenytoin and Doxycycline?

- 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