Thiola Side Effects Center

Last updated on RxList: 11/16/2022
Thiola Side Effects Center

Medical Editor: John P. Cunha, DO, FACOEP

What Is Thiola?

Thiola (tiopronin) is an active reducing agent indicated for the prevention of cystine (kidney) stone formation in patients with severe homozygous cystinuria with urinary cystine greater than 500 mg/day, who are resistant to treatment with conservative measures of high fluid intake, alkali and diet modification, or who have adverse reactions to d-penicillamine.

What Are Side Effects of Thiola?

What are the possible side effects of Thiola?

Thiola may cause serious side effects including:

  • hives,
  • difficulty breathing,
  • swelling of your face, lips, tongue, or throat,
  • rash,
  • fever,
  • swollen glands,
  • joint pain,
  • puffy eyes,
  • swelling in your ankles or feet,
  • weight gain, and
  • foamy urine

Get medical help right away, if you have any of the symptoms listed above.

Common side effects of Thiola include:

Seek medical care or call 911 at once if you have the following serious side effects:

  • Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
  • Serious heart symptoms such as fast, irregular, or pounding heartbeats; fluttering in your chest; shortness of breath; and sudden dizziness, lightheadedness, or passing out;
  • Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors.

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

Dosage for Thiola

The starting dose of Thiola is 800 mg/day in adult patients with cystine stones.

What Drugs, Substances, or Supplements Interact with Thiola?

Thiola may interact with other drugs. Tell your doctor all medications and supplements you use.

Thiola During Pregnancy and Breastfeeding

Thiola is not recommended for use during pregnancy; it may harm a fetus. Thiola passes into breast milk. Breastfeeding while taking Thiola is not recommended.

Additional Information

Our Thiola (tiopronin) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


Kidney Stones: Symptoms, Causes, and Treatment See Slideshow
Thiola Professional Information


The following adverse reactions are discussed in greater detail in other sections of the labeling:

  • Proteinuria [see WARNINGS AND PRECAUTIONS]
  • Hypersensitivity [see WARNINGS AND PRECAUTIONS]

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, the adverse reaction rates observed in the clinical trials of the drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

Adverse reactions occurring at an incidence of ≥5% in an uncontrolled trial in 66 patients with cystinuria age 9 to 68 years are shown in the table below. Patients in group 1 had previously been treated with d-penicillamine; those in group 2 had not. Of those patients who had stopped taking d-penicillamine due to toxicity (34 out of 49 patients in group 1), 22 were able to continue treatment with THIOLA. In those without prior history of d-penicillamine treatment, 6% developed reactions of sufficient severity to require THIOLA withdrawal.

Table 1 presents adverse reactions ≥5% in either treatment group occurring in this trial.

Table 1: Adverse Reactions Occurring in One or More Patients

System Organ ClassAdverse ReactionGroup 1 Previously treated with d-penicillamine
(N = 49)
Group 2 Naive to d-penicillamine
(N = 17)
Blood and Lymphatic System Disordersanemia1 (2%)1 (6%)
Gastrointestinal Disordersnausea12 (25%)2 (12%)
emesis5 (10%)-
diarrhea/soft9 (18%)1 (6%)
stools abdominal pain_1 (6%)
oral ulcers6 (12%)3 (18%)
General Disorders and Administration Site Conditionsfever4 (8%)-
weakness2 (4%)2 (12%)
fatigue7 (14%)-
peripheral3 (6%)1 (6%)
(edema) chest pain_1 (6%)
Metabolism and Nutrition Disordersanorexia4 (8%)-
Musculoskeletal and Connective Tissue Disordersarthralgia-2 (12%)
Renal and Urinary Disordersproteinuria5 (10%)1 (6%)
impotence-1 (6%)
Respiratory, Thoracic and Mediastinal Disorderscough-1 (6%)
Skin and Subcutaneous Tissue Disordersrash7 (14%)2 (12%)
ecchymosis3 (6%)-
pruritus2 (4%)1 (6%)
urticaria4 (8%)-
skin wrinkling3 (6%)1 (6%)

Taste Disturbance

A reduction in taste perception may develop. It is believed to be the result of chelation of trace metals by tiopronin. Hypogeusia is often self-limited.

Postmarketing Experience

Adverse reactions have been reported from the literature, as well as during post-approval use of THIOLA. Because the post-approval reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to THIOLA exposure.

Adverse reactions reported during the postmarketing use of THIOLA are listed by body system in Table 2.

Table 2: Adverse Reactions Reported for THIOLA Pharmacovigilance by System Organ Class and Preferred Term

System Organ ClassPreferred Term
Cardiac Disorderscongestive heart failure
Ear and Labyrinth Disordervertigo
Gastrointestinal Disordersabdominal discomfort; abdominal distension; abdominal pain; chapped lips; diarrhea; dry mouth; dyspepsia; eructation; flatulence; gastrointestinal disorder; gastroesophageal reflux disease; nausea; vomiting; jaundice; liver transaminitis
General Disorders and Administrationasthenia; chest pain; fatigue; malaise; pain; peripheral swelling; pyrexia; swelling
Site Conditions Investigationsglomerular filtration rate decreased; weight increased
Metabolism and Nutrition Disordersdecreased appetite; dehydration; hypophagia
Musculoskeletal and Connective Tissue Disordersarthralgia; back pain; flank pain; joint swelling; limb discomfort; musculoskeletal discomfort; myalgia; neck pain; pain in extremity
Nervous System Disordersageusia; burning sensation; dizziness; dysgeusia; headache; hypoesthesia
Renal and Urinary Disordersnephrotic syndrome; proteinuria; renal failure
Skin and Subcutaneous Tissue Disordersdry skin; hyperhidrosis; pemphigus foliaceus; pruritus; rash; rash pruritic; skin irritation; skin texture abnormal; skin wrinkling; urticaria

Read the entire FDA prescribing information for Thiola (Topronin Delayed-release Tablets)

© Thiola Patient Information is supplied by Cerner Multum, Inc. and Thiola Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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