Quinidine
Contraindicated
Textbook
Fatal ventricular arrhythmias.
Avoid coadministration or ensure strict potassium management.
Source: G&G 14e · p567
Drug reference
Trichlormethiazide
Thiazide diuretic (sulfonamide-derived) · Antihypertensive
START
1–2 mg PO once daily (morning)
TYPICAL MAX
4 mg/day
STOP IF
Severe electrolyte disturbance, gout flare, or pancreatitis
WATCH
K, Na, Ca, urate, glucose; BP / postural symptoms
CDSCO approvedSchedule HATC C03AA06
KDIGO 2024 + manufacturer label
- ONSET
- 1.5h · diuresis
- PEAK
- 6h · peak effect
- t½
- 4h · t½
- DURATION
- 1d · once-daily
EXCRETION
Renal — mainly unchanged
route + CYP
INTERACTIONS
12 major
incl. contraindicated
PREGNANCY
Avoid (oligohydramnios, neonatal effects).
FDA category + note
Top interactionssee all 12 →
- QuinidineContraindicatedTextbookG&G 14e · p567
- AmiodaroneSevereDatabaseDDInter
- Arsenic TrioxideSevereDatabaseDDInter
- DofetilideSevereDatabaseDDInter
Mechanism
Inhibits the Na+/Cl− cotransporter in the distal convoluted tubule, increasing sodium and water excretion; reduces extracellular volume and (chronically) peripheral vascular resistance — antihypertensive and diuretic.
Indications
HypertensionMild oedema (cardiac, hepatic, renal)Nephrogenic diabetes insipidus (paradoxical effect)
Dosing
- Adult
- 1–4 mg PO once daily; usual 2 mg/day.
- Pediatric
- 0.07 mg/kg/day (limited use).
- Renal adjustment
- Reduced efficacy CrCl <30; avoid in advanced impairment.
- Hepatic adjustment
- Caution; avoid in severe disease.
- Geriatric
- Start 1 mg; electrolyte risk.
- Max dose
- 4 mg/day
Pharmacokinetics
Onset
Diuresis 1–2 h
Peak effect
~6 h
Duration
~24 h
Half-life
~2–7 h
Bioavailability
Well absorbed orally
Protein binding
~30%
Metabolism
Minimal hepatic
Excretion
Renal (mainly unchanged)
Contraindications
- Anuria / severe renal impairment
- Severe hepatic impairment / hepatic coma risk
- Sulfonamide hypersensitivity
- Refractory hypokalaemia / hyponatraemia / hypercalcaemia
- Untreated Addison disease
Side effects
Common
HypokalaemiaHyponatraemiaHyperuricaemia / goutHyperglycaemiaPostural hypotensionPhotosensitivity
Serious
- Severe electrolyte disturbance / arrhythmia
- Severe sulfonamide allergy (rare SJS/TEN)
- Acute angle-closure glaucoma (rare)
- Pancreatitis
- Hypercalcaemia
Pregnancy & lactation
Pregnancy
Avoid (oligohydramnios, neonatal effects).
Lactation
Avoid (may reduce milk supply).
Drug interactions
Amiodarone
Severe
Database
Drug interaction classified as: synergy
Source: DDInter
Arsenic Trioxide
Severe
Database
Fatal ventricular arrhythmias.
Avoid coadministration or ensure strict potassium management.
Source: DDInter
Dofetilide
Severe
Database
Fatal ventricular arrhythmias.
Avoid coadministration or ensure strict potassium management.
Source: DDInter
Dolasetron
Severe
Database
Clinical effect not specified
Source: DDInter
Dronedarone
Severe
Database
Clinical effect not specified
Source: DDInter
Droperidol
Severe
Database
Clinical effect not specified
Source: DDInter
Lithium Carbonate
Severe
Database
Clinical effect not specified
Source: DDInter
Lithium
Severe
Database
Reduced lithium clearance
Monitor levels; reduce lithium
Source: Kimi deep-research + Cla · p378
Pimozide
Severe
Database
Clinical effect not specified
Source: DDInter
Tizanidine
Severe
Database
Clinical effect not specified
Source: DDInter
Ziprasidone
Severe
Database
Clinical effect not specified
Source: DDInter
Related guidelines
Ask House about Trichlormethiazide
Continue into a citation-backed clinical answer with the drug context already attached.
Sources: Katzung·Verified: 2026-05-20 · House clinical team·Cockpit curated: 2026-05-20