01Purpose and principlesWhat the treatment does and how it fits into care.
Medication begins with a shared treatment question. Confirm that an antidepressant matches severity and informed preference. Review previous benefit, adverse effects and withdrawal; family response may inform but does not determine choice. Screen bipolar history and current psychosis. Assess overdose access, alcohol and substances, pregnancy or breastfeeding, epilepsy, bleeding, liver and renal function, cardiac disease, glaucoma, urinary symptoms and falls according to the drug. Reconcile prescribed, over-the-counter, herbal and recreational substances.
Discuss priorities explicitly. SSRIs commonly offer an acceptable balance, but sexual dysfunction, gastrointestinal effects, sleep disturbance, hyponatraemia and bleeding may matter greatly. Mirtazapine can cause sedation and weight gain, potentially helpful or unacceptable depending on the person. Venlafaxine requires blood-pressure and withdrawal consideration. Tricyclics have anticholinergic, cardiac and overdose toxicity. Monoamine oxidase inhibitors and complex combinations require specialist use. St John's wort has variable preparations and important interactions and is not a simple safe alternative.
Prescribe one clear regimen and explain expected course. Early adverse effects can occur before mood improvement. Provide written instructions, missed-dose advice and warning signs. Avoid giving a large quantity when overdose risk is active; coordinate limited dispensing without using medication access as punishment. For citalopram or escitalopram, apply MHRA dose restrictions, review other QT-prolonging medicines and correct electrolyte risk. Obtain ECG when cardiac history, symptoms, overdose or interactions make it relevant.
Early monitoring is a clinical intervention. Review response and adverse effects within two weeks of starting, with one-week review for people aged 18 to 25 or when suicide risk is a particular concern. Ask specifically about new suicidal thoughts, agitation, akathisia, reduced sleep need and impulsivity. Assess sleep, appetite, sexual effects, adherence and function. Involve a chosen supporter when the person agrees and provide an urgent contact route. Do not increase automatically because improvement is not complete during the first days.
Continue long enough to judge benefit and prevent early relapse. If there is no response by about four weeks at a therapeutic dose with adherence, reassess diagnosis and treatment. After remission, continue at least six months unless contraindicated and review recurrent-risk factors. When stopping, reduce in stages, often with smaller proportional reductions at lower doses. Distinguish withdrawal, which may begin soon after reduction and include sensory or disequilibrium symptoms, from depressive relapse, which generally follows the person's prior syndrome.
Key points
- Before prescribing, confirm indication and severity, previous response, bipolar history, suicide and overdose risk, pregnancy, physical illness, substances and all interacting medicines.
- SSRIs are commonly considered because of tolerability and relative overdose safety, but choose within and beyond the class according to the person's priorities.
- Discuss nausea, sleep and sexual effects, bleeding, hyponatraemia, activation, emotional blunting, driving impairment, discontinuation symptoms and expected onset.
- Sertraline adult depression treatment starts at 50 mg once daily and can increase by 50 mg no more frequently than weekly to 200 mg daily when indicated.
- Citalopram adult depression usually starts at 20 mg once daily; the maximum is 40 mg daily, reduced to 20 mg in older adults and hepatic impairment because of QT risk.
- Mirtazapine is taken once daily at night, commonly starting 15 to 30 mg and adjusted within 15 to 45 mg daily, with sedation and weight gain discussed.
- Review within two weeks, or within one week for age 18 to 25 or particular suicide concern, and repeat as frequently as clinical need requires.
- Assess adherence, early harms, suicidality, mania, akathisia and function before increasing; benefit usually becomes evident within about four weeks when effective.
- Continue effective treatment for at least six months after remission and use staged tapering rather than alternate-day dosing or abrupt cessation when stopping.
02Indications, selection and cautionsWho may benefit, who needs urgent treatment and important alternatives.
The person's comorbidity, interactions, adverse-effect priorities and overdose risk favour a selective serotonin reuptake inhibitor after informed discussion.
New restlessness, reduced sleep need, increased speech, confidence, activity or risk-taking after initiation requires urgent review and bipolar assessment.
Subjective inner restlessness with observable inability to stay still differs from ordinary anxiety and can sharply worsen distress.
Headache, confusion, seizure, weakness or falls after treatment, especially with older age or diuretic use, warrants urgent sodium assessment.
Dizziness, electric-shock sensations, flu-like symptoms, anxiety or vivid dreams soon after reduction suggests withdrawal and needs slower individual tapering.
03Assessment before treatmentTests and checks that guide safe selection.
Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.
- 01
Pre-prescribing clinical reviewFirst step - Why
- Confirm diagnosis, bipolarity, risk, prior treatment, comorbidity, pregnancy, substances and patient priorities.
- Interpretation and limitations
- Selection should explain why anticipated benefit and adverse-effect profile fit this person and why alternatives were not preferred.
- 02
Medicines and interaction reconciliation - Why
- Identify serotonergic, QT-prolonging, bleeding, sedating, enzyme-altering and dependence-forming combinations.
- Interpretation and limitations
- Include OTC and herbal products. Use current interaction and product information rather than assuming all antidepressants share the same profile.
- 03
Physical baseline testing - Why
- Obtain blood pressure, sodium, ECG, liver, renal or other measures when the medicine and comorbidity indicate them.
- Interpretation and limitations
- Testing is targeted, not universal. Cardiac symptoms, electrolyte risk and citalopram interactions lower the ECG threshold.
- 04
One-week or two-week safety review - Why
- Detect suicidal change, activation, akathisia, adverse effects, non-adherence and practical barriers early.
- Interpretation and limitations
- Use one-week review for age 18 to 25 or particular suicide concern; increase contact when risk or harms change rather than waiting for routine benefit review.
- 05
Four-week response review - Why
- Assess whether symptoms and function are improving after an adequate therapeutic trial.
- Interpretation and limitations
- No response prompts diagnosis, adherence, dose, duration and comorbidity review; partial response may justify optimisation when benefit exceeds harm.
04Treatment approachPreparation, options, escalation and aftercare.
01SelectionMatch medicine to person and riskFirst stepPreferredAntidepressant treatment is an informed preferred option.+
- 1Review bipolarity, suicide and overdose risk, previous treatment, pregnancy, physical illness, substances and interactions.
- 2Compare likely benefit, common and serious harms, withdrawal, dosing and monitoring with the person's priorities.
- 3Choose a single clear regimen, provide written safety advice and arrange limited supply or support when overdose access is relevant.
02Early monitoringReview harm before automatic titrationAn antidepressant has been started or its dose increased.+
- 1Arrange one-week review for age 18 to 25 or particular suicide risk and otherwise usually review within two weeks.
- 2Assess suicidal change, mania, akathisia, adherence, sleep, adverse effects, interactions and functional trajectory.
- 3EscalationContinue, adjust, switch or stop safely according to benefit and harm, with urgent care for severe reaction or escalating risk.
03StoppingTaper and distinguish withdrawalThe person chooses to stop after review or adverse effects require planned discontinuation.+
- 1Explain withdrawal and relapse, agree staged dose reductions and use smaller proportional steps as the dose becomes low.
- 2Monitor timing, physical and psychological symptoms and function after each reduction and pause or reverse a step if intolerable.
- 3Resume a slower taper once stable and retain relapse prevention and urgent-contact plans throughout withdrawal.
05Regimens, contraindications and interactionsTreatment details and the circumstances that modify them.
Sertraline
Start 50 mg orally once daily for adult depression; increase by 50 mg steps at intervals of at least one week when needed, to no more than 200 mg daily.Avoid with MAOIs and review serotonergic combinations; monitor activation, bleeding, sodium, sexual dysfunction and hepatic factors, and consider pregnancy and breastfeeding guidance individually.
Citalopram
Start 20 mg orally once daily in adults; maximum 40 mg daily, but use no more than 20 mg daily in adults over 65 or with hepatic impairment.Dose-dependent QT prolongation requires review of cardiac disease, bradycardia, electrolytes and QT-prolonging medicines; avoid with known QT prolongation and follow current MHRA contraindications.
Mirtazapine
Start 15 to 30 mg orally at night and adjust according to response and tolerability within the licensed range of 15 to 45 mg once daily.Warn about drowsiness, weight gain, appetite increase and driving impairment; investigate fever or sore throat for rare blood dyscrasia and review hepatic or renal impairment.
06Complications, monitoring and follow-upAdverse effects, response and longer-term review.
- Review at one week for people aged 18 to 25 or particular suicide concern and usually within two weeks for other adults after initiation.
- Ask explicitly about suicidal thoughts, agitation, akathisia, reduced sleep need, impulsivity and access to overdose quantities at each early contact.
- Monitor weight, sodium, blood pressure, ECG, bleeding or other measures according to age, medicine, symptoms and comorbidity.
- Assess symptom and functional response around four weeks and verify dose, duration and adherence before declaring non-response.
- Continue at least six months after remission, review relapse risk periodically and taper in stages with monitoring when stopping.
07Special situationsVariants, exceptions and circumstances that change the usual approach.
Class choice is not enough
Sertraline and citalopram are both SSRIs but differ in interactions, cardiac restrictions and individual previous response, so selection remains medicine specific.
Akathisia can hide
Patients may describe unbearable anxiety without naming motor restlessness; ask what the body feels compelled to do and observe movement.
Quantity is treatment design
Short prescriptions or supervised dispensing can reduce overdose opportunity while preserving access to effective medication and dignity.
Early effect is not final
Transient nausea or sleep change may settle, but severe activation, mania, suicidality or serotonin toxicity requires immediate reassessment.
Withdrawal can mimic relapse
Rapid onset after dose reduction and prominent sensory or disequilibrium symptoms support withdrawal, although both processes can coexist.
08Common pitfallsFrequent interpretation and management errors.
- 01
Selecting an antidepressant without screening previous mania, overdose risk and interactions.
- 02
Prescribing citalopram above current age or hepatic limits or ignoring QT combinations.
- 03
Calling akathisia anxiety and increasing the medicine without assessment.
- 04
Waiting several weeks to review a young adult with suicide concerns after initiation.
- 05
Assuming no benefit after a few days means a therapeutic trial has failed.
- 06
Supplying large quantities despite an active overdose scenario without a safety plan.
- 07
Stopping abruptly or using alternate-day dosing for short half-life medicines without a taper plan.