Tolazoline: Uses, Dosage, Side Effects & Warnings | DrugsAtlas
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DRUG NAME: Tolazoline
Therapeutic Class: Non-selective α-adrenergic antagonist
Subclass: Vasodilator
Speciality: Neonatology
Schedule (India): Schedule H
Route(s): Intravenous
Formulations Available in India:
• Injection 25 mg/mL (as hydrochloride), 10 mL ampoules
• Injection 25 mg/mL (as hydrochloride), 10 mL ampoules
INDICATIONS + DOSING — FOR CLINICIAN USE ONLY
Primary Indications (Approved / Standard in India)
1. Persistent Pulmonary Hypertension of the Newborn (PPHN) — Specialist Use Only
| Parameter | Recommendation |
|---|---|
| Starting dose | 1 mg/kg IV slowly over 10 minutes |
| Titration | May repeat bolus every 6–8 hours if needed, or initiate continuous infusion |
| Usual maintenance dose | 0.5–1.5 mg/kg/hour by continuous IV infusion |
| Maximum dose | 4 mg/kg/day |
Clinical Notes:
- Restricted to NICU settings with invasive haemodynamic monitoring
- Significant hypotension risk — ensure adequate preload before administration
- Exercise caution in neonates with co-existing congenital cardiac defects
- Now largely superseded by inhaled nitric oxide and sildenafil in most tertiary centres
2. Peripheral Vasospastic Disorders (e.g., Raynaud's phenomenon, acrocyanosis) — Limited Use
| Parameter | Recommendation |
|---|---|
| Starting dose | 10–25 mg IV slowly over 10 minutes |
| Titration | May repeat once after 30 minutes if no response |
| Usual maintenance dose | Not applicable — acute use only |
| Maximum dose | 50 mg per episode |
Clinical Notes:
- Largely obsolete indication in current Indian practice
- Calcium channel blockers (nifedipine) and prostacyclin analogues are now preferred
- Reserved for refractory cases under specialist supervision only
Secondary Indications – Adults (Off-label, if any)
NOT RECOMMENDED — This agent is considered outdated for adult indications. No validated off-label use in current Indian clinical practice.
PAEDIATRIC DOSING (Specialist Only)
Primary Indications
Persistent Pulmonary Hypertension of the Newborn (PPHN)
Age Group: Neonates ≥34 weeks gestational age only
| Weight-based Dosage | Administration |
|---|---|
| 1 mg/kg IV bolus | Administer slowly over 10 minutes |
| 0.5–1.5 mg/kg/hour | Continuous IV infusion |
| Parameter | Value |
|---|---|
| Maximum daily dose | 4 mg/kg/day |
| Minimum age/gestation | ≥34 weeks gestation |
| Setting | NICU only |
Safety Monitoring:
- Continuous blood pressure monitoring (arterial line preferred)
- Continuous ECG monitoring
- Pulse oximetry / arterial oxygenation
- Hourly urine output assessment
- Watch for signs of systemic hypotension or worsening shunting
⚠️ Not recommended in infants, children, or adolescents outside the neonatal period.
Secondary Indications – Paediatric Doses (Off-label, if any)
No validated off-label indications in paediatric population beyond neonatal PPHN.
Use restricted to NICU setting with neonatology specialist oversight only.
RENAL ADJUSTMENT
| Renal Status | Recommendation |
|---|---|
| Mild–Moderate impairment | No specific eGFR-based adjustment established; use with caution |
| Severe impairment | Risk of drug accumulation and prolonged vasodilatory effects; avoid if possible |
| Haemodialysis | No specific data available; exercise caution |
Monitoring: Close blood pressure surveillance required in all degrees of renal impairment.
HEPATIC ADJUSTMENT
| Hepatic Status | Recommendation |
|---|---|
| Mild impairment | No standard dose adjustment; monitor for enhanced hypotensive response |
| Moderate impairment | Use with caution; anticipate exaggerated effects |
| Severe impairment | Avoid or use with extreme caution; unpredictable metabolism; specialist decision only |
CONTRAINDICATIONS
- Hypotension or hypovolaemia (uncorrected)
- Known hypersensitivity to tolazoline or any excipient
- Severe coronary artery disease
- Pre-existing cardiac arrhythmias (especially in neonates)
- Active gastrointestinal bleeding (tolazoline may stimulate gastric acid secretion)
CAUTIONS
- Mandatory continuous cardiac monitoring during IV administration
- Risk of severe hypotension and reflex tachycardia
- Caution in neonates with left-to-right cardiac shunts (may worsen shunting)
- Avoid extravasation — causes local tissue irritation and necrosis
- Gastric acid hypersecretion — risk of GI bleeding, particularly in stressed neonates
- Ensure secure central IV access where possible
- Preload optimisation essential before bolus administration
PREGNANCY
| Parameter | Information |
|---|---|
| Risk category | Category C (Risk not ruled out) |
| Overall safety | Not recommended; inadequate human safety data |
| Preferred alternatives | For pregnancy-related hypertension/vasospasm: labetalol, nifedipine, hydralazine (as per Indian obstetric protocols) |
| When it may be used | Only if no safer alternative available and benefit clearly outweighs risk; specialist input essential |
| Monitoring | Maternal blood pressure, fetal heart rate monitoring if used |
LACTATION
| Parameter | Information |
|---|---|
| Compatibility | Unknown; no human lactation data available |
| Expected levels in milk | Theoretical low levels (lipophilic compound) |
| Preferred alternatives | Avoid use; nifedipine preferred if vasodilator needed postpartum |
| What to monitor in infant | Feeding difficulties, irritability, hypotension signs (if inadvertently exposed) |
ELDERLY
| Parameter | Recommendation |
|---|---|
| Recommended starting dose | Not routinely indicated in elderly |
| Titration | Slower titration if ever used |
| Special risks | Exaggerated hypotensive response, syncope, falls, cardiac arrhythmias |
| Overall recommendation | Avoid routine use; safer alternatives available for vasospastic conditions |
MAJOR DRUG INTERACTIONS
| Interacting Drug/Class | Effect | Recommendation |
|---|---|---|
| Sympathomimetics (epinephrine, dopamine, norepinephrine) | Antagonistic effects; reduced efficacy of both agents | Avoid concurrent use; reassess therapeutic goals |
| Phosphodiesterase-5 inhibitors (sildenafil, tadalafil) | Marked potentiation of vasodilation; severe hypotension risk | Avoid combination |
| Antihypertensives (all classes) | Additive hypotension | Use with extreme caution; close BP monitoring |
MODERATE DRUG INTERACTIONS
| Interacting Drug/Class | Effect | Recommendation |
|---|---|---|
| Diuretics | Enhanced hypotensive effect due to volume depletion | Monitor BP; ensure adequate hydration |
| Beta-blockers | Risk of bradycardia and AV block (reflex compensation impaired) | Monitor heart rate and rhythm |
| Digitalis glycosides | Increased arrhythmia risk | ECG monitoring advised |
| H2-receptor antagonists / PPIs | May partially offset tolazoline-induced gastric acid secretion | Consider prophylactic use in neonates |
COMMON ADVERSE EFFECTS
- Hypotension
- Flushing
- Tachycardia
- Nausea and vomiting
- Increased gastric acid secretion
- Injection site irritation
SERIOUS ADVERSE EFFECTS
- Severe hypotension and cardiovascular collapse
- Cardiac arrhythmias (particularly in neonates)
- Gastrointestinal haemorrhage (due to gastric acid hypersecretion)
- Extravasation injury with tissue necrosis
- Pulmonary oedema (in fluid-overloaded neonates)
- Oliguria / acute kidney injury (secondary to hypoperfusion)
MONITORING REQUIREMENTS
| Timing | Parameters |
|---|---|
| Baseline | Blood pressure, heart rate, oxygen saturation, renal function, haematocrit (neonates) |
| During therapy | Continuous ECG, continuous invasive BP monitoring (mandatory in neonates), hourly urine output |
| After dose changes | Reassess haemodynamic status within 15–30 minutes of bolus/titration |
| Long-term | Not applicable — short-term use only |
Additional:
- Monitor for signs of GI bleeding (occult blood, abdominal distension)
- Assess for over-perfusion or worsening shunting in neonates with cardiac defects
BRANDS AVAILABLE IN INDIA
- Tolazoline Hydrochloride Injection (generic)
- Vasonite (limited availability)
- Availability primarily through tertiary hospital pharmacy procurement networks; rarely stocked in retail pharmacies
PRICE RANGE (INR)
| Formulation | Price Range |
|---|---|
| Injection 25 mg/mL, 10 mL ampoule | ₹150–300 per ampoule |
Note: Tertiary care supply only; request-based procurement in most centres. Not listed under NLEM or NPPA price control.
CLINICAL PEARLS
- Tolazoline is largely obsolete for PPHN management; inhaled nitric oxide and oral/IV sildenafil are now first-line in most Indian tertiary NICUs
- If tolazoline is used, ensure adequate intravascular volume before bolus to minimise hypotension
- Always use central venous access if possible to prevent extravasation injury
- Prophylactic H2-blocker or PPI may reduce risk of GI bleeding in neonates receiving tolazoline
- Keep vasopressors readily available during administration
- Not suitable for peripheral vasospastic disorders — nifedipine or iloprost are preferred in current Indian practice
TAGS
Tolazoline; PPHN; neonatal care; vasodilator; alpha-blocker; IV drug only; Schedule H; hypotension risk; NICU; obsolete in adults
VERSION
RxIndia v0.3 — 18 Feb 2026
REFERENCES
- IP/NFI
- CDSCO product insert
- AIIMS Neonatology Protocols
- NNF (National Neonatology Forum) Guidelines
- API Textbook of Medicine
- WHO EML (supportive reference for neonatal use)
- Goodman & Gilman's The Pharmacological Basis of Therapeutics
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Clinical Responsibility
This platform is designed strictly for healthcare professionals. Data provided is synthesized from authoritative pharmacological sources and clinical registries. Do not use for consumer medical decisions. Always verify critical dosing and contraindications with official institutional protocols and peer-reviewed journals.
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