Comprehensive medication guide to Terrell including estimated pricing, availability information, side effects, and how to find it in stock at your local pharmacy.
Estimated Insurance Pricing
Anesthetic cost is bundled into facility charges; patients do not pay for isoflurane separately. Coverage depends on plan deductible, coinsurance, and network status of surgical facility and anesthesia providers.
Estimated Cash Pricing
$40–$150 per 100 mL–250 mL bottle through medical distributors; priced for facility procurement, not retail pharmacy dispensing. No GoodRx or coupon pricing applies.
Medfinder Findability Score
72/100
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Terrell is the brand name for isoflurane USP, a general inhalational anesthetic manufactured by Piramal Critical Care, Inc. FDA-approved since 1979, Terrell is a clear, colorless, nonflammable liquid that is vaporized and inhaled to induce and maintain general anesthesia during surgical procedures.
Terrell is available in 100 mL and 250 mL amber glass bottles containing 99.9% isoflurane. It must be delivered through a calibrated isoflurane-specific vaporizer connected to an anesthesia machine in a facility equipped with monitoring and resuscitation equipment. It is not available at retail pharmacies.
Terrell is not a controlled substance under DEA scheduling, but it requires a prescription and can only be administered by trained anesthesia professionals — anesthesiologists (MD/DO), certified registered nurse anesthetists (CRNAs), and anesthesiologist assistants (AAs). It is used in hospitals, ambulatory surgical centers, and critical care settings.
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Terrell (isoflurane) produces general anesthesia by acting on the central nervous system through several mechanisms. Most importantly, it enhances GABA-A receptor activity — amplifying the brain's main inhibitory neurotransmitter system — and blocks NMDA receptors involved in consciousness and pain signaling. This combination suppresses neural activity across the brain, producing unconsciousness, amnesia, and reduced pain perception.
When inhaled, isoflurane crosses from the lungs into the bloodstream and travels to the brain, where it accumulates in lipid-rich tissue. The depth of anesthesia is directly controlled by adjusting the inhaled concentration. The MAC (minimum alveolar concentration) for isoflurane is approximately 1.15% in a 40-year-old adult — this is a measure of potency, representing the concentration at which 50% of patients won't respond to a surgical incision.
Isoflurane is eliminated primarily through exhalation — less than 0.2% is metabolized by the liver. When the gas is discontinued after surgery, isoflurane leaves the brain in reverse and is exhaled, allowing the patient to wake up. The level of anesthesia can be changed rapidly, giving anesthesia teams precise control throughout the procedure.
99.9% (1 mL/mL) — Inhalation liquid (100 mL bottle)
Delivered via calibrated isoflurane-specific vaporizer. Induction: 1.5–3.0%; Maintenance: 1.0–2.5% with N2O or 1.5–3.5% with O2 alone.
99.9% (1 mL/mL) — Inhalation liquid (250 mL bottle)
Larger bottle format for higher-volume facilities. Same concentration and dosing protocols as 100 mL bottle.
Terrell (isoflurane) is generally available through hospital and surgical-center supply channels, and no active national shortage is currently listed on the FDA or ASHP databases as of 2026. However, the global isoflurane market is small and concentrated, with limited manufacturing redundancy. This makes the supply chain vulnerable to localized disruptions from manufacturing delays, distributor allocation changes, or demand spikes.
Individual hospitals and ambulatory surgical centers may encounter availability challenges without a formal shortage being declared. Facilities are advised to maintain multi-distributor relationships, a 30-day safety stock, and backup anesthetic protocols. The isoflurane market is also shared with veterinary medicine, and demand competition between sectors can tighten supply.
If you're a patient who needs help locating other prescription medications around your surgical procedure, medfinder can call pharmacies near you to check availability and text you the results.
Terrell (isoflurane) is not a controlled substance, so it does not require DEA registration to prescribe. However, the FDA prescribing information requires that it be administered only by persons trained in the administration of general anesthesia — meaning it is restricted to use in clinical settings by qualified anesthesia professionals.
Qualified providers who can administer Terrell:
Terrell is not available via telehealth. It must be administered in-person in a procedural setting equipped with an isoflurane-compatible vaporizer, anesthesia machine, patient monitoring systems, and full resuscitation capability. Patients do not choose or request this medication directly — it is selected by the anesthesia team based on clinical assessment.
No. Terrell (isoflurane, USP) is not a controlled substance under the DEA Controlled Substances Act. It has no DEA schedule. Isoflurane does not have the abuse or addiction potential associated with opioids, benzodiazepines, or other scheduled drugs.
While not scheduled, Terrell is strictly a prescription drug that requires administration by a trained anesthesia professional using specialized equipment. It cannot be self-administered and is not available through retail pharmacy channels. The DailyMed label for Terrell confirms its DEA Schedule as "None" and marketing status as an Abbreviated New Drug Application (ANDA) product.
The following side effects occur in more than 5% of patients:
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Sevoflurane (Sojourn, Ultane)
Most widely used inhaled anesthetic in the U.S. Preferred for pediatric and outpatient cases due to smoother, less pungent induction. MAC ~2.0% vs. isoflurane's ~1.15%.
Desflurane (Suprane)
Fastest emergence of any inhaled anesthetic due to very low blood-gas solubility. Preferred for long surgeries and obese patients. Requires specialized heated vaporizer. High global warming potential.
Propofol (Diprivan)
IV anesthetic used for total intravenous anesthesia (TIVA). No vaporizer required; lower PONV rates. Safe option when inhaled agents are unavailable or contraindicated (e.g., MH susceptibility).
Ketamine
Dissociative IV/IM anesthetic. Maintains airway reflexes; useful in resource-limited settings and pediatric cases. Can cause emergence delirium at full anesthetic doses.
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Nitrous Oxide (N2O)
moderateReduces MAC of isoflurane by approximately 50-60% when used at 70% concentration. Beneficial interaction intentionally used in balanced anesthetic techniques. Dose adjustment required.
Opioids (fentanyl, morphine, remifentanil)
moderateDecrease MAC of isoflurane and potentiate respiratory depression. Additive CNS and respiratory depressant effects. Commonly co-administered; requires careful dose coordination and ventilatory monitoring.
Neuromuscular Blocking Agents (rocuronium, vecuronium, succinylcholine)
majorIsoflurane markedly potentiates muscle relaxation from all neuromuscular blockers, especially nondepolarizing agents. Lower doses required; risk of prolonged paralysis if unadjusted. Neuromuscular monitoring essential.
QT-Prolonging Medications (amiodarone, antipsychotics, fluoroquinolones)
majorAdditive QT interval prolongation risk, potentially leading to torsade de pointes arrhythmia. ECG monitoring indicated. Includes antiarrhythmics, certain antipsychotics, and some antibiotics.
CNS Depressants (benzodiazepines, barbiturates, alcohol)
moderateAdditive CNS and respiratory depression. May increase anesthetic requirements in chronic users (alcohol, opioids) or decrease them in acute intoxication. Full disclosure of substance use required pre-operatively.
Hepatotoxic Agents (isoniazid, methotrexate, high-dose acetaminophen)
moderateAdditive hepatotoxic risk. Clinical judgment required in patients with pre-existing hepatic conditions or concurrent use of hepatotoxic drugs. Liver function monitoring post-operatively may be indicated.
Terrell (isoflurane, USP) has been a cornerstone of general anesthesia practice for over four decades. With its well-characterized safety profile, rapid adjustability, and global track record, it remains an important option in the anesthesia provider's toolkit — even as newer agents like sevoflurane have taken a larger share of the market in high-income countries.
For facilities, the key is supply chain preparedness — maintaining safety stock, multi-distributor relationships, and backup clinical protocols. For patients, understanding what Terrell is, how it works, and what to tell your anesthesia team about your medical history and medications will help ensure the safest possible experience.
If you need help finding any of your other prescription medications at a pharmacy near you — whether before or after surgery — medfinder is here to help. We call pharmacies near you, check availability, and text you the results.
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Our medication guides are researched and written to help patients make informed decisions. All content is reviewed for accuracy and updated regularly. Learn more about our standards
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