Drug classes
Drug classes: how a family of medicines works, what it targets in the body, which conditions it treats and which medications on this site belong to it. Educational, not prescribing advice.
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Showing all 57 drug classes
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5-alpha reductase inhibitors
A group of medicines that stop testosterone turning into the hormone DHT; finasteride, described by the NHS for an enlarged prostate and male pattern hair…
5-HT3 receptor antagonists
Anti-sickness medicines that block 5-HT3 receptors; ondansetron is the member covered on this site. Ondansetron is used to prevent nausea and vomiting after…
A
ACE inhibitors
Medicines ending in -pril that block the enzyme which makes angiotensin II, lowering blood pressure, unloading a failing heart and protecting the kidneys in…
Alpha blockers
Alpha blockers, also called alpha-adrenoreceptor antagonists, are medicines that relax muscle; tamsulosin is used to relax the muscle around the bladder and…
Androgens
Steroid hormones that act on the androgen receptor. Testosterone in its various forms replaces the testes' output in hypogonadism and masculinises the body in…
Angiotensin receptor blockers
Medicines ending in -sartan that block the receptor angiotensin II acts on. They do the same job as ACE inhibitors without the cough, and are the usual…
Anticoagulants
Medicines that slow the clotting cascade to prevent and treat clots in veins and the heart: strokes in atrial fibrillation, deep vein thrombosis and pulmonary…
Antihistamines
Medicines that block histamine's H1 receptors to relieve hay fever, hives and itching. Newer members (cetirizine, loratadine, fexofenadine) cause little…
Antimalarial DMARDs
MedlinePlus places hydroxychloroquine in a group of medicines called antimalarials and also describes it as an antirheumatic drug. The NHS describes it as a…
Antimetabolite DMARDs
Antimetabolite DMARDs are a group of disease-modifying medicines; methotrexate is the member covered on this site. Methotrexate is an immunosuppressant used…
Antimotility agents
Antimotility agents are medicines that slow the bowel to treat diarrhoea, and loperamide is the member covered on this site. Product information for UK…
Antiplatelet drugs
Medicines that stop platelets clumping into the clots that block arteries. The backbone of treatment after heart attacks, strokes and stents.
Azole antifungals
Antifungal medicines, including fluconazole, used for thrush and other fungal infections.
B
Benzodiazepines
Benzodiazepines are depressant medicines that slow the central nervous system, and diazepam is the member covered on this site. The MHRA says dependence can…
Beta blockers
Medicines ending in -olol that shield the heart from adrenaline, slowing it and reducing its oxygen demand. Core treatment for angina, after heart attacks, in…
Biguanides
Metformin is the only biguanide in routine use and the first-line tablet for type 2 diabetes: it lowers glucose without causing hypoglycaemia or weight gain.
Bisphosphonates
Medicines that slow bone loss by disabling the cells that dissolve bone, cutting hip and spine fractures in osteoporosis and treating Paget's disease and…
Bronchodilators
Inhaled medicines that relax the muscle around the airways within minutes (salbutamol, terbutaline) or for about 12 hours (salmeterol, formoterol) to 24 hours…
C
Calcium channel blockers
Medicines that relax the muscle in artery walls (and, for some members, slow the heart) by blocking the calcium channels those muscles need to contract. Used…
Cholesterol absorption inhibitors
Cholesterol absorption inhibitors are medicines that lower cholesterol by partly blocking its absorption in the small intestine. They are used on their own…
Combined hormonal contraceptives
Combined hormonal contraceptives contain both an oestrogen and a progestogen, and include the combined pill, a skin patch and a vaginal ring.
Contrast agents
Substances given to make blood vessels, organs, the gut or joints stand out on imaging: iodinated agents for X-ray and CT, gadolinium agents for MRI,…
Corticosteroids
Synthetic versions of cortisol that switch off inflammation of any cause: inhaled for asthma, as tablets or injections for flares of many diseases, and as…
D
Diagnostic radiopharmaceuticals
Radioactive medicines given in tiny amounts so that a gamma camera or PET scanner can show where they accumulate: bone turnover, blood flow to the heart,…
Dopamine antagonist anti-sickness medicines
Dopamine antagonist anti-sickness medicines are used to treat nausea and vomiting, and metoclopramide is the member covered on this site. The MHRA has…
G
Gabapentinoids
Gabapentinoids are the group that contains pregabalin and gabapentin, which are used for epilepsy and nerve pain.
GLP-1 receptor agonists
GLP-1 receptor agonists are medicines that imitate GLP-1, a hormone the body releases after eating. Semaglutide (Ozempic, Wegovy, Rybelsus) is one; tirzepatide…
I
Influenza vaccines
Seasonal vaccines against influenza A and B, reformulated every year: inactivated injected vaccines for most people and a live attenuated nasal spray for…
Insulins
Injected replacements for the hormone the pancreas no longer makes or cannot make enough of: essential in type 1 diabetes and used in type 2 diabetes when…
L
Leukotriene receptor antagonists
Montelukast is a prescription medicine that helps prevent asthma symptoms. Asthma and Lung UK describes it as an add-on taken alongside the regular preventer…
Loop diuretics
Powerful diuretics that make the kidneys excrete salt and water within an hour. Used to clear fluid in heart failure, kidney and liver disease. Furosemide,…
M
Macrolides
Antibiotics that stop bacteria making proteins by binding the bacterial ribosome, used for chest, ear, skin and sexually transmitted infections and as the main…
Mineralocorticoid receptor antagonists
Mineralocorticoid receptor antagonists, also called aldosterone antagonists, are medicines that act against the hormone aldosterone. Spironolactone and…
N
NaSSA antidepressants
The NHS groups antidepressants into types such as SSRIs, SNRIs, tricyclics and MAOIs, and lists mirtazapine as a noradrenaline and specific serotonergic…
Nitrates
Vasodilators that relieve angina within minutes by relaxing veins and coronary arteries. Available as a spray for attacks and as long-acting tablets for…
Nitroimidazoles
Antibiotic and antiparasitic medicines, including metronidazole and tinidazole, that act on bacteria and parasites. The NHS says metronidazole is an antibiotic…
Non-opioid analgesics
First-line painkillers without opioid or anti-inflammatory action: paracetamol (acetaminophen) above all, safe at normal doses for most people and most types…
NSAIDs
Painkillers that also reduce inflammation and fever: ibuprofen, naproxen, diclofenac and the COX-2 selective coxibs. Excellent for short-term musculoskeletal…
Nucleoside antivirals
Antiviral medicines used for herpes virus infections such as cold sores, shingles, chickenpox and genital herpes. Aciclovir is described on this site, and…
O
Oestrogens
Steroid hormones that act on the oestrogen receptor. Estradiol and related oestrogens replace the ovaries' output after the menopause, treat genitourinary…
Opioids
Strong painkillers that act on the body's own endorphin receptors: morphine, codeine, tramadol, oxycodone, fentanyl. Essential for severe acute pain and cancer…
Osmotic laxatives
Osmotic laxatives draw water into the bowel to soften poo; lactulose is the one covered on this site. The NHS says osmotic laxatives such as lactulose and…
P
PDE5 inhibitors
PDE5 inhibitors are medicines that include sildenafil and tadalafil, used mainly for erection problems. Some are also used for pulmonary hypertension. The NHS…
Penicillins
The oldest family of antibiotics and still the first choice for many chest, ear, throat, skin and dental infections: amoxicillin, co-amoxiclav, flucloxacillin…
Proton pump inhibitors
The strongest acid-reducing medicines (omeprazole, lansoprazole, pantoprazole, esomeprazole), which heal ulcers and reflux by shutting down the acid pumps in…
S
SGLT2 inhibitors
SGLT2 inhibitors are tablets used for type 2 diabetes, heart failure and chronic kidney disease. They lower blood sugar by acting on the kidneys, as the NHS…
SNRIs
SNRIs are a group of antidepressants whose NHS examples are duloxetine and venlafaxine. They act on both serotonin and noradrenaline. The NHS says venlafaxine…
SSRIs
The most widely used antidepressants (sertraline, citalopram, escitalopram, fluoxetine, paroxetine), also first-line for anxiety disorders, panic, OCD and…
Statins
The main cholesterol-lowering medicines. They cut LDL cholesterol by 30-55% and reduce heart attacks and strokes in anyone at raised cardiovascular risk.
Sulfonylureas
Sulfonylureas are tablets for type 2 diabetes that prompt the pancreas to make more insulin. Low blood sugar (a hypo) is one of their most common side effects,…
T
Tetracyclines
Tetracyclines are a group of antibiotics that stop bacteria from making the proteins they need to survive. Doxycycline is the member described here, and the…
Thyroid hormones
Synthetic thyroxine (levothyroxine) replaces what an underactive thyroid cannot make, restoring metabolic rate; the dose is tuned by the TSH blood test.…
Tricyclic antidepressants
Tricyclic antidepressants are a group of medicines that includes amitriptyline, nortriptyline, imipramine and clomipramine. They are used to treat depression,…
Triptans
Triptans are medicines for treating migraine attacks, and sumatriptan is the triptan covered on this site. The NHS says sumatriptan relieves symptoms of…