Concise answers when you need the essentials, with deeper clinical context and transparent source links when the decision needs more scrutiny.
Search by active ingredient or familiar medicine name.
Sodium phenylbutyrate is an ammonia-scavenging treatment for certain inherited urea cycle disorders. It helps remove waste nitrogen through the urine and is used alongside an individually managed protein-restricted diet under specialist supervision.
Sodium picosulfate monohydrate is a stimulant laxative activated by bacteria in the colon. The selected oral solutions are licensed to relieve occasional constipation.
Sodium polystyrene sulfonate is an ion-exchange resin used to lower high blood potassium. Its licensed role includes hyperkalaemia associated with very low or absent urine output and hyperkalaemia in people requiring dialysis.
Sodium selenite supplies selenium, an essential trace element needed by antioxidant enzymes and thyroid-hormone metabolism. This intravenous product is used to prevent deficiency during parenteral nutrition or to treat proven deficiency that nutrition alone cannot correct.
Sodium selenite pentahydrate is a mineral supplement that provides selenium, an essential trace element. Selected oral and injectable products are licensed for proven selenium deficiency that cannot be corrected through food.
Sodium tetradecyl sulfate is a detergent sclerosant injected into unwanted superficial leg veins. It is used to close varicose, reticular and spider veins so that the treated vein is gradually replaced by fibrous tissue.
Sodium thiosulfate is an intravenous antidote used in hospital. Selected products are licensed to help prevent cisplatin-related hearing damage in certain children and young people, or with another antidote to treat life-threatening cyanide poisoning.
Sodium valproate is an anticonvulsant that reduces excessive electrical activity in the brain. Selected products are licensed for epilepsy; some prolonged-release products are also licensed for manic episodes in bipolar disorder when other treatments are unsuitable.
A prolonged-release form of valproate used for epilepsy, subject to strict reproductive-safety restrictions.
Sodium zirconium cyclosilicate is a non-absorbed oral potassium binder used to treat high blood potassium in adults. It captures potassium in the gut so that more leaves the body in stools, helping lower and control blood potassium.
Sofosbuvir is a direct-acting antiviral used to treat chronic hepatitis C. It is prescribed by a specialist as part of combination treatment, not on its own.
Sofosbuvir + velpatasvir combines two direct-acting antivirals that block different steps in hepatitis C virus replication. It is used under specialist supervision for chronic hepatitis C infection in adults and children aged 3 years and older.
This fixed combination contains three direct-acting antivirals that block hepatitis C virus at different stages of replication. It is licensed for eligible adolescents and adults with chronic hepatitis C and is started and monitored by clinicians experienced in hepatitis C care.
Solifenacin + tamsulosin combines an antimuscarinic with an alpha-blocker. It is licensed for men with moderate to severe bladder-storage and urine-flow symptoms associated with benign prostate enlargement when treatment with one medicine has not controlled symptoms adequately.
Solriamfetol hydrochloride is a wake-promoting treatment for adults with excessive daytime sleepiness caused by narcolepsy or obstructive sleep apnoea. In obstructive sleep apnoea, it supplements rather than replaces treatment for the underlying airway obstruction.
Somapacitan is a long-acting form of recombinant human growth hormone. It replaces growth hormone in adults with growth hormone deficiency and supports growth in children and adolescents whose growth failure is caused by this deficiency.
Somatrogon is a long-acting recombinant growth hormone treatment for children and adolescents aged 3 years and over whose growth is affected by insufficient growth hormone secretion.
Somatropin is a laboratory-made version of human growth hormone. Specialists use it to replace deficient growth hormone and to support growth or body composition in certain licensed childhood conditions.
Sorafenib tosilate is an oral targeted cancer treatment that blocks several protein kinases involved in tumour growth and blood-vessel formation. In the UK, the selected product is licensed for certain liver, kidney and differentiated thyroid cancers under specialist supervision.
Sotalol hydrochloride is a beta blocker with an additional action on the heart's electrical recovery phase. It is used to treat or prevent selected serious ventricular and supraventricular heart rhythm disorders.
Sotorasib is a targeted anticancer treatment that blocks abnormal KRAS G12C signalling. In the UK, it is licensed for certain adults with previously treated, locally advanced or metastatic non-small cell lung cancer confirmed to carry this mutation.
Soya oil is used in an emollient bath additive for dry skin associated with conditions such as dermatitis and eczema. It disperses through bath water and leaves an oily film that helps reduce moisture loss.
Spesolimab is a targeted monoclonal antibody that reduces inflammation by blocking the interleukin-36 receptor. It is used alone under specialist supervision to treat generalised pustular psoriasis flares in adults and adolescents aged 12 years and over.
Spironolactone is a potassium-sparing diuretic and aldosterone blocker. It is mainly used for heart failure or fluid build-up; selected products are also licensed for primary aldosteronism and high blood pressure.
St John’s wort is a herbal product made from Hypericum perforatum. Selected products are traditionally used to relieve slightly low mood and mild anxiety; this is based on traditional use rather than clinical evidence of effectiveness.
This is allergen immunotherapy containing standardised extracts from two common house dust mite species. It is used to reduce immune sensitivity in selected people whose house dust mite respiratory allergy remains troublesome despite symptom-relieving treatment.
This is allergen immunotherapy containing a standardised extract of white birch pollen. It is used for confirmed moderate-to-severe allergic nose and/or eye symptoms caused by the birch-related tree pollen group when symptom-relieving treatments have not provided adequate control.
Stiripentol is an antiseizure medicine used for Dravet syndrome. In the UK, it is licensed alongside clobazam and valproate when generalised tonic-clonic seizures remain inadequately controlled.
Streptozocin is a cytotoxic nitrosourea chemotherapy that damages cancer-cell DNA. It is licensed with fluorouracil for certain progressive or symptomatic pancreatic neuroendocrine tumours that cannot be removed surgically or have spread.
Sufentanil citrate is a potent opioid painkiller. The selected UK product is used for acute moderate to severe pain in adults and is placed under the tongue by a healthcare professional in a medically monitored setting.
Sugammadex sodium is used by anaesthetists to reverse certain muscle-relaxing agents used during anaesthesia, helping muscle function and breathing recover.
Sulfadiazine is an oral sulfonamide antibiotic that stops susceptible organisms multiplying. Its use is limited and often specialist-led; it includes susceptible infections and non-licensed combination treatment of toxoplasmosis.
This combination antibiotic, also called co-trimoxazole, is used for selected susceptible infections. It also has roles in treating or preventing Pneumocystis jirovecii pneumonia and toxoplasmosis, and in treating nocardiosis.
Sulfasalazine is an anti-inflammatory aminosalicylate and disease-modifying antirheumatic treatment. Selected products are licensed for inflammatory bowel disease; gastro-resistant tablets are also licensed for rheumatoid arthritis.
Sulfur hexafluoride is an ultrasound contrast agent containing tiny gas-filled bubbles. It improves ultrasound signals so clinicians can see the heart, blood vessels, tissue blood flow or urinary tract more clearly when an unenhanced scan is inconclusive.
Sulpiride is a substituted benzamide antipsychotic licensed in the selected products for acute and chronic schizophrenia. It works by blocking dopamine signalling in the brain.
Sumatriptan is a triptan used to treat a migraine attack after it has started; it does not prevent attacks. The selected nasal spray is licensed for acute migraine with or without aura.
Sumatriptan succinate supplies sumatriptan, a triptan that treats an attack after it has started rather than preventing future attacks. Selected tablets are licensed for migraine, while selected subcutaneous injections are licensed for migraine and cluster headache.
Sunitinib is an oral targeted anticancer treatment called a protein kinase inhibitor. It is licensed for certain gastrointestinal stromal tumours, advanced or metastatic renal cell carcinoma, and progressive pancreatic neuroendocrine tumours in adults.
Sunitinib malate is an oral protein kinase inhibitor used by specialist cancer teams for certain advanced kidney cancers, gastrointestinal stromal tumours and pancreatic neuroendocrine tumours.
Suxamethonium chloride is a short-acting depolarising neuromuscular blocker used to relax skeletal muscles during general anaesthesia. It causes paralysis, including of the breathing muscles, but does not cause unconsciousness or relieve pain.