With the development of proton pump inhibitors, such as omeprazole, approved for the same indications, cimetidine is available as an over-the-counter formulation to prevent heartburn or acid indigestion, along with the other H2-receptor antagonists.[12]
Cimetidine was developed in 1971 and came into commercial use in 1977.[13][14] Cimetidine was approved in the United Kingdom in 1976,[citation needed] and was approved in the United States by the Food and Drug Administration in 1979.[15]
Cimetidine affects the metabolism of methadone, sometimes resulting in higher blood levels and a higher incidence of side effects, and may interact with the antimalarial medication hydroxychloroquine.[21]
Cimetidine is a potent inhibitor of tubular creatinine secretion. Creatinine is a metabolic byproduct of creatine breakdown. Accumulation of creatinine is associated with uremia, but the symptoms of creatinine accumulation are unknown, as they are hard to separate from other nitrogenous waste buildups.[23]
Like several other medications (e.g., erythromycin), cimetidine interferes with the body's metabolization of sildenafil, causing its strength and duration to increase and making its side effects more likely and prominent.[citation needed]
Clinically significant drug interactions with the CYP1A2 substrate theophylline, the CYP2C9 substrate tolbutamide, the CYP2D6 substrate desipramine, and the CYP3A4 substrate triazolam have all been demonstrated with cimetidine, and interactions with other substrates of these enzymes are likely as well.[24]
At typical therapeutic levels, cimetidine has either no effect on or causes small increases in circulating testosterone concentrations in men.[45] Any increases in testosterone levels with cimetidine have been attributed to the loss of negative feedback on the HPG axis that results due to AR antagonism.[45][46] At typical clinical dosages, such as those used to treat peptic ulcer disease, the incidence of gynecomastia (breast development) with cimetidine is very low at less than 1%.[53][45] In one survey of over 9,000 patients taking cimetidine, gynecomastia was the most frequent endocrine-related complaint but was reported in only 0.2% of patients.[45] At high doses however, such as those used to treat Zollinger–Ellison syndrome, there may be a higher incidence of gynecomastia with cimetidine.[53] In one small study, a 20% incidence of gynecomastia was observed in 25 male patients with duodenal ulcers who were treated with 1,600 mg/day cimetidine.[52] The symptoms appeared after 4 months of treatment and regressed within a month following discontinuation of cimetidine.[52] In another small study, cimetidine was reported to have induced breast changes and erectile dysfunction in 60% of 22 men treated with it.[52] These adverse effects completely resolved in all cases when the men were switched from cimetidine to ranitidine.[52] A study of the United KingdomGeneral Practice Research Database, which contains over 80,000 men, found that the relative risk of gynecomastia in cimetidine users was 7.2 relative to non-users.[52] People taking a dosage of cimetidine of greater than or equal to 1,000 mg showed more than 40 times the risk of gynecomastia than non-users.[52] The risk was highest during the period of time of 7 to 12 months after starting cimetidine.[52] The gynecomastia associated with cimetidine is thought to be due to blockade of ARs in the breasts, which results in estrogen action unopposed by androgens in this tissue, although increased levels of estrogens due to inhibition of estrogen metabolism is another possible mechanism.[52] Cimetidine has also been associated with oligospermia (decreased sperm count) and sexual dysfunction (e.g., decreased libido, erectile dysfunction) in men in some research, which are hormonally related similarly.[46][45][52]
In accordance with the very weak nature of its AR antagonistic activity, cimetidine has shown minimal effectiveness in the treatment of androgen-dependent conditions such as acne, hirsutism (excessive hair growth), and hyperandrogenism (high androgen levels) in women.[54][55][53][56] As such, its use for such indications is not recommended.[55][56]
Cimetidine, approved by the FDA for inhibition of gastric acid secretion, has been advocated for a number of dermatological diseases.[57] Cimetidine was the prototypical histamine H2 receptor antagonist from which the later members of the class were developed. Cimetidine was the culmination of a project at Smith, Kline and French (SK&F) Laboratories in Welwyn Garden City (now part of GlaxoSmithKline) by James W. Black, C. Robin Ganellin, and others to develop a histamine receptorantagonist to suppress stomach acid secretion.[58] This was one of the first drugs discovered using a rational drug design approach. Sir James W. Black shared the 1988 Nobel Prize in Physiology or Medicine for the discovery of propranolol and also is credited for the discovery of cimetidine.
At the time (1964), histamine was known to stimulate the secretion of stomach acid, but also that traditional antihistamines had no effect on acid production. In the process, the SK&F scientists also proved the existence of histamine H2 receptors.
The SK&F team used a rational drug-design structure starting from the structure of histamine — the only design lead, since nothing was known of the then hypothetical H2 receptor. Hundreds of modified compounds were synthesized in an effort to develop a model of the receptor. The first breakthrough was Nα-guanylhistamine, a partial H2 receptor antagonist. From this lead, the receptor model was further refined and eventually led to the development of burimamide, the first H2 receptor antagonist. Burimamide, a specific competitive antagonist at the H2 receptor, 100 times more potent than Nα-guanylhistamine, proved the existence of the H2 receptor.
Burimamide was still insufficiently potent for oral administration, and further modification of the structure, based on modifying the pKa of the compound, led to the development of metiamide. Metiamide was an effective agent; it was associated, however, with unacceptable nephrotoxicity and agranulocytosis.[58] The toxicity was proposed to arise from the thiourea group, and similar guanidine analogues were investigated until the ultimate discovery of cimetidine. The compound was synthesized in 1972 and evaluated for toxicology by 1973. It passed all trials.
Cimetidine was first marketed in the United Kingdom in 1976, and in the U.S. in August 1977; therefore, it took 12 years from initiation of the H2 receptor antagonist program to commercialization. By 1979, Tagamet was being sold in more than 100 countries and became the top-selling prescription product in the U.S., Canada, and several other countries. In November 1997, the American Chemical Society and the Royal Society of Chemistry in the U.K. jointly recognized the work as a milestone in drug discovery by designating it an International Historic Chemical Landmark during a ceremony at SmithKline Beecham's New Frontiers Science Park research facilities in Harlow, England.[59]
The commercial name "Tagamet" was decided upon by fusing the two words "antagonist" and "cimetidine".[58] Subsequent to the introduction onto the U.S. drug market, two other H2 receptor antagonists were approved, ranitidine (Zantac, Glaxo Labs) and famotidine (Pepcid, Yamanouchi, Ltd.) Cimetidine became the first drug ever to reach more than $1 billion a year in sales, thus making it the first blockbuster drug.[citation needed]
Tagamet has been largely replaced by proton pump inhibitors for treating peptic ulcers, but is available as an over-the-counter medicine for heartburn in many countries.[59]
Research
Some evidence suggests cimetidine could be effective in the treatment of common warts, but more rigorous double-blind clinical trials found it to be no more effective than a placebo.[60][61][62]
Tentative evidence supports a beneficial role as add-on therapy in colorectal cancer.[63]
Cimetidine inhibits ALA synthase activity and hence may have some therapeutic value in preventing and treating acute porphyria attacks.[64][65]
There is some evidence supporting the use of Cimetidine in the treatment of PFAPA.[66]
Veterinary use
In dogs, cimetidine is used as an antiemetic when treating chronic gastritis.[67]
^Pino MA, Azer SA (March 2023). "Cimetidine". StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. PMID31334975. Bookshelf ID: NBK544255. Retrieved 6 November 2023 – via U.S. National Library of Medicine.
^See complete drug interactions for Zomig (zolmitriptan succinate used for migraine relief) in package insert: "Highlights of Zomig Prescribing Information"(PDF). AstraZeneca. Archived from the original(PDF) on 18 February 2015. Retrieved 28 January 2010.
^Urakami Y, Kimura N, Okuda M, Masuda S, Katsura T, Inui K (June 2005). "Transcellular transport of creatinine in renal tubular epithelial cell line LLC-PK1". Drug Metabolism and Pharmacokinetics. 20 (3): 200–205. doi:10.2133/dmpk.20.200. PMID15988122. S2CID13857940.
^ abcdeWilliams DA (2008). "Drug Metabolism". In Lemke TL, Williams DA (eds.). Foye's Principles of Medicinal Chemistry. Lippincott Williams & Wilkins. pp. 273–. ISBN978-0-7817-6879-5.
^Priskorn M, Larsen F, Segonzac A, Moulin M (1997). "Pharmacokinetic interaction study of citalopram and cimetidine in healthy subjects". European Journal of Clinical Pharmacology. 52 (3): 241–242. doi:10.1007/s002280050282. PMID9218934. S2CID22540140.
^Martínez C, Albet C, Agúndez JA, Herrero E, Carrillo JA, Márquez M, et al. (April 1999). "Comparative in vitro and in vivo inhibition of cytochrome P450 CYP1A2, CYP2D6, and CYP3A by H2-receptor antagonists". Clinical Pharmacology and Therapeutics. 65 (4): 369–376. doi:10.1016/S0009-9236(99)70129-3. PMID10223772. S2CID25151710.
^Delafuente JC (November 2003). "Understanding and preventing drug interactions in elderly patients". Critical Reviews in Oncology/Hematology. 48 (2): 133–143. doi:10.1016/j.critrevonc.2003.04.004. PMID14607376.
^ abCairns D (2012). "Drug Metabolism: Drug Conjugating Reactions (Phase 2)". Essentials of Pharmaceutical Chemistry. Pharmaceutical Press. pp. 110–. ISBN978-0-85369-979-8. Drugs interacting in this way with CYP include the histamine H2-receptor antagonist cimetidine, [...] Reversible inhibitors, such as cimetidine, which interact with the complexed iron at the active site of the enzyme to inhibit oxidation of other drugs. The inhibition occurs before any oxidation of the inhibitor occurs and is reversible once the inhibitor is removed.
^Liska DJ (June 1998). "The detoxification enzyme systems". Alternative Medicine Review. 3 (3): 187–198. PMID9630736. Cimetidine is an example of a compound that can bind directly to the heme iron of the cytochrome P450 reactive site to inhibit all cytochrome-dependent Phase I enzyme activities.13
^Jensen RT, Collen MJ, McArthur KE, Howard JM, Maton PN, Cherner JA, et al. (November 1984). "Comparison of the effectiveness of ranitidine and cimetidine in inhibiting acid secretion in patients with gastric hypersecretory states". The American Journal of Medicine. 77 (5B): 90–105. PMID6150641.
^Biagi P, Milani G (March 1985). "[Dysfunction of the hypothalamo-hypophyseal-gonadal axis induced by histamine H2 antagonists. Review of the literature and personal observations]". Minerva Medica (in Italian). 76 (12): 579–586. PMID3921876.
^Sivelle PC, Underwood AH, Jelly JA (March 1982). "The effects of histamine H2 receptor antagonists on androgen action in vivo and dihydrotestosterone binding to the rat prostate androgen receptor in vitro". Biochemical Pharmacology. 31 (5): 677–684. doi:10.1016/0006-2952(82)90449-X. PMID6123322.
^Eil C, Edelson SK (July 1984). "The use of human skin fibroblasts to obtain potency estimates of drug binding to androgen receptors". The Journal of Clinical Endocrinology and Metabolism. 59 (1): 51–55. doi:10.1210/jcem-59-1-51. PMID6725525.
^ abcdefWard OB (11 November 2013). "Fetal drug exposure and sexual differentiation of males.". In Gerall AA, Moltz H, Ward EL (eds.). Sexual Differentiation. Springer Science & Business Media. pp. 207–. ISBN978-1-4899-2453-7. In high concentrations cimetidine acts as a weak antiandrogen by competitively binding to cytosol androgen receptors, as has been demonstrated in rat ventral prostate (Foldesy, Vanderhoof, & Hahn, 1985; Sivelle, Underwood, & Jelly, 1982) and mouse kidney tissue (Funder & Mercer, 1979). In vivo, cimetidine, in high dose levels, causes reductions in prostate and seminal vesicle weights in male rats (Foldesy et al., 1985; Leslie & Walker, 1977; Sivelle et al., 1982). After 6 weeks of daily cimetidine administration to male rats, reduced weights of accessory sexual organs were accompanied by elevated gonadotropin levels (Baba, Paul, Pollow, Janetschek, & Jacobi, 1981). At therapeutic levels in men, cimetidine either has no effect on plasma T levels (Spona et al., 1987; Stubbs et al., 1983) or causes small increases in T (Peden, Boyd, Browning, Saunders, & Wormsley, 1981; Van Thiel, Gavaler, Smith, & Paul, 1979; Wang, Lai, Lam, & Yeung, 1982). The increases in T have been attributed to cimetidine's antagonism of the normal negative feedback that androgens exert on gonadotropin secretion (Peden, Cargill, Browning, Saunders, & Wormsley, 1979). Gynecomastia and even loss of libido that progressed to impotence have occasionally been reported in men taking cimetidine (Peden et al., 1979; Spence & Celestin, 1979), but the occurrence of these disorders is very rare (Gifford, Aeugle, Myerson, & Tannenbaum, 1980). In one survey, gynecomastia, the most frequent endocrine-related complaint, was reported in only 0.2% of over 9,000 patients taking cimetidine (Gifford et al., 1980).
^ abcBarazani Y, Sabanegh Jr ES (26 July 2014). "Risks from Medical and Therapeutic Treatments". In du Plessis SS, Agarwal A, Sabanegh Jr ES (eds.). Male Infertility: A Complete Guide to Lifestyle and Environmental Factors. Springer. pp. 233–. ISBN978-1-4939-1040-3. Like other antiandrogens, [cimetidine] leads to elevated gonadotropin levels by antagonizing the negative feedback control of gonadotropin secretion by testosterone [1, 34]. Cimetidine has been reported to have antiandrogenic effects ranging from gynecomastia to oligospermia [4]. In one clinical study, men administered cimetidine exhibited a significant reduction in sperm concentration compared to placebo-treated controls [35]. In another study of men receiving cimetidine for chronic duodenal ulcers, testosterone and FSH were elevated during treatment with cimetidine compared to both pre- and posttreatment levels. Moreover, these hormonal effects were associated with a reduction in mean sperm count compared to the period after drug withdrawal [34].
^Galbraith RA, Michnovicz JJ (August 1989). "The effects of cimetidine on the oxidative metabolism of estradiol". The New England Journal of Medicine. 321 (5): 269–274. doi:10.1056/NEJM198908033210501. PMID2747769.
^Michnovicz JJ, Galbraith RA (February 1991). "Cimetidine inhibits catechol estrogen metabolism in women". Metabolism. 40 (2): 170–174. doi:10.1016/0026-0495(91)90169-W. PMID1988774.
^Rendic S, Di Carlo FJ (2010). "Human cytochrome P450 enzymes: a status report summarizing their reactions, substrates, inducers, and inhibitors". Drug Metabolism Reviews. 29 (1–2): 413–580. doi:10.3109/03602539709037591. PMID9187528.
^ abcdefghijDeepinder F, Braunstein GD (September 2012). "Drug-induced gynecomastia: an evidence-based review". Expert Opinion on Drug Safety. 11 (5): 779–795. doi:10.1517/14740338.2012.712109. PMID22862307. S2CID22938364. Cimetidine. Spence and Celestin reported a 20% incidence of gynecomastia in a prospective study of 25 male duodenal ulcer patients treated with cimetidine 1.6 g/day [13]. Symptoms developed after 4 months of treatment and regressed within a month of stopping therapy. In another prospective cohort study involving 22 patients, cimetidine caused breast changes and erectile dysfunction in 60% of men which resolved completely in all cases when switched to ranitidine [14]. In the UK general practice database of over 80,000 men, the relative risk (RR) of gynecomastia among cimetidine users was 7.2 (95% confidence interval (CI 4.5 -- 11.3)) as compared with the non-users. Users with a daily dose ‡ 1000 mg had more than 40 times the risk of developing gynecomastia than the non-users. The period of highest risk was 7 -- 12 months after starting cimetidine treatment [15]. Cimetidine blocks the androgen receptors in the breast leading to decreased androgen action causing the growth of breast tissue because of 'unopposed' estrogen action [16]. Another possible mechanism includes decreased 2-hydroxylation of estrogen leading to elevated serum estrogen levels [17]. There also are reports of cimetidine blocking testosterone biosynthesis and causing elevated prolactin levels in individual cases [18].
^ abcDunaway G (1 April 2009). "Androgens and Antiandrogens". In Watts S, Faingold C, Dunaway G, Crespo L (eds.). Brody's Human Pharmacology - E-Book. Elsevier Health Sciences. pp. 472–. ISBN978-0-323-07575-6. The histamine receptor antagonist cimetidine, used to decrease gastric acid secretion in treatment of peptic ulcer disease and esophagitis (see Chapter 14), also acts as an antiandrogen. Thus it has been reported to produce gynecomastia when given in large doses, such as those used in the treatment of patients with Zollinger-Ellison syndrome. Gynecomastia occurs in less than 1% of patients treated with the doses used in peptic ulcer disease. Cimetidine interacts with ARs approximately 0.01% as effectively as testosterone and has been used with limited effectiveness to treat hirsutism in women.
^Copperman AB, Mukherjee T, Kase NG (4 September 2003). "Polycystic Ovarian Syndrome". In Altchek A, Deligdisch L, Kase N (eds.). Diagnosis and Management of Ovarian Disorders. Academic Press. pp. 351–. ISBN978-0-08-049451-7. Cimetidine is a weak androgen receptor antagonist. A controlled clinical study has not found cimetidine to be effective in the treatment of hyperandrogenism.[123, 124] 5.
^ abPregler JP, DeCherney AH (2002). "Approach to the Patient with Hirsutism". Women's Health: Principles and Clinical Practice. PMPH-USA. pp. 595–. ISBN978-1-55009-170-0. Cimetidine is a histamine type 2 blocker, which also binds to the androgen receptor to inhibit its function." However, this antiandrogen activity of cimetidine is weak, and the clinical benefit of its use in women with hirsutism is minimal. Thus, this drug is not recommended for the treatment of hyperandrogenism.
^ abKatsambas AD, Dessinioti C (2010). "Hormonal therapy for acne: why not as first line therapy? facts and controversies". Clinics in Dermatology. 28 (1): 17–23. doi:10.1016/j.clindermatol.2009.03.006. PMID20082945.
^Scheinfeld N (March 2003). "Cimetidine: a review of the recent developments and reports in cutaneous medicine". Dermatology Online Journal. 9 (2): 4. doi:10.5070/D33S15Q645. PMID12639457.
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^Fit KE, Williams PC (July 2007). "Use of histamine2-antagonists for the treatment of verruca vulgaris". The Annals of Pharmacotherapy. 41 (7): 1222–1226. doi:10.1345/aph.1H616. PMID17535844. S2CID19769702.
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