Telmisartan and Hydrochlorothiazide side effects: what 2,354 FDA adverse event reports show
Drug class
Angiotensin 2 Receptor Blocker
Label matched
Telmisartan (Telmisartan)
Who reports
2,354 reports · 63% serious · 145 with death outcome · 63% female
Used for
Telmisartan tablets are an angiotensin II receptor blocker (ARB) indicated for: Treatment of hypertension, to lower blood pressure. Lowering blood pressure reduces the risk of fatal and nonfatal cardiovascular events, primarily strokes and myocardial infarctions. (1.1) Cardiovascular (CV) risk reduction in patients unable to take ACE inhibitors.
What it is
Telmisartan is a non-peptide angiotensin II receptor (type AT 1 ) antagonist. Telmisartan is chemically described as 4'-[(1,4'-dimethyl-2'-propyl [2,6'-bi-1H-benzimidazol]-1'-yl)methyl]-[1,1'-biphenyl]-2-carboxylic acid.
Boxed warning
FETAL TOXICITY When pregnancy is detected, discontinue telmisartan as soon as possible [see Warnings and Precautions (5.1) and Use in Specific Populations (8.1) ]. Drugs that act directly on the renin-angiotensin system can cause injury and death to the developing fetus [see Warnings and Precautions (5.1) and Use in Specific Populations (8.1) ].
Causality screen of the 28 strongest signals
What the badges mean
- Labeled — boxed warning The term (or its clinical synonym) appears in the FDA boxed warning: causality is regulator-recognised and considered serious.
- Labeled adverse reaction The exact term appears in the label's warnings or adverse-reactions sections: a known, expected effect. The FAERS signal confirms the label rather than discovering anything.
- Labeled (related wording) The label describes this effect under different wording (e.g. 'neutropenia' for 'neutrophil count decreased'). Treated as known.
- Likely indication confounding The term appears in the label's indications: reports probably describe the disease being treated (or its progression), not a drug effect. Classic confounding by indication.
- Lab value / disease marker A laboratory result, investigation or disease-activity marker (antibody positive, CRP abnormal, swollen joint count) not described in the label. These usually mirror the monitored disease or testing protocol rather than a drug effect; not screened further.
- Not in label — unassessed Not found in the label text, not an artifact pattern. This is a genuine candidate for a formal causality assessment (Bradford Hill / WHO-UMC); it has NOT had one here.
Strongest disproportionality signals
Flagged terms (PRR ≥ 2, χ² ≥ 4, n ≥ 10), ranked by PRR; infinite PRRs (no comparator reports) excluded. The EBGM column is a second, shrinkage-based estimate (MGPS) with its 5th percentile EB05 and the BCPNN IC025; a pair flagged by PRR alone is marked PRR-only and should be read as fragile. The strata column recomputes the PRR on serious reports only and flags pairs whose reports are unusually skewed by sex or come mostly from consumers rather than clinicians. 49 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Hypertensive crisis | 21 | 16.8 11.0–25.7ROR 16.9 · χ² 296 / p 1e-66 | 16.3 EB05 11.0 · IC025 +2.9 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious PRR 15.5 | no trial data cached |
| Sinus bradycardia | 11 | 10.1 5.6–18.3ROR 10.2 · χ² 82 / p 9e-20 | 8.2 EB05 4.5 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | serious PRR 9.6 | no trial data cached |
| Coronary artery occlusion | 14 | 9.1 5.4–15.3ROR 9.1 · χ² 92 / p 4e-22 | 7.6 EB05 4.6 · IC025 +1.9 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious PRR 8.4 | no trial data cached |
| Blood pressure abnormal | 19 | 8.6 5.5–13.4ROR 8.6 · χ² 119 / p 5e-28 | 7.5 EB05 4.9 · IC025 +2.1 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious PRR 6.6 | no trial data cached |
| Blood sodium decreased | 18 | 8.5 5.4–13.5ROR 8.6 · χ² 112 / p 2e-26 | 7.4 EB05 4.8 · IC025 +2.0 3/3 methods agree | Likely indication confounding term in indications | serious PRR 7.4 | no trial data cached |
| Tendon rupture (torn tendon) | 10 | 7.2 3.9–13.4ROR 7.2 · χ² 47 / p 3e-12 | 5.6 EB05 3.2 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 7.3 | no trial data cached |
| Hyponatraemia (low sodium) | 43 | 6.8 5.1–9.2ROR 6.9 · χ² 208 / p 2e-47 | 6.4 EB05 4.9 · IC025 +2.2 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 6.0 · 92% clinician | no trial data cached |
| Sleep apnoea syndrome | 14 | 6.5 3.9–11.0ROR 6.6 · χ² 60 / p 5e-15 | 5.5 EB05 3.5 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 6.1 | no trial data cached |
| Blood potassium decreased | 22 | 6.5 4.3–9.9ROR 6.6 · χ² 97 / p 3e-23 | 5.8 EB05 4.0 · IC025 +1.8 3/3 methods agree | Lab value / disease marker | serious PRR 5.2 | no trial data cached |
| Renal failure acute | 31 | 6.4 4.5–9.1ROR 6.5 · χ² 137 / p 7e-32 | 5.9 EB05 4.3 · IC025 +2.0 3/3 methods agree | Labeled (related wording) related wording | serious PRR 6.0 | no trial data cached |
| Blood pressure increased | 104 | 6.0 5.0–7.3ROR 6.3 · χ² 436 / p 4e-97 | 5.9 EB05 5.0 · IC025 +2.2 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 3.9 | no trial data cached |
| Pollakiuria (frequent urination) | 24 | 5.1 3.4–7.6ROR 5.2 · χ² 76 / p 1e-18 | 4.7 EB05 3.3 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 4.7 | no trial data cached |
| Orthostatic hypotension (dizziness on standing) | 10 | 5.1 2.8–9.5ROR 5.1 · χ² 29 / p 4e-8 | 4.2 EB05 2.5 · IC025 +1.0 3/3 methods agree | Not in label — unassessed | serious PRR 4.8 | no trial data cached |
| Gout | 10 | 5.0 2.7–9.2ROR 5.0 · χ² 28 / p 7e-8 | 4.1 EB05 2.4 · IC025 +1.0 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 2.1 | no trial data cached |
| Erectile dysfunction | 13 | 4.5 2.6–7.7ROR 4.5 · χ² 32 / p 8e-9 | 3.9 EB05 2.5 · IC025 +1.1 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 1.8 | no trial data cached |
| Arrhythmia | 24 | 4.5 3.0–6.7ROR 4.5 · χ² 62 / p 2e-15 | 4.2 EB05 3.0 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 4.3 | no trial data cached |
| Lactic acidosis | 15 | 4.2 2.5–6.9ROR 4.2 · χ² 33 / p 5e-9 | 3.7 EB05 2.4 · IC025 +1.0 3/3 methods agree | Not in label — unassessed | serious PRR 3.8 | no trial data cached |
| Blood pressure fluctuation | 11 | 4.1 2.3–7.3ROR 4.1 · χ² 23 / p 1e-6 | 3.6 EB05 2.1 · IC025 +0.8 3/3 methods agree | Lab value / disease marker | serious PRR 3.9 | no trial data cached |
| Transient ischaemic attack (mini-stroke) | 15 | 3.9 2.4–6.5ROR 4.0 · χ² 30 / p 2e-8 | 3.6 EB05 2.3 · IC025 +1.0 3/3 methods agree | Likely indication confounding term in indications | serious PRR 3.4 | no trial data cached |
| Heart rate irregular | 10 | 3.9 2.1–7.3ROR 3.9 · χ² 19 / p 7e-6 | 3.4 EB05 2.0 · IC025 +0.7 3/3 methods agree | Not in label — unassessed | serious PRR 1.9 | no trial data cached |
| Glycosylated haemoglobin increased | 11 | 3.9 2.2–7.0ROR 3.9 · χ² 21 / p 2e-6 | 3.4 EB05 2.1 · IC025 +0.8 3/3 methods agree | Lab value / disease marker | serious PRR 7.4 | no trial data cached |
| Haematoma | 11 | 3.8 2.1–6.8ROR 3.8 · χ² 20 / p 5e-6 | 3.3 EB05 2.0 · IC025 +0.7 3/3 methods agree | Not in label — unassessed | serious PRR 3.8 | no trial data cached |
| Lip swelling | 12 | 3.2 1.8–5.7ROR 3.2 · χ² 16 / p 3e-5 | 2.9 EB05 1.8 · IC025 +0.6 | Not in label — unassessed | serious PRR 2.4 | no trial data cached |
| Suicide attempt | 20 | 2.9 1.9–4.5ROR 2.9 · χ² 24 / p 6e-7 | 2.8 EB05 1.9 · IC025 +0.7 | Not in label — unassessed | serious PRR 2.7 | no trial data cached |
| Blindness | 13 | 2.8 1.7–4.9ROR 2.9 · χ² 14 / p 1e-4 | 2.7 EB05 1.7 · IC025 +0.5 | Not in label — unassessed | serious PRR 2.5 | no trial data cached |
| Convulsion (seizure) | 16 | 2.5 1.5–4.0ROR 2.5 · χ² 12 / p 2e-4 | 2.4 EB05 1.6 · IC025 +0.4 | Not in label — unassessed | serious PRR 2.3 | no trial data cached |
| Myocardial infarction (heart attack) | 48 | 2.4 1.8–3.2ROR 2.5 · χ² 39 / p 2e-10 | 2.4 EB05 1.9 · IC025 +0.8 | Likely indication confounding term in indications | serious PRR 2.3 | no trial data cached |
| Blood glucose decreased | 12 | 2.2 1.3–3.9ROR 2.2 · χ² 7 / p 0.004 | 2.1 EB05 1.3 · IC025 +0.1 | Labeled (related wording) related wording | serious PRR 1.7 | no trial data cached |
Trial evidence (ClinicalTrials.gov)
Most frequently reported reactions
By raw co-report count, regardless of disproportionality. Common terms here are often the illness itself or generic outcomes.
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Blood pressure increased | 104 | 6.0 5.0–7.3ROR 6.3 · χ² 436 / p 4e-97 | 5.9 EB05 5.0 · IC025 +2.2 3/3 methods agree | Labeled — boxed warning synonym match | serious PRR 3.9 | no trial data cached |
| Myocardial infarction (heart attack) | 48 | 2.4 1.8–3.2ROR 2.5 · χ² 39 / p 2e-10 | 2.4 EB05 1.9 · IC025 +0.8 | Likely indication confounding term in indications | serious PRR 2.3 | no trial data cached |
| Hyponatraemia (low sodium) | 43 | 6.8 5.1–9.2ROR 6.9 · χ² 208 / p 2e-47 | 6.4 EB05 4.9 · IC025 +2.2 3/3 methods agree | Labeled adverse reaction exact term | serious PRR 6.0 · 92% clinician | no trial data cached |
| Blood glucose increased | 40 | 1.9 1.4–2.6ROR 1.9 · χ² 16 / p 3e-5 | 1.9 EB05 1.4 · IC025 +0.4 | Lab value / disease marker | serious PRR 2.1 | no trial data cached |
| Renal failure acute | 31 | 6.4 4.5–9.1ROR 6.5 · χ² 137 / p 7e-32 | 5.9 EB05 4.3 · IC025 +2.0 3/3 methods agree | Labeled (related wording) related wording | serious PRR 6.0 | no trial data cached |
| Arrhythmia | 24 | 4.5 3.0–6.7ROR 4.5 · χ² 62 / p 2e-15 | 4.2 EB05 3.0 · IC025 +1.4 3/3 methods agree | Not in label — unassessed | serious PRR 4.3 | no trial data cached |
| Pollakiuria (frequent urination) | 24 | 5.1 3.4–7.6ROR 5.2 · χ² 76 / p 1e-18 | 4.7 EB05 3.3 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | serious PRR 4.7 | no trial data cached |
| Blood potassium decreased | 22 | 6.5 4.3–9.9ROR 6.6 · χ² 97 / p 3e-23 | 5.8 EB05 4.0 · IC025 +1.8 3/3 methods agree | Lab value / disease marker | serious PRR 5.2 | no trial data cached |
| Hypertensive crisis | 21 | 16.8 11.0–25.7ROR 16.9 · χ² 296 / p 1e-66 | 16.3 EB05 11.0 · IC025 +2.9 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious PRR 15.5 | no trial data cached |
| Suicide attempt | 20 | 2.9 1.9–4.5ROR 2.9 · χ² 24 / p 6e-7 | 2.8 EB05 1.9 · IC025 +0.7 | Not in label — unassessed | serious PRR 2.7 | no trial data cached |
| Blood pressure abnormal | 19 | 8.6 5.5–13.4ROR 8.6 · χ² 119 / p 5e-28 | 7.5 EB05 4.9 · IC025 +2.1 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious PRR 6.6 | no trial data cached |
| Blood sodium decreased | 18 | 8.5 5.4–13.5ROR 8.6 · χ² 112 / p 2e-26 | 7.4 EB05 4.8 · IC025 +2.0 3/3 methods agree | Likely indication confounding term in indications | serious PRR 7.4 | no trial data cached |
| Convulsion (seizure) | 16 | 2.5 1.5–4.0ROR 2.5 · χ² 12 / p 2e-4 | 2.4 EB05 1.6 · IC025 +0.4 | Not in label — unassessed | serious PRR 2.3 | no trial data cached |
| Transient ischaemic attack (mini-stroke) | 15 | 3.9 2.4–6.5ROR 4.0 · χ² 30 / p 2e-8 | 3.6 EB05 2.3 · IC025 +1.0 3/3 methods agree | Likely indication confounding term in indications | serious PRR 3.4 | no trial data cached |
| Lactic acidosis | 15 | 4.2 2.5–6.9ROR 4.2 · χ² 33 / p 5e-9 | 3.7 EB05 2.4 · IC025 +1.0 3/3 methods agree | Not in label — unassessed | serious PRR 3.8 | no trial data cached |
Unlabeled candidate signals
These flagged terms were not found in the FDA label text and do not match an artifact pattern. They are the pairs that would merit a structured assessment (temporality, dose-response, biological plausibility, consistency across databases, trial or cohort evidence). The screen has not done that; string-matching misses label wording, and a strong PRR can still be stimulated reporting, co-medication, or the disease itself.
- Pollakiuria — n=24, PRR 5.1
- Arrhythmia — n=24, PRR 4.5
- Suicide attempt — n=20, PRR 2.9
✓ A hand-written Bradford Hill causality assessment exists for this drug: Hydrochlorothiazide (thiazides) ↔ Hyponatraemia.
Want to assess one of these properly? The runbook describes the Bradford Hill / trial-evidence workflow used on the assessment page, and handoff_top1000_signals.csv lists the strongest unassessed pairs across all drugs.
Common questions
What are the most reported side effects of Telmisartan and Hydrochlorothiazide?
In FDA FAERS, the most frequently co-reported reaction terms for Telmisartan and Hydrochlorothiazide are blood pressure increased, myocardial infarction, hyponatraemia, blood glucose increased, renal failure acute, arrhythmia. These are report counts, not rates: FAERS has no denominator, reporting is voluntary and uneven, and a term can be reported because of the illness being treated rather than the drug.
Does Telmisartan and Hydrochlorothiazide have an FDA boxed warning?
Yes. The current FDA label carries a boxed warning: FETAL TOXICITY When pregnancy is detected, discontinue telmisartan as soon as possible [see Warnings and Precautions (5.1) and Use in Specific Populations (8.1) ]. Drugs that act directly on the renin-angiotensin system can cause injury and death to the developing fetus [see Warnings and Precautions (5.1) and Use in Specific Populations (8.1) ].
Do FAERS signals prove that Telmisartan and Hydrochlorothiazide causes these side effects?
No. A disproportionality signal (PRR, ROR) means a reaction is reported more often with this drug than with others in the database. That can reflect a real effect, but also the disease being treated, stimulated reporting after news or litigation, co-medications, or how reports are coded. Causality needs temporality, dose-response, biological plausibility, consistency across data sources and, ideally, trial or cohort evidence. This page screens each term against the FDA label and ClinicalTrials.gov results; it does not establish causation.
Sources & methods
- FDA label via openFDA (set ID 20a60231-64f0-4751-aa81-6c0e64334179, effective 20230930; matched on
openfda.generic_name.exact:"TELMISARTAN") - Bayesian shrinkage measures computed offline over all 1,317,300 cached pairs: BCPNN information component (IC, with Norén closed-form IC025) and MGPS empirical-Bayes geometric mean (EBGM, EB05) with a two-component gamma prior fitted by maximum marginal likelihood (α₁=0.57, β₁=0.02, α₂=1.42, β₂=0.70, w=0.17); unstratified
- FAERS pair statistics from the OpenPV build of 2026-09-14 (openFDA
count=aggregation, fieldpatient.drug.openfda.generic_name.exact, 77 reaction terms, min 3 co-reports); PRR/ROR with 95% CI, chi-square with Yates correction - Serious-only and stratified counts (serious:1, patient.patientsex, primarysource.qualification) from openFDA count queries; serious-only PRR uses the drug serious report total and the term global serious total (N_serious=11,882,979); strata shown only when n ≥ 20
- Seriousness and sex counts from openFDA
count=serious,patient.patientsex,seriousnessdeath
Page generated 2026-10-08. Label and PubChem text are retrieved automatically and may lag the current label; always check the current prescribing information. OpenPV is a beta research tool of the Open Source Medicine Foundation.