What amitriptyline is used for (common use)
Amitriptyline is a tricyclic antidepressant (TCA) registered in Australia for major depressive disorder. Clinicians also use it off-label for persistent pain and related conditions because it can aid sleep and modulate pain pathways. Common off-label uses include neuropathic pain (for example, diabetic neuropathy and postherpetic neuralgia), migraine prevention, fibromyalgia, temporomandibular joint disorder, irritable bowel syndrome, interstitial cystitis, and tension-type headache. By inhibiting serotonin and noradrenaline reuptake and exerting antihistamine effects, it may improve sleep continuity, mood, and pain tolerance.
Onset varies by condition. For depression, mood improvements often emerge after 2–4 weeks, with full benefit sometimes taking 6–8 weeks at an effective dose. For neuropathic pain and migraine prophylaxis, some people notice benefit within 1–2 weeks once a target dose is reached, though several weeks may be needed for best effect. Sedation is common, so dosing at bedtime is typical and can help when insomnia is also present.
Amitriptyline dosage and directions
A gradual titration approach helps balance benefit and tolerability. For depression, prescribers often start with 25–50 mg at night or in divided doses, then increase by 25–50 mg every few days as tolerated. Usual maintenance is 75–150 mg daily; some patients may need up to 200 mg under close supervision. Older adults usually begin at 10–25 mg nightly due to greater sensitivity to anticholinergic and cardiac effects.
For neuropathic pain, migraine prevention, and other off-label uses, lower doses often suffice. A common plan begins at 10–25 mg at night, increasing by 10–25 mg every 3–7 days to a typical range of 25–75 mg nightly. Using the lowest effective dose can reduce daytime drowsiness, dry mouth, constipation, and dizziness. If sedation is problematic, reducing the dose or taking it earlier in the evening may help.
Take amitriptyline consistently, preferably at bedtime, with or without food. Do not crush or chew tablets. If you miss a dose, follow the advice below. Do not stop suddenly; taper over weeks to minimise discontinuation symptoms such as nausea, headache, sleep disturbance, irritability, and flu-like feelings. Always individualise dosing with your prescriber, particularly when switching to or from other antidepressants to avoid interactions and serotonin syndrome risk.
Precautions and monitoring
Amitriptyline carries a boxed warning for increased risk of suicidal thoughts and behaviours in children, adolescents, and young adults, particularly early in treatment or during dose changes. Monitor mood, behaviour, and sleep closely, and seek prompt medical care for new or worsening depression, agitation, or suicidal thinking. Older adults are more prone to confusion, falls, anticholinergic effects, and cardiac conduction issues; conservative dosing and fall-prevention strategies are recommended.
Cardiac safety is important. TCAs can prolong PR, QRS, and QT intervals. People with cardiovascular disease, arrhythmias, or electrolyte disturbances may need baseline and follow-up ECGs, especially at higher doses. Avoid dehydration and correct low potassium or magnesium to reduce arrhythmia risk. Use caution with glaucoma (particularly angle-closure), urinary retention or BPH, severe constipation, seizure disorders, thyroid disease, and liver impairment. Alcohol and other sedatives can worsen drowsiness and impair coordination. Photosensitivity can occur—use sun protection if you notice increased sensitivity.
Contraindications
Do not use amitriptyline if you have hypersensitivity to TCAs, have had a recent myocardial infarction, or are taking a monoamine oxidase inhibitor (MAOI) or within 14 days of MAOI use (including linezolid or IV methylene blue) due to severe interaction risk and potential hypertensive crisis. It is contraindicated during the acute recovery phase after MI and should be avoided in uncontrolled narrow-angle glaucoma and severe urinary retention. Use extreme caution—or consider alternatives—if there is a history of significant arrhythmias or prolonged QT interval.
Possible amitriptyline side effects
Common effects reflect anticholinergic and antihistamine actions: dry mouth, constipation, blurred vision, urinary hesitancy, drowsiness, dizziness, increased appetite, and weight gain. Orthostatic hypotension may lead to lightheadedness or fainting on standing—rise slowly and stay hydrated. Daytime grogginess often improves with dose adjustments or earlier evening dosing. Sipping water, sugar-free gum, adding fibre, and maintaining hydration can help ease dryness and constipation.
Less common but important effects include confusion (particularly in older adults), sweating, tremor, sexual dysfunction, and photosensitivity. TCAs can affect cardiac conduction and rhythm; seek care for palpitations, fainting, chest pain, or shortness of breath. Rare but serious events include angle-closure glaucoma, significant urinary retention, seizures, severe constipation/ileus, and hepatotoxicity (watch for dark urine, jaundice, or right upper abdominal pain).
Serotonin syndrome can occur when combined with other serotonergic medicines. Warning signs include agitation, confusion, fever, sweating, rapid heart rate, tremor, muscle rigidity, and diarrhoea—seek emergency medical care if suspected. Report persistent or troublesome adverse effects to your healthcare professional; dose changes or alternative therapies may be appropriate.
Amitriptyline drug interactions
Avoid MAOIs and allow a 14-day washout. Combining amitriptyline with other serotonergic agents (SSRIs such as fluoxetine, sertraline; SNRIs; tramadol; linezolid; triptans; St John’s wort) can raise serotonin syndrome risk. Many SSRIs and bupropion inhibit CYP2D6, potentially increasing amitriptyline levels and side effects; fluoxetine and paroxetine are notable. If combinations are necessary, clinicians often reduce the TCA dose and monitor closely.
Additive sedation occurs with alcohol, benzodiazepines, opioids, sedating antihistamines, and sleep medicines. Anticholinergic burden increases with drugs such as oxybutynin, benztropine, or first-generation antihistamines, raising risks of constipation, confusion, and urinary retention. Medicines that prolong QT interval (certain antipsychotics, macrolide antibiotics, methadone, and some antiarrhythmics) may compound cardiac risk—consider ECG monitoring and alternatives when possible.
Cimetidine can increase TCA concentrations; dose adjustments may be needed. Carbamazepine can lower TCA levels. Blood pressure medicines may have altered effects due to TCA-induced noradrenaline reuptake blockade. Always give your prescriber and pharmacist a complete list of medicines and supplements so they can proactively check for interactions.
Missed dose
If you take amitriptyline once nightly and miss a dose, take it when remembered unless it is close to your usual wake time; if so, skip the missed dose and resume your regular schedule that evening. Do not double doses. For multiple-daily dosing, take the missed dose when remembered unless it is almost time for the next dose—then skip it. Keeping a consistent schedule helps maintain effectiveness and reduce side effects.
Overdose: what to know
An amitriptyline overdose is a medical emergency. Symptoms can include profound drowsiness, confusion, agitation, seizures, rapid or irregular heartbeat, low blood pressure, widened QRS on ECG, fever, dilated pupils, and pronounced anticholinergic signs (very dry mouth, flushed skin, urinary retention). If overdose is suspected in Australia, call 000 for emergency services or contact the Poisons Information Centre on 13 11 26 immediately. Do not induce vomiting unless advised by medical professionals. Hospital care may include cardiac monitoring, airway support, and IV sodium bicarbonate to treat cardiotoxicity.
Storage and handling
Store amitriptyline tablets below 25°C in a dry place away from light and moisture. Keep the medicine in the original child-resistant container and out of reach of children and pets. Do not use after the expiry date. For safe disposal in Australia, return unwanted medicines to your local pharmacy through the Return Unwanted Medicines (RUM) Project; do not flush medicines unless specifically instructed. The Therapeutic Goods Administration (TGA) and your pharmacist can provide disposal guidance.
Special populations: pregnancy, breastfeeding, and older adults
During pregnancy, amitriptyline may be considered when the expected benefits outweigh potential risks; discuss family planning and treatment goals with your clinician. Late-pregnancy exposure can lead to transient neonatal symptoms (jitteriness, feeding difficulties). During breastfeeding, small amounts pass into milk—monitor infants for excessive sleepiness or poor feeding. In older adults, use the lowest effective dose, monitor for cognitive changes, constipation, urinary retention, falls, and cardiac effects, and regularly review medicines to minimise anticholinergic burden.
Practical tips to improve tolerability
Start at night to make use of the sedative effect, and titrate slowly. Manage dry mouth with water, sugar-free gum, or saliva substitutes; constipation with fibre, fluids, and regular activity; and dizziness by rising slowly. Limit alcohol and avoid combining with other sedatives. Consider periodic weight and blood pressure checks. If daytime drowsiness persists, ask about earlier evening dosing or dose reduction. Never stop abruptly—plan a taper with your prescriber.
Australia sale and prescription policy: can you buy amitriptyline without prescription?
In Australia, amitriptyline is a Schedule 4 (Prescription Only) medicine. Australian law requires a valid prescription from an authorised prescriber (for example, a GP, psychiatrist, or nurse practitioner) for it to be dispensed. Buying or selling prescription medicines without a prescription is illegal and unsafe. Avoid websites that offer amitriptyline without a prescription—these products may be counterfeit, subpotent, contaminated, or dangerous. For legal, safe access, use Australian-registered pharmacies and consider telehealth with an Australian prescriber, including ePrescriptions sent directly to your chosen pharmacy.
Australian health services can provide structured, lawful care pathways that include assessment, monitoring, and prescriptions when clinically appropriate; however, there is no legitimate program in Australia that supplies amitriptyline without a valid prescription. To reduce costs, ask about PBS-subsidised options, generic brands, concessional co-payments, Safety Net thresholds, and longer dispensing intervals where eligible (for example, 60-day dispensing on selected items). When using online pharmacies, ensure they are Australian-registered: check pharmacy premises registration with your state or territory pharmacy authority (e.g., Victorian Pharmacy Authority, Pharmacy Council of NSW) and confirm pharmacist registration via Ahpra. Prefer services that require a valid Australian prescription and provide pharmacist counselling.
