Monotherapy

Monotherapy is a treatment approach in which a patient receives a single therapeutic agent or modality to treat a disease, rather than a combination of multiple drugs or therapies. The term is used across medical specialties to describe both pharmacologic regimens and non-drug treatments that stand alone. In practice, monotherapy is often chosen when a single agent is expected to provide adequate control with a favorable safety profile.

In pharmacology, monotherapy typically refers to prescribing one medication at a time, with escalation to additional agents only if necessary. In infectious diseases, antibiotic monotherapy uses one antimicrobial agent; in oncology, a single cytotoxic or targeted agent may be used for tumors that respond to it. In psychiatry and neurology, monoaminergic agents or other single-agent regimens may be used as initial therapy. Cardiovascular and metabolic diseases also employ drug monotherapy as initial management.

Advantages include simpler regimens, reduced risk of drug–drug interactions, improved adherence, and often lower cost. Fewer adverse events may occur when only one drug is used. Monotherapy can be preferred when a disease is mild, confidently controlled by one agent, or when guideline recommendations favor a stepwise approach beginning with a single drug.

Limitations include insufficient control of disease activity in many chronic or multifactorial conditions, development of tolerance or resistance in infections, and delayed attainment of therapeutic targets. If response is inadequate or side effects arise, clinicians may escalate to combination therapy or add second-line agents, guided by evidence-based guidelines and patient preferences.

The choice between monotherapy and combination therapy depends on disease stage, patient comorbidities, and risk–benefit considerations. Ongoing assessment of efficacy, safety, adherence, and quality of life informs adjustments.