In certain cases, for example, a septic patient, you must ensure that the first dose of the appropriate antibiotic(s) is given WITHIN ONE HOUR. It is not enough to write it up. Check availability of that drug on that ward, and check nurses understand urgency of delivering drug to patient. This is especially true for these conditions: suspected bacterial meningitis, septic arthritis, neutropenic sepsis, severe sepsis (of any cause), and also HSV encephalitis.

• Penicillin allergy: penicillins are life-saving antimicrobials and patients should not be labelled ‘penicillin-allergic’ without careful consideration. Nausea, vomiting or diarrhoea do not, by themselves, constitute an allergic reaction. They are not a contraindication for penicillin use. Anaphylaxis related to histamine release occurs about 30–60 min after administration of a penicillin; symptoms may include erythema or pruritus, angioedema, ↓BP or shock, urticaria, wheezing, rhinitis. Patients with a history of immediate hypersensitivity/anaphylaxis to penicillin should NOT receive a cephalosporin. TAKING A RELIABLE HISTORY IS VERY IMPORTANT.
  
• ERTAPENEM or MEROPENEM is recommended as an alternative to penicillin for some severe infections. However, if there is a history of an anaphylactic reaction, or an accelerated allergic reaction DO NOT prescribe these drugs. Please discuss alternative antibiotics with a microbiologist. Remember, penicillins (and cephalosporins) can also be nephrotoxic (as they can induce an interstitial nephritis).
  
• Definite Penicillin allergy – the following must not be given: Amoxicillin, Augmentin (Co-amoxiclav), Benzylpenicillin (Penicillin G), Flucloxacillin, Phenoxymethylpenicillin (Penicillin V), Piperacillin/tazobactam (Tazocin), Pivmecillinam, Temocillin.
  
• WARNING: this is a quick look-up guide for drugs with which you should be familiar and in no way replaces the BNF. All drugs should be checked in the BNF for safety of use in pregnancy, breastfeeding and renal and liver failure. Allergy is such an obvious contraindication that it is not mentioned. All allergies should be documented.

ABCIXIMAB (REOPRO) (monoclonal Ab antiplatelet activity). ACS/PCI: ABCIXIMAB* 250 mcg/kg IV bolus over 1 min 10–60 min before the start of PCI, followed by a continuous IV infusion of ABCIXIMAB* 125 ng/kg/min (max 10 mcg/min) for 12 h. SE: bleed, low platelets, N, V, H, F, alveolar haem, ARDS, low BP. Caution: risk of bleeding complications or imminent surgery, e.g. CABG. Specialist use only – prescribe under senior cardiology direction. *Note: caution as units here are microgram and nanograms.

(N) ACETYL CYSTEINE (PARVOLEX or NAC) (replenishes glutathione). Paracetamol toxicity: N-ACETYL CYSTEINE = NAC G5 = 5% GLUCOSE. Bag 1: NAC 150 mg/kg in 200 ml G5 IV over 1 h. Bag 2: NAC 50 mg/kg in 500 ml G5 IV over 4 h. Bag 3: NAC 100 mg/kg in 1 L G5 over 16 h. Total NAC dose given is 300 mg/kg in 21 h. NB. First bag now over 1 h to reduce risk of reactions. SE: low K, anaphylactoid reaction (N, V, R, flushing, urticaria, itching, wheeze) more common if given too quickly. Slow and continue if possible with CHLORPHENAMINE 10 mg IV/IM. Use plasma levels and treatment line to judge therapy. Do not stop treatment due to SE without senior discussion. May continue NAC at dose rate of 3rd bag if any liver damage (INR >2) or AST >1000 until normalise. Take hepatology advice.

ACICLOVIR (inhibits DNA polymerase in infected cells only). HSV/VZV infections (not CMV/EBV). Non-genital/genital: ACICLOVIR 200–400 mg 5/d PO for 5 d. (10 d if genital). Higher dose/longer course in HIV and immunocompromised. Severe infection: ACICLOVIR 10 mg/kg IV 8 h for 5 d or more. HSV encephalitis: ACICLOVIR 10 mg/kg IV 8 h × 21 d until CSF PCR negative. Age >16 with chickenpox or shingles: ACICLOVIR 800 mg PO 5/d for 7 d given as early as possible. SE: N, V, R, H, abdo pain, confusion (IV), phlebitis. Hepatotoxicity, AKI, SEIZ. Confirm CSF negative for HSV before stopping treatment for HSV encephalitis. Reduced dose in renal failure. Ensure well hydrated to prevent AKI. Give over 1 h in 0.9% NS.

ACTIVATED CHARCOAL (binds with a surface area of 1000 m2/g). Single dose: ACTIVATED CHARCOAL 50–100 g (1 g/kg) PO/NG in 250 ml water PO/NG given if within 1 h of toxin ingestion (2 h with aspirin, opiate, TCA). May need to give IV antiemetic. Multidose activated charcoal (MDAC) for carbamazepine, dapsone, quinine, theophylline ingestion: ACTIVATED CHARCOAL 50 g (1 g/kg) PO/NG in 250 ml water then 12.5 g/h. MDAC interrupts enterohepatic recirculation and is vital. Control N&V with IV ONDANSETRON in order to perform MDAC treatment. SE: black stools, pneumonitis if aspirated, constipation (give with laxative), N&V (give with antiemetic). Other drugs that bind: methotrexate, benzodiazepine, phenobarbital.

ADENOSINE (nucleoside – blocks purine A2 receptors). Terminates re-entrant SVTs, e.g. AVNRT/AVRT/atrial flutter: if on dipyridamole, cardiac transplant or via central line start low with: ADENOSINE 1–3 mg fast IV over 1–3 sec then 20 ml NS bolus (use a 3-way tap). Usual dose ADENOSINE 6 mg fast IV with 20 ml NS bolus – watch ECG; if fails then ADENOSINE 12 mg fast IV with a 20 ml NS bolus (use a 3-way tap) watch ECG. SE: low BP, flushing, breathless, angina, H, palpitations, transient asystole, bronchospasm, SEIZ. Cautions: warn that transient unpleasant symptoms may occur. Aminophylline or theophylline may reduce effect of adenosine. Avoid in asthmatics, heart block, pregnancy. In those with asthma/COPD and narrow complex tachycardia then IV Verapamil may be preferred.

ADRENALINE (EPINEPHRINE) (α and β agonist can cause peripheral vasodilation (a β2 effect) or vasoconstriction (an α effect); as the dose increases α effects dominate). With all inotropes start low and up titrate to response. Adrenaline increases HR and stroke volume and SVR at higher doses. Cardiac arrest: ADRENALINE 1 mg (1 in 10 000) IV/IO given as 10 ml mini-jet every 3–5 min (ALS). Anaphylaxis: ADRENALINE 0.5 ml = 0.5 mg of 1 in 1000 IM. Give into anterolateral aspect of muscle bulk of the middle third of the thigh in adults. May be repeated at 5 min intervals depending on HR/BP. Bradycardia: ADRENALINE 2–10 mcg/min IV. Titrate to response. Closely monitor and titrate dose. Overdose may cause fatal arrhythmias. SE: N, V, overdose can cause fatal arrhythmias, lactic acidosis. Caution: IHD, severe angina, HOCM, stroke, arrhythmias. Telemetry and resus equipment needed. IV usage only for cardiac arrest and in exceptional circumstances in an ITU setting under close observation.

ALBUMIN (human albumin solution (HAS)). Ascites, hepatorenal syndrome, plasma exchange: 500 ml HAS 4.5–5% (20 g albumin), or 100 ml 20% HAS (20 g albumin). Usually issued from blood bank on named patient basis. 20% albumin is hyperoncotic and can expand up to 400 ml within 25 min and so rapid administration can cause overload and CCF so care must be taken.

ALENDRONATE (bisphosphonate). Postmenopausal osteoporosis, Paget’s disease, bone metastasis, breast cancer: ALENDRONATE 10 mg OD or 70 mg once weekly. (Take with glass of water and remain standing or sit up on empty stomach for 30 min before any other intake.) Not on going to bed. SE: N, V, D, H, oesophageal ulceration, stress fractures. Patients need calcium and vitamin D supplement if not replete. Osteonecrosis of the jaw may be seen in cancer patients (get dental assessment first).

ALLOPURINOL (xanthine oxidase inhibitor). Not for acute gout. Gout prevention: (2+ attacks): ALLOPURINOL 100–300 mg OD with food. Reduce dose if renal impairment. Use lowest dose to keep uric acid <6 mg/dL. Tumour lysis syndrome: ALLOPURINOL 100–300 mg 8 h. SE: acute gout, N, V, R, AKI, risk of SJS or TEN (Asian HLA-B*5801 allele), liver toxicity, gynaecomastia. Cautions: ↑INR in those on Warfarin. An NSAID or low dose of Colchicine 0.5 mg 12 h can be given for a month initially along with Allopurinol 100 mg to prevent acute attacks. Severe fatal toxicity with Azathioprine or Ciclosporin.

ALTEPLASE. PE with haemodynamic compromise under expert guidance: ALTEPLASE 10 mg over 2 min then 90 mg over 2 h. Max 1.5 mg/kg for those weighing <65 kg. STEMI (within 12 h of symptoms onset): ALTEPLASE 15 mg IV bolus followed by 0.75 mg/kg (max 50 mg) IV over 30 min and then 0.5 mg/kg (max 35 mg) IV over 60 min. If weight >67 kg give 15 mg/50 mg/35 mg. Ischaemic stroke: ALTEPLASE 0.9 mg/kg (max dose 90 mg) with 10% bolus and 90% over 60 min. Interactions: other antithrombotics ↑bleeding risk. SE: low BP, bleeding; mild ↓BP may need IV fluids and leg raising, bleeding, anaphylaxis, angioneurotic oedema, tongue swelling with alteplase especially if on ACEI. Cautions: anaphylaxis, active bleeding, anticoagulation, varices, aortic dissection, cavitating lung disease, heavy vaginal bleeding, stroke disease (take specialist advice), active peptic ulcer disease, anaemia suggesting occult bleeding, recent surgery, recent trauma, severe hypertension, pericarditis, any haemorrhagic stroke, active bleeding, trauma, malignancy.

AMILORIDE (K-retaining diuretic). CCF: AMILORIDE 2.5–10 mg OD PO. SE: high K, low BP, GI upset, low Na. Watch for lithium toxicity.

AMINOPHYLLINE/THEOPHYLLINE (phosphodiesterase inhibitor). Asthma, COPD, bronchospasm: loading dose: AMINOPHYLLINE 250–500 mg (max 5 mg/kg) then infusion over 20 min in 100 ml NS or G5 (no loading dose if on aminophylline or theophylline already). Maintenance dose: AMINOPHYLLINE 500–750 mg in 500 ml over 24 h (0.5 mg/kg/h), adjust as per levels. Smokers need higher dose; elderly or CCF smaller dose, e.g. long term oral dosing: sustained release THEOPHYLLINE 175–500 mg PO BD. SE: N, V, restlessness, insomnia, serious arrhythmias, convulsions. Cautions: monitor plasma levels. Aim for serum levels of 10–20 mg/L. Wait until 4–6 h after infusion started. Stop infusion and wait 15 min and then take level. Interactions: Ciprofloxacin, Macrolides, oral contraception, Cimetidine can lead to theophylline toxicity. Enzyme inducers reduce levels. Levels increased by cardiac disease, hepatic disease or concurrent administration of hepatic enzyme inhibitors. Decreased by smoking and hepatic enzyme inducers.

AMIODARONE. It is irritant and extravasation can be serious, so use central access where possible. Cardiac arrest: AMIODARONE 300 mg IV/IO with 20 ml flush (G5) preferably via central line or large Venflon and flush. Stable tachycardia/chemical cardioversion: AMIODARONE 300 mg diluted in 250 ml of 5% dextrose and run through a new, proximal cannula, in a large peripheral vein, e.g. antecubital fossa. If initial bolus is unsuccessful then an infusion of 900 mg over the following 23 h may be commenced. This should always be administered through a central cannula, e.g. PICC line, femoral or neck line. This should be diluted in a 500 ml bag of 5% dextrose over 23 h. SE: N, V, low BP, ↓HR, thrombophlebitis, photosensitivity, thyroid dysfunction, alveolitis, TdP. Extravasation causes tissue damage. Follow local treatment policies. Ensure peripheral IV lines are working and flush after usage. Caution: Amiodarone should not be used in individuals with TdP (polymorphic VT) or a long QT because it prolongs QT interval. Will increase INR and may raise Digoxin, Diltiazem and Verapamil levels with ↓HR. Watch levels. See BNF.

AMITRIPTYLINE (TCA; ↑levels of NA,5HT, antimuscarinic effects). Neuropathic pain/migraine prevention: AMITRIPTYLINE 10–75 mg ON, titrate dose up under specialist. For depression (specialist only): AMITRIPTYLINE 30–75 mg ON. SE: toxic in overdose. Always come off antidepressants gradually. Sedation, arrhythmias, ↓BP, confusion, dry mouth, urinary retention, weight gain, neuroleptic malignant syndrome, long QT. Avoid if MAOI use in past 2 weeks. Avoid with glaucoma, epilepsy, phaeochromocytoma or cardiac disease.

AMLODIPINE (dihydropyridine CCB). Vasospasm, angina, HTN: AMLODIPINE 5–10 mg OD PO. SE: low BP, reflex tachycardia, ankle oedema, leg ulcers. Caution: reduce Simvastatin 40 mg to 20 mg ON or use Atorvastatin.

AMOXICILLIN (broad spectrum bactericidal β-lactam). CAP, UTI, listeria: AMOXICILLIN 500 mg to 1 g 8 h PO/IM/IV infusion. Severe, endocarditis: AMOXICILLIN 500 mg 8 h to 2 g 4 h. SE: APX, N, V, D, cholestasis, severe rash if EBV/CMV/leukaemia. Reduce dose in renal failure.

AMPHOTERICIN B. Systemic infection with aspergillosis, candidiasis, coccidiomycosis, cryptococcus, histoplasmosis, visceral leishmaniasis: LIPOSOMAL AMPHOTERICIN B dose depends on formulation – see BNF. Test dose may be needed then loading dose. Use under specialist advice only. Highly toxic. Note liposomal form is less nephrotoxic and is dosed differently to other forms of Amphotericin which can be a source of serious errors. SE: fever, rigors, AKI, anaemia, phlebitis, low Mg, low K, cardiotoxic.

AMPICILLIN (broad spectrum bactericidal β-lactam antibiotic). UTI, chest, CAP, salmonella, listeria: AMPICILLIN 500 mg to 1 g PO/IM 6 h (oral absorption can be poor). Severe infection, endocarditis: AMPICILLIN 2 g slow IV 4–6 h. (Listeria meningitis treat for 21 days.) Infuse with 100 ml G5 or NS over 30 min. SE: APX, N, V, D, rash with infectious mononucleosis, cholestasis. Increases INR with warfarin. Avoid if diagnosis may be glandular fever type illness.

APIXABAN (Factor Xa inhibitor). Orthopaedic VTE prophylaxis: APIXABAN 2.5 mg BD PO duration. Hip surgery 32–38 days. Knee surgery 10–14 days. DVT/PE: APIXABAN 10 mg BD ×7 days, then 5 mg BD PO. Non-valvular AF: APIXABAN 5 mg BD PO. SE: bleeding, N, R. Caution: lower dose for AF to 2.5 mg 12 h if age >80, weight ≤60 kg or creatinine ≥133 micromol/litre or on ketoconazole, itraconazole, ritonavir, clarithromycin (see BNF).

ARTESUNATE. Complicated falciparum malaria under specialist advice: ARTESUNATE 2.4 mg/kg IV at 0, 12 and 24 h. Repeat daily until blood film clear. SE: QTc prolongation, bradycardia, N, V, D, H. Dilute with NS or G5. Take expert advice. If not available use IV quinine.

ASPIRIN (Cox inhibitor). Ischaemic stroke: ASPIRIN 300 mg for 14 days then 75 mg. ACS/stent/IHD: ASPIRIN 75–300 mg OD. SE: gastric irritation, PUD, asthma, tinnitus, toxicity. Caution: bleeding disorder, allergy, PUD, asthma. Check with cardiologists before stopping early post stenting.

ATENOLOL (β receptor blocker). ACS/post MI/arrhythmias: ATENOLOL 2.5–5 mg slow IV over 5–10 min. May be repeated after 15 min. Then ATENOLOL 25–100 mg/day. SE: bronchospasm, fatigue, depression, cold peripheries, ↓HR. Do not increase if CCF worsening. Caution: avoid in asthma, ↓HR, heart block, heart failure, pulmonary oedema.

ATORVASTATIN (HMG CoA reductase inhibitor). IHD, ischaemic stroke, hyperlipidaemia: ATORVASTATIN 10–80 mg OD. Monitor: LFTs and CK. SE: muscle toxicity seen with all statins – check CK (stop if >×5 increase), pancreatitis. Myopathy with macrolides or amiodarone. Liver disease, high K. Check LFT day 0, and 3 and 12 months. Check interactions.

ATROPINE. Severe bradycardia: ATROPINE 500 mcg (0.5 mg) every 3–5 minutes; max 3 mg. Organophosphate toxicity: ATROPINE 2–3 mg IV large doses needed. SE: mydriasis, ↑HR, N&V, dry warm skin, urinary retention, bronchodilation. Caution with MG, ileus. Do not use in asystolic arrest. SE: dry mouth, urine retention, and constipation. Confusion, mydriasis, dry airways, skin dryness and flushing. Angle closure glaucoma. Cautions: urine obstruction/ BPH. Avoid with cardiac transplant as denervated heart.

AZATHIOPRINE (purine antimetabolites). IBD/autoimmune conditions: AZATHIOPRINE 2–2.5 mg/kg daily PO/IV (some patients require less); adjusted according to response. SE: headache, myalgia, bone marrow suppression, alopecia. Commoner in those with low TPMT activity who need dose reduction. Hepatotoxicity and pancreatitis occur. Monitor LFT/FBC every 2–3 months. Myelosuppression with Allopurinol.

AZITHROMYCIN (macrolides). RTI, CAP, syphilis, chlamydia, legionella, mycoplasma. AZITHROMYCIN 500 mg to 1 g OD. COPD infection prevention: 250–500 mg three times per week long term. SE: N, V, R, long QT, abnormal LFTs.

BENDROFLUMETHIAZIDE (thiazide). HTN, CCF: BENDROFLUMETHIAZIDE 2.5–5 mg OD (standard 2.5 mg preferred). SE: low Na, low K/Mg, high Ca/urate/glucose, palpitations. Acute gout. Aim for K 4.0–5.0 mmol/L in cardiac patients.

BENZYLPENICILLIN (β-lactam bactericidal). Meningococcal/pneumococcal meningitis, endocarditis, pneumococcus, cellulitis: BENZYLPENICILLIN 1.2–2.4 g 4–6 h in 100 ml over 30 min IV with G5/NS or IM. SE: APX, N, V, D, R, convulsions (high dose), renal impairment. Caution: penicillin allergy. Not for intrathecal route.

BICARBONATE (SODIUM). TCA overdose, severe hyperkalaemia: 50 ml 8.4% BICARBONATE over 30–60 min or 250 ml 1.26% over 30–60 min. NB. 8.4% solution contains 1 mmol of HCO3– per ml and is very hypertonic and requires central venous access, so the more dilute form is preferred, which may be repeated depending on VBG, response and K. AKI with metabolic acidosis, rhabdomyolysis, salicylate overdose with metabolic acidosis: 500 ml 1.26% BICARBONATE or 100 ml of 8.4% over 2–4 h. Watch for overload/LVF, monitor VBG and titrate to urine pH and blood bicarbonate. Alkaline diuresis: 500 ml 1.26% BICARBONATE or 100 ml of 8.4% over 2–4 h until urine pH >7.5. Forced alkaline diuresis involves giving larger volumes. DKA: not used without senior advice.

BISOPROLOL (β receptor blocker). Stable CCF, angina: BISOPROLOL 1.25–10 mg PO OD. See Atenolol for more info.

BUMETANIDE (loop diuretic). CCF, HTN. BUMETANIDE 1–2 mg PO/IV OD. SE: diuresis, incontinence, low K, low Na, low BP, gynaecomastia, urinary retention, AKI.

CALCIUM. K >6.5 mmol/L, severe low Ca, tetany, high Mg, CCB toxicity: 10–20 ml 10% CALCIUM GLUCONATE/CHLORIDE with plasma-calcium/ECG monitoring. The chloride form contains more calcium but is more irritating to veins so gluconate usually preferred. Flush lines after. Maintenance: CALCIUM GLUCONATE 100 ml of 10% in 1 L of G5 or NS. Give 50 ml/h until symptoms resolved or [Ca] >1.9 mmol/L. CaCl2 is often found as min-I-jet on arrest trolley. Use gluconate if prolonged infusion needed. C/I: digoxin toxicity. Do not give calcium in same line as bicarbonate or phosphate as precipitates.

CANDESARTAN (ARB). HTN, heart failure, diabetic nephropathy, CKD with proteinuria, post MI: CANDESARTAN 4 mg (CCF) 8–32 mg PO OD. Start low dose in heart failure. Gradually titrate dose depending on BP and symptoms. Watch U&E at 1–2 weeks. First dose ↓BP so start at night. SE: N, V, H, D, R, ↑K, low BP, AKI (esp. with RAS). Angioedema less common than with ACEI. Cautions: severe aortic stenosis (relative), renal artery stenosis (develop AKI), low Na, mitral stenosis, HOCM, ↓BP, ↑K with other potassium retaining drugs. Avoid in pregnancy as teratogen. Avoid NSAIDs.

CAPTOPRIL (ACEI). BP, HTN, heart failure (lowest dose), diabetic nephropathy, CKD with proteinuria, post MI: CAPTOPRIL 6.25–12.5 mg BD (max 50 mg TDS). NB. Gradually titrate dose depending on BP and symptoms. Watch U&E at 1–2 weeks. First dose ↓BP so start at night. SE: N, V, H, D, R, cough, angioedema, ↑K, altered taste, low BP, AKI. AKI might suggest renal artery stenosis. Cautions: severe aortic stenosis (relative), HOCM, low Na, ↓BP, high K with other potassium retaining drugs. Caution as teratogenic. Avoid NSAIDs.

CARBAMAZEPINE (AED) Epilepsy: CARBAMAZEPINE 100–200 mg 1–2 times/day, increased by 100–200 mg every 2 weeks; usual dose 1 g/d in divided doses; max dose 1.6–2 g daily in divided doses. SE: Sedation, Rash, SJS, oedema, low Na, N, V, vertigo, diplopia, aplastic anaemia. Can worsen myoclonic/absence seizures. Avoid with MAOIs. See BNF for interactions. Induces its own metabolism so levels drop at 3 weeks. Need to titrate dose. Expert advice in pregnancy.

CARBIMAZOLE (antithyroid). Hyperthyroidism: CARBIMAZOLE 15–40 mg/d for 4–8 weeks until euthyroid. Then reduce to 5–15 mg daily. Give for 12–18 months or CARBIMAZOLE 40–60 mg/day + THYROXINE for 18 months (block and replace). Given in divided dose. SE: rash, agranulocytosis. Give written warning to patient: any fever, sore throat stop drug and seek medical help. PTU preferred in pregnancy.

CARVEDILOL (β receptor blocker). Stable CCF: CARVEDILOL 3.125 mg od slowly up titrated to 25 mg BD PO. See Atenolol for C/I and SE.

CEFOTAXIME (3rd gen cephalosporin, penetrates CSF). Bacterial meningitis, sepsis, cholangitis, epiglottitis, typhoid, UTI: CEFOTAXIME 1–2 g slow IV/IM 6 h (meningitis 8 g/day). SE: R, N, V, D, C. difficile colitis, arrhythmias. Caution: reduce dose in renal failure, avoid neurotoxic drugs. See Ceftriaxone on penicillin allergy.

CEFTRIAXONE (3rd gen cephalosporin, penetrates CSF). Bacterial meningitis, HACEK endocarditis, CAP/HAP, sepsis, etc.: CEFTRIAXONE 1–2 g IM/IV BD. OD in less severe infections. SE: R, N, V, D, APX, pancreatitis. Avoid if history of immediate hypersensitivity or anaphylaxis to penicillin. Reduce dose in AKI/CKD.

CEFUROXIME (2nd gen cephalosporin). Epiglottitis, pneumonia, UTI, surgical, soft tissue: CEFUROXIME 750 mg to 1.5 g IV/IM 8 h. UTI, chest, mild to moderate infection: CEFUROXIME 250–500 mg BD PO. SE: R, N, V, D, APX, C. difficile colitis. See Ceftriaxone on penicillin allergy.

CEPHALEXIN (1st gen cephalosporin). CAP, UTI: CEPHALEXIN 250 mg 8 h PO (max 4 g/day) SE: R, N, V, APX. See Ceftriaxone on penicillin allergy.

CHLOROQUINE. Non-falciparum malaria: CHLOROQUINE 620 mg, then 310 mg after 6 h, then 310 mg on days 2 and 3; total dose 25 mg/kg of base, and PRIMAQUINE 15–30 mg OD in vivax and ovale for 14 days. Take expert guidance. Primaquine may cause haemolysis in G6PD-deficient individuals. Can worsen MG, psoriasis and epilepsy.

CHLORPHENAMINE (sedating antihistamine). Anaphylaxis: CHLORPHENAMINE 10 mg slow IV/IM 6 h/PRN. SE: sedation, blurred vision, dry mouth, retention, glaucoma. Allergy: CHLORPHENAMINE 4 mg 6 h PO. SE: antimuscarinic, sedation.

CHLORPROMAZINE (antipsychotic). Acute psychosis/mania: CHLORPROMAZINE 25–50 mg TDS PO/deep IM. Titrate to response (max 300 mg/d) SE: see Haloperidol.

CIPROFLOXACIN (Quinolone). Gram-negative infections. pseudomonas, typhoid, traveller’s diarrhoea, gonorrhoea, UTI, anthrax: CIPROFLOXACIN 500–750 mg 12 h PO 400 mg 12 h IV over 30–60 min. SE: N, V, D, flatulence, syncope, oedema, erythema nodosum, tendonitis, long QT, insomnia, epilepsy. Avoid in pregnancy, G6PD, seizures, MG. NSAIDs, Ciclosporin. Reduce dose in AKI/CKD. Risk of theophylline toxicity, Increases INR with warfarin. ↑LFTs.

CITALOPRAM (SSRI). Depression: CITALOPRAM 10–60 mg OD. SE: N, V, H, sedation, insomnia, impotence. Low Na, hepatitis, avoid MAOIs. Slowly increase dose. Avoid abrupt withdrawal. See Fluoxetine.

CLARITHROMYCIN (macrolide). UTI, CAP, pertussis, legionella, campylobacter, penicillin allergy, Lyme disease: CLARITHROMYCIN 250–500 mg BD PO or CLARITHROMYCIN 500 mg 12 h IV. SE: dyspepsia, N, V, H, insomnia, porphyria, liver failure. Long QT. Inhibits p450 so ↑levels of theophylline, ciclosporin, digoxin, carbamazepine. Caution with other drugs causing long QT, porphyria, liver failure. Caution with atorvastatin and avoid with simvastatin. Review dose in AKI/CKD.

CLINDAMYCIN (lincosamide antibiotic). TSS, Gram+ve cocci, streptococci, staphylococci, anaerobes: CLINDAMYCIN 150–450 mg 6 h PO OR CLINDAMYCIN 0.6–2.7 g/d in 2–4 doses deep IM or IV infusions. SE: antibiotic-associated colitis, N, R, D, oesophagitis, jaundice, APX, SJS/TEN. Cautions: diarrhoea. Watch U&E and LFTs if treatment >10 days.

CLOPIDOGREL (P2Y12 receptor blocker). Prodrug: STEMI/ACS: CLOPIDOGREL 300–600 mg loading dose. Usual dose 300 mg PO and then 75 mg OD. Post-TIA /ischaemic stroke: CLOPIDOGREL 300 mg PO and then 75 mg OD. SE: bleeding – takes 7 days for effect to reduce. Effects reduced by omeprazole. Caution: active bleeding, trauma, imminent surgery. Ask cardiologist before stopping dual antiplatelet early post stenting.

CO-AMOXICLAV (AUGMENTIN). Amoxicillin and clavulinic acid. Mild/moderate CAP, UTI, listeria: CO-AMOXICLAV (250/125) 375–625 mg 8 h PO or CO-AMOXICLAV 1.2 g IV 8 h. SE: anaphylaxis, N, V, D, cholestasis, hepatitis, rash with infectious mononucleosis. Caution: avoid if glandular fever type illness. Increases INR with warfarin.

CODEINE (opioid). Analgesia, diarrhoea, cough suppressant: CODEINE 8–60 mg 4–6 h. SE: delirium, constipation, N, V. Beware opiate toxicity. Consider Naloxone. Some genetically predisposed to toxicity.

COLCHICINE (inhibits mitosis). Acute gout: COLCHICINE 1 mg stat PO then 0.5 mg 4 h (max dose of 6 mg taken or diarrhoea). A low dose COLCHICINE 0.5 mg 12 h may be given for weeks with allopurinol. Acute and recurrent pericarditis: COLCHICINE 0.5–2 g daily. SE: D, N, V, GI bleed. Toxic with Ciclosporin, Erythromycin, statin, others (see BNF). Avoid in pregnancy, AKI/CKD. Avoid if abnormal renal or hepatic function. Avoid with macrolide antibiotics, which alter its metabolism.

COLESTYRAMINE. Gallstones when surgery not possible: COLESTYRAMINE 4 g sachets BD in water (max 24 g/d). Delay taking other drugs for several hours after. SE: constipation. Poorly tolerated.

CO-TRIMOXAZOLE. Trimethoprim:sulfamethoxazole in 1:5 ratio (80:400). PCP: CO-TRIMOXAZOLE 120 mg/kg daily in 2–4 divided doses for 14–21 days usually given with steroids. PCP prophylaxis: CO-TRIMOXAZOLE 960 mg OD PO. SE: allergy, SJS, N, V, agranulocytosis, aplastic anaemia. ↑INR if Warfarin. Phenytoin, Ciclosporin, Azathioprine, Mercaptopurine, Methotrexate toxicity. Check BNF.

CYCLIZINE. Severe nausea: CYCLIZINE 50 mg slow IV/IM/PO 8 h. SE: sedation, dry mouth, urinary retention, N, V. Avoid in CCF/ACS.

DABIGATRAN (direct thrombin inhibitor). Non-rheumatic AF/PE/DVT: Adult 18–74 years DABIGATRAN 150 mg BD. Adult 75–79 years 110–150 mg BD. Adult ≥80 years 110 mg BD. PE/DVT patients need first 5 days covered with parenteral anticoagulant, e.g. LMWH. SE: bleeding, indigestion (try taking with food or switch to other DOAC). Active bleeding, falls, renal failure. See BNF or datasheet. Reduce dose with Amiodarone or Verapamil, Quinine. Do not keep in dosette box.

DALTEPARIN (LMWH). VTE prophylaxis: DALTEPARIN 2500 units SC pre surgery, then 2500 units OD. Medical patients: DALTEPARIN 5000 units SC 24 h. NSTEMI/unstable angina: DALTEPARIN 120 units/kg BD (max. 10000 units BD) for up to 8 days. PE/DVT: DALTEPARIN (FRAGMIN) 200 units/kg SC OD (max. per dose 18 000 units). CI and SE, see Enoxaparin.

DEMECLOCYCLINE (tetracycline). SIADH: DEMECLOCYCLINE 300–600 mg BD. If water restriction not tolerated or ineffective. Induces nephrogenic diabetes insipidus. SE/cautions: see tetracyclines. Avoid in pregnancy and children. SE: AKI, photosensitive rashes.

DESFERRIOXAMINE (chelating agent). Iron, aluminium toxicity: DESFERRIOXAMINE 15 mg/kg/h (max 80 mg/kg/24 h). SE: IM use can be painful, ARDS, abdominal pain, APX is rare, low BP if rapid infusion. Chelated iron causes red urine, risk of yersinia and mucormycosis infections.

DIAZEPAM (benzodiazepine). Acute sedation/severe anxiety: DIAZEPAM 1–5 mg PO/IV/PR depending on urgency. SE: oversedation is always the concern especially with parenteral administration and ensure facilities to resuscitate and manage airway are available. Status epilepticus: DIAZEPAM 10 mg, then 10 mg after 10 mins if needed. Give slowly at rate of 5 mg/min. If no IV access can give same dose PR with a 5 ml syringe connected to a rectal tube introduced 4–5 cm into the rectum. Acute alcohol withdrawal/delirium tremens: DIAZEPAM 5–10 mg TDS PO in severe cases when urgent sedation needed. Avoid neuroleptics. SE: dependence, tolerance, amnesia. Withdrawal symptoms.

DIGOXIN. Rate control AF, CCF: loading dose: DIGOXIN 0.75–1.5 mg split in 3 doses PO over 24 h, e.g. 0.5 mg × 3. Lower dose in the lean and elderly. Urgent loading

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