Comprehensive Pharmaceutical Study Guide: Analgesics, GI, and Dermatological Agents

Central Analgesic and Antipyretic Agents

Paracetamol, also known by the trade name Tylenol, acts as a central analgesic and antipyretic. While it is highly effective for managing mild to moderate pain and fever, it possesses a minimal anti-inflammatory effect. The standard dosage for Paracetamol ranges from $325-1000\,mg$ administered every $4-6\,h$ as needed (PRN). It is critical to observe a maximum daily limit of $4\,g/day$ and a treatment duration not exceeding $5\,days/course$ to avoid hepatotoxicity, which can occur during overdose or chronic use situations.

Traditional Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)

Ibuprofen is a traditional NSAID used for mild to moderate pain, inflammation, and fever. The dosage is typically $200-800\,mg$ every $6-8\,h$, with a maximum daily intake of $3,200\,mg/day$. Cautions associated with Ibuprofen include dyspepsia, gastrointestinal (GI) bleed, fluid retention, renal injury, increased cardiovascular (CV) risk, and bronchospasm.

Diclofenac, available under trade names such as Voltaren, Cataflam, and Volfast, is another traditional NSAID indicated for mild to moderate pain and inflammation. The recommended dosage is $25-50\,mg$ administered twice a day ($BID$) or three times a day ($TID$), ensuring not to exceed $150\,mg/day$. It shares the same risk profile as Ibuprofen, including GI bleeding, renal injury, and increased CV risk.

Naproxen, sold under trade names Synflex, Naprosyn, and Naprosyn LE, is used for mild to moderate pain and inflammation. The dosage is $250-500\,mg$ $BID$, with a maximum limit of $1,500\,mg/day$. Like other traditional NSAIDs, it requires caution regarding dyspepsia, fluid retention, and bronchospasm.

Indomethacin is a traditional NSAID for mild to moderate pain and inflammation. The dosage is $25-50\,mg$ $BID$ or $TID$, with a maximum of $200\,mg/day$. Side effects include GI distress, renal injury, and cardiovascular risks.

Mefenamic acid, commonly known as Ponstan, is used for mild to moderate pain and inflammation. The execution protocol involves an initial dose of $500\,mg$ followed by $250\,mg$ every $6\,h$, not exceeding a total of $1,500\,mg/day$. Risks include dyspepsia, GI bleeding, and fluid retention.

Meloxicam, traded as Mobic, is a traditional NSAID used for mild to moderate pain and inflammation. The dosage is $7.5-15\,mg$ once daily ($OD$), which is also the maximum daily dose of $15\,mg/day$. It carries risks of renal injury and increased CV risk.

COX-2 Specific NSAIDs

Celecoxib, marketed as Celebrex, is a COX-2 specific NSAID indicated for mild to moderate pain and inflammation. The dosage is $200\,mg$ $OD$ or $BID$, with a maximum cap of $400\,mg/day$. Cautions include dyspepsia, GI bleed, fluid retention, renal injury, and increased CV risk.

Etoricoxib, known as Arcoxia, is also a COX-2 specific NSAID for mild to moderate pain and inflammation. The dosage ranges from $60-120\,mg$ $OD$, where the maximum dosage is $120\,mg/day$. It shares the side effect profile of other COX-2 inhibitors.

Skeletal Muscle Relaxants and Antispasmodics

Baclofen, sold under the trade name Lioresal, serves as a GABA-B agonist used to treat spasticity. The dosage is $5-10\,mg$ $TID$, with a maximum dose of $80\,mg/day$. Side effects include sedation, weakness, and dizziness.

Tizanidine, traded as Sirdalud, is a central $\alpha_2-agonist$ used for spasticity. The dosage is $2-4\,mg$ $TID$, with a maximum allowance of $36\,mg/day$. Potential adverse effects include sedation, hypotension, dry mouth, and liver injury.

Orphenadrine/Paracetamol, known as Norgesic, acts as an anticholinergic and NMDA antagonist combined with an analgesic. It is used for muscle spasms accompanied by pain. The execution involves taking $1-2\,tablets$ two to three times per day, with a maximum of $6\,tablets/day$. Cautions include sedation and anticholinergic effects.

Eperisone, sold as Myonal, functions as a voltage-gated sodium and calcium channel blocker for muscle spasms. The dose is $50\,mg$ administered $1-3\times/day$, with a maximum of $150\,mg/day$. Side effects include sedation, dizziness, weakness, and GI upset.

Tolperisone, traded as Mydocalm, also acts as a voltage-gated sodium and calcium channel blocker for muscle spasms. The dosage is $150\,mg$ taken $1-3\times/day$, with a maximum dose of $450\,mg/day$. Cautions include dizziness, sedation, and gastrointestinal upset.

Treatments for Gout, Inflammation, and Osteoarthritis

Colchicine is used to inhibit microtubules and neutrophil-mediated inflammation during acute gout flares and for gout flare prophylaxis. For a flare, the dose is $1.2\,mg$ followed by $0.6\,mg$ one hour later. For prophylaxis, the dose is $0.6\,mg$ $OD$ or $BID$. Side effects include diarrhea, nausea, myopathy, and bone marrow suppression.

Allopurinol, available as Zyloric, is a xanthine oxidase inhibitor used for chronic gout or urate-lowering therapy. The dosage is $50-800\,mg\,OD$. It carries risks of rash, GI upset, and severe cutaneous adverse reactions (SCARs).

Febuxostat, known as Feburic, is another xanthine oxidase inhibitor for chronic gout or urate-lowering therapy. The dose is $40-80\,mg\,OD$. Cautions include LFT (liver function test) elevation, rash, and increased CV risk.

Prednisolone is a systemic corticosteroid used for acute inflammatory and allergic disorders. Short courses involve $5-60\,mg/day$ for approximately $3-7\,days$. Adverse effects include hyperglycemia, mood changes, infection risk, and dyspepsia.

Glucosamine, traded as Viatril-S, is a cartilage matrix precursor used for osteoarthritis. The standard dose is $1500\,mg/day$. It may cause GI upset and headache.

Diacerein, marketed as Artrodar, is an IL-1 modulator for osteoarthritis management. The dosage is $50\,mg$ $OD$ or $BID$. Side effects include diarrhea, urine discoloration, and hepatotoxicity.

Proton Pump Inhibitors (PPIs) and H2-Receptor Antagonists

Proton pump inhibitors (PPIs) are indicated for GERD, peptic ulcer disease, and NSAID ulcer prophylaxis. They share common cautious side effects including headache, diarrhea, low Magnesium ($Mg$) or Vitamin $B12$, fractures, and Clostridioides difficile infection. Specific PPIs include: Omeprazole ($20-40\,mg\,OD$); Esomeprazole (Nexium, $20-40\,mg\,OD$); Rabeprozole (Pariet, $20\,mg\,OD$); and Lansoprazole (Prevacid, $15-30\,mg\,OD$).

Histamine H2-receptor antagonists are also used for GERD, peptic ulcer disease, and NSAID ulcer prophylaxis. Famotidine (Pepfamin) is dosed at $20\,mg\,BID$ or $40\,mg\,hs$ (at bedtime); it may cause confusion in frail patients or those with renal impairment. Cimetidine (Siamdine) is dosed at $400\,mg\,BID$ or $800\,mg\,hs$ and may lead to gynecomastia, confusion, and various drug interactions.

Vonoprazan, known as Vocinti, is a potassium-competitive acid blocker used for GERD and peptic ulcer disease. The dose is $20\,mg\,OD$, and side effects include diarrhea and constipation.

Antacids and Mucosal Protectants

Sodium bicarbonate, sold as Sodamint, neutralizes gastric acid for short-term relief of heartburn or dyspepsia. The dosage is $325-2000\,mg$ after meals or at bedtime ($PRN$). Adverse effects include belching, bloating, hypernatremia, and metabolic alkalosis.

Aluminum hydroxide, known as Alum-milk, neutralizes gastric acid for heartburn relief. The dosage is $500-1500\,mg$ after meals and at bedtime ($PRN$). It can lead to constipation and hypophosphatemia.

Magnesium hydroxide, referred to as Milk of magnesia, serves as an antacid or osmotic laxative. As an antacid, the dose is $400-1200\,mg$ every $6\,h$ ($PRN$). As a laxative, the dose is $2.4-4.8\,g\,OD\,hs$. It may cause diarrhea and hypermagnesemia in patients with renal impairment.

Alginate/Sodium bicarbonate/Calcium carbonate, marketed as Gaviscon, creates an alginate raft barrier along with neutralizing acid for GERD. The dosage is $10-20\,mL$ or $1-2\,tablets$ four times a day ($QID$). It may cause bloating, nausea, or hypernatremia.

Sucralfate, known as Ulsanic, provides a protective barrier for peptic ulcer disease and gastritis. The dose is $1\,g\,QID$. Adverse effects include constipation and aluminum accumulation in cases of renal failure.

Gastrointestinal Prokinetics and Antiemetics

Metoclopramide, traded as Plasil, is a D2 antagonist used as an antiemetic and prokinetic. The dosage is $10\,mg$ $TID-QID$. Adverse effects include drowsiness, diarrhea, extrapyramidal symptoms, and hyperprolactinemia.

Domperidone, sold as Motilium-M, is also a D2 antagonist for antiemetic and prokinetic purposes. The dose is $10\,mg\,TID$. It carries risks of QT prolongation, arrhythmia, and dry mouth.

Itopride (Ganaton) acts as a D2 antagonist and acetylcholinesterase inhibitor for functional dyspepsia or IBS. The dose is $50\,mg\,TID$. Side effects include diarrhea, abdominal pain, and hyperprolactinemia.

Ondansetron (Onsia) is a 5-HT3 antagonist antiemetic used for nausea and vomiting. The dose is $4-8\,mg$ two to three times a day ($PRN$). Cautions include constipation, headache, and QT prolongation.

Antispasmodics and Antiflatulents

Simethicone (Air-X) is an antiflatulent for bloating and gas discomfort. The dose is $80-160\,mg$ given $1-4\times/day$ ($PRN$). It may cause belching.

Dicyclomine/Simethicone (Berclomin) combines an antimuscarinic antispasmodic with an antiflatulent for abdominal cramps or IBS. The dosage is $1-2\,tablets$ three to four times daily ($PRN$). Side effects include dry mouth, blurred vision, constipation, and dizziness.

Hyoscine butyl bromide (Buscopan) is an antimuscarinic antispasmodic for IBS and abdominal cramps. The dose is $10-20\,mg$ three to four times daily ($PRN$). Cautions include dry mouth, blurred vision, tachycardia, and constipation.

Mebeverine (Colofac) is a musculotropic antispasmodic for IBS. The dosage is $135\,mg\,TID$ or a modified release ($MR$) version of $200\,mg\,BID$. It may cause dizziness.

Laxatives and Antidiarrheals

Lactulose (Duphalac) is an osmotic laxative used for constipation and hepatic encephalopathy (HE). For constipation, the dose is $15-30\,mL\,OD$. For HE, the dose is $15-45\,mL$ two to three times daily. It can cause bloating, flatulence, and diarrhea.

Polyethylene glycol 4000 (Macrogol 4000), known as Forlax, is an osmotic laxative. The dose is $10-20\,g$ in water $OD$. Higher doses are used for bowel prep. Side effects include bloating and nausea.

Bisacodyl (Dulcolax) is a stimulant laxative dosed at $5-10\,mg\,OD\,hs\,PRN$. It may cause cramps, diarrhea, and hypokalemia if overused.

Senna (Senokot) is a stimulant laxative dosed at $7.5-15\,mg\,OD\,hs\,PRN$. Chronic use can lead to melanosis coli.

Ispaghula husk (Fybogel, Mucilin) is a bulk-forming fiber laxative. The dose is $1-2\,sachets$ or $2-4\,tsp$ in water $1-3\times/day$. It may cause bloating or obstruction if taken without adequate water.

Loperamide (Imodium) is a peripheral $\mu-opioid$ agonist for diarrhea or IBS-D. The initial dose is $4\,mg$, followed by $2\,mg$ after each loose stool, with a maximum of $16\,mg/day$. Overdose can cause serious arrhythmia.

Topical Corticosteroids for Skin Disorders

Hydrocortisone cream is a low-potency topical corticosteroid for skin inflammation. It should be applied thinly $1-2\times/day$. Risks include skin atrophy, striae, acneiform eruption, telangiectasia, and HPA suppression if used extensively.

Moderate-potency topical corticosteroids for skin inflammation include Triamcinolone acetonide cream (Aristocort, Aristocort-A), Mometasone cream (Elomet), and Betamethasone valerate cream (Betnovate). Generally, these are applied thinly once or twice daily. Mometasone specifically is applied once daily.

Desoximetasone lotion (Topicort) is a high-potency topical steroid applied thinly $1-2\times/day$. Clobetasol cream (Dermovate) is a very high-potency topical steroid applied thinly $1-2\times/day$ for a short course only. Both carry standard corticosteroid risks such as skin atrophy and HPA suppression.

Specialized Topical and Oral Skin Treatments

Crisaborole ointment (Staquis) is a topical PDE4 inhibitor for mild to moderate atopic dermatitis, applied $BID$. It may cause burning or stinging at the application site.

Benzoyl peroxide gel (Benzac) is an antimicrobial and comedolytic for acne vulgaris. It is applied thinly $1-2\times/day$ and washed off after $15-30\,mins$. It can cause dryness and irritation.

Topical retinoids for acne and photoaging include Tretinoin cream (Retacnyl), Adapalene gel (Differin), and Trifarotene cream (Aklief, an RAR-$\gamma$ selective retinoid). These are applied nightly and may cause dryness, peeling, and photosensitivity.

Clindamycin solution (Dalacin-T) is a topical lincosamide antibiotic for inflammatory acne, applied $BID$. It should not be used alone to avoid resistance.

Azelaic acid cream (Skinoren) is a keratolytic, anti-inflammatory, and antimicrobial used for acne, rosacea, and post-inflammatory hyperpigmentation. It is applied $BID$.

EpiDuo is a combination of Benzoyl peroxide and Adapalene gel used once nightly for acne vulgaris.

Isotretinoin (Roaccutane, Acnotin) is an oral retinoid for severe or refractory acne. The dose is $0.5-1\,mg/kg/day$. It is teratogenic and requires monitoring for cheilitis, elevated LFT/TG (triglycerides), and mood changes.

Treatments for Psoriasis and Atopic Dermatitis

Calcipotriol cream (Daivonex) is a Vitamin D analog that reduces keratinocyte proliferation in plaque psoriasis. It is applied $BID$. Rare hypercalcemia can occur if used excessively.

Daivobet and Xamiol are combinations of Calciprotriol and Betamethasone dipropionate (a potent corticosteroid) for plaque psoriasis, applied once daily.

Tacrolimus ointment (Protopic) and Pimecrolimus ointment (Elidel) are topical calcineurin inhibitors for atopic dermatitis, applied $BID$. They may cause local burning, stinging, or irritation.