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.
Selinexor is an oral targeted anticancer treatment for adults with previously treated multiple myeloma. It is licensed for use with other myeloma treatments rather than alone.
Selpercatinib is an oral targeted anticancer treatment that blocks abnormal RET signalling. It is used for certain advanced lung and thyroid cancers when testing confirms a relevant RET gene alteration.
Selumetinib is an oral selective MEK inhibitor for symptomatic plexiform neurofibromas associated with neurofibromatosis type 1 when complete surgical removal is not possible. The granule formulation is licensed for children aged 1 to under 7 years and older people with swallowing difficulties.
Selumetinib hydrogen sulfate is a targeted MEK inhibitor used for symptomatic plexiform neurofibromas that cannot be operated on in people with neurofibromatosis type 1. The selected UK product is licensed for adults and children aged 3 years and older and is prescribed through specialist care.
Semaglutide is a GLP-1 receptor agonist available as injections and tablets. Depending on the product, it is licensed for type 2 diabetes, weight management and selected obesity-related cardiovascular or liver disease.
Senna fruit extract with Tinnevelly senna pods is a plant-derived stimulant laxative licensed for short-term relief of occasional constipation. It works mainly in the large bowel.
Sennoside is a stimulant laxative derived from senna fruit, used for short-term relief of occasional constipation when dietary fibre, fluids and activity have not been sufficient.
Setmelanotide is a prescription injection that activates the brain’s melanocortin-4 receptor pathway. It is used under specialist supervision for hunger and obesity caused by certain rare genetic conditions or acquired hypothalamic injury; it is not a general weight-loss treatment.
Sevelamer hydrochloride is a non-absorbed, calcium-free phosphate binder. It is used alongside dietary and other renal care to control high blood phosphate in adults receiving haemodialysis or peritoneal dialysis.
Sevoflurane is a volatile general anaesthetic inhaled as vapour. An anaesthetist uses it to start or maintain unconsciousness during surgery in adults and children.
Siltuximab is a monoclonal antibody that blocks interleukin‑6, an inflammatory signalling protein. It is used under specialist supervision for eligible adults with multicentric Castleman disease who are HIV-negative and HHV‑8-negative.
Simeticone is an antiflatulent that acts locally in the gut. It is used for relief of trapped wind, bloating, abdominal distension and discomfort associated with intestinal gas, although evidence of benefit is limited.
Simoctocog alfa is a recombinant human clotting factor VIII that replaces deficient factor VIII in haemophilia A to treat bleeding and help prevent bleeds in adults and children.
Simvastatin is a statin that lowers cholesterol and other blood fats. It is used with diet and other measures to treat high cholesterol and reduce cardiovascular risk in people with established atherosclerotic disease or diabetes.
Siponimod fumaric acid is an oral sphingosine-1-phosphate receptor modulator. It is used under specialist supervision for adults with secondary progressive multiple sclerosis that remains active through relapses or inflammatory MRI findings.
Sirolimus is an immunosuppressant that blocks the mTOR pathway. It is mainly used to help prevent rejection after kidney transplantation and to treat sporadic lymphangioleiomyomatosis, a rare lung disease.
Sodium acid phosphate is an inorganic phosphate salt supplied as an effervescent tablet. It is licensed for selected causes of high blood calcium and for low phosphate associated with vitamin D-resistant bone disorders. Its role is to supply phosphate or reduce calcium absorption from the gut.
A rectal laxative supplied as a disposable micro-enema. It helps soften retained stool and empty the lower bowel, and is also used before certain bowel examinations.
Sodium chloride is salt supplied in medicinal forms to replace sodium and chloride, restore fluid balance, or carry compatible injected medicines. Some products are sterile solutions for washing the eye or irrigating tissues.
Sodium chloride with succinylated gelatin is an intravenous colloid solution that temporarily replaces fluid lost from the circulation. It is used in hospital when circulating blood volume needs support and crystalloid fluids alone are insufficient.
Sodium citrate is an alkalising antacid used before general anaesthesia for caesarean birth to make stomach contents less acidic if regurgitation and aspiration occur.
Sodium feredetate trihydrate is an oral iron preparation in which iron is bound in a chelate. It is used to replace iron in iron deficiency anaemia, including in children and in pregnancy when other oral iron preparations are not well tolerated.
Sodium fluoride is a mineral treatment used on teeth to prevent and treat dental caries. This prescription toothpaste is intended for people aged 10 years or over who need greater protection from decay affecting tooth crowns or exposed roots.
Sodium fusidate is the sodium salt of fusidic acid, a narrow-spectrum antibiotic with particular activity against staphylococci. In the selected products, an ointment treats susceptible bacterial skin infections, while tablets treat susceptible staphylococcal infections affecting the skin, wounds, bone, lungs, blood, heart tissue or cystic fibrosis.
An antacid and antiflatulent oral solution for babies, licensed to relieve distress associated with trapped wind in infants. Evidence that gripe water improves infant colic is limited.
Sodium iodide I 123 is a diagnostic radiopharmaceutical taken up by the thyroid gland. Its gamma radiation allows assessment of thyroid function, appearance and iodine uptake; it is not a treatment.
A rinse-off shampoo containing two cleansing surfactants. The selected product is licensed to treat infant cradle cap and care for infant scalp and hair.
Sodium nitrite is an emergency antidote used in hospital for acute cyanide poisoning judged to be life-threatening. It is used with sodium thiosulfate alongside oxygen, supportive care and appropriate decontamination.
Sodium nitrite plus sodium thiosulfate is a two-part antidote used in hospital for acute cyanide poisoning judged to be life-threatening. It is used alongside urgent decontamination, oxygen and other supportive care.
Sodium nitroprusside dihydrate is a potent intravenous vasodilator that relaxes arteries and veins. In adults, it is used in closely monitored hospital settings for hypertensive crises or controlled blood-pressure reduction during surgery.
Sodium oxybate is a central nervous system depressant used at night for narcolepsy with cataplexy. It can reduce sudden muscle weakness, improve disrupted night-time sleep and lessen excessive daytime sleepiness, but does not cure narcolepsy.
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.