Lots of drugs affect fertility, and some of them are essential for fertility treatments, but many of them significantly reduce the chances of conception.
When we say “drugs”, we’re including hormones and all prescription and non-prescription medications, some of which can cause permanent damage to sex organs and sterility. Most of the research on drugs and fertility has been with sperm, simply because sperm are much easier to work with than eggs:
- Sperm are much easier to access
- There are lots of them
- They’re constantly being made
- Changes in sperm numbers and function can be seen in relatively short time frames
- Sperm tests don’t reduce a man’s fertility, but taking eggs from ovaries does, so there are ethical issues
Sex and Drugs
The sex bias complicates the issue a bit, but eggs and sperm have similarities because:
- They’re both delicate cells undergoing rapid development
- Their DNA is particularly vulnerable
- They’re less able to repair DNA damage than normal cells
- However, sperm are much smaller, and there are many more of them
Some drugs interfere with how sperm develop and reduce healthy sperm numbers, while others affect sex drive and a man’s ability to maintain an erection. As men and women share the same sex hormones, it’s very likely these drugs also affect follicle development, but the lack of research on drugs and female fertility makes it unproven. However, we do have information on how some drugs affect breastfeeding mothers and their babies and therapeutic alternatives.
Non-prescription drugs and fertility
Many 18-50-year-old men take illegal drugs that affect conception rates, and an estimate of illicit drug use by men in the U.S.A is: i
| Age of men | Used a drug in the last year | Used a drug in the past month |
|---|---|---|
| 26-34 | 24.6% | 14.3% |
| 35-49 | 14.5% | 8.7% |
| 50+ | 7.8% | 5.0% |
Clinical trials on illegal drugs aren’t straightforward (due to the ethics involved), but we do know:
| Drug | Impact on men | Impact on women |
|---|---|---|
| Marijuana | Affects the testes and sperm development, causing lower hormone levels (LH and testosterone). Sperm have lower functionality, morphology and motility. ii | Disrupts the menstrual cycles and reduces the development of follicles. It lowers embryo implantation rates and development. iii |
| Opiates (including prescription) | Reduce testosterone production, libido and erectile function. | |
| Cocaine | Impairs erectile function and may reduce sperm concentration. | The children of women who take cocaine during pregnancy are more likely to develop abnormally. |
| Amphetamines | Reduces libido. | |
| Anabolic steroids | Creates abnormal sperm, no sperm, atrophy of the testes and hypogonadism. It can take a year or more to recover fertility. |
Prescription Drugs and Fertility
There’s more research on the impact of prescription drugs on men than women, with the known effects of many medications shown below: iv
| Medication | Effect of reproduction | Length of effect |
|---|---|---|
| Antibiotics: Ampicillin, cephalothin, cotrimoxazole, gentamycin, neomycin, nitrofurantoin, Penicillin G, spiramycin | Impairs the development of sperm | Reversible |
| Anti-Epileptics: Phenytoin
Carbamazepine, oxcarbazepine and valproate Valproate v |
Impairs sperm motility
Many abnormal sperm in samples Smaller testes and fewer sperm |
Reversible
Not known Not known |
| Antihypertensives: Alpha agonists (clonidine), alpha blockers (prazocin), beta blockers,hydralazine, methyldopa, thiazide diuretics
Calcium channel blockers (nifedipine) |
Erectile dysfunction
Fertilization failure |
|
| Anti-inflammatories: Mesalazine, sulfasalazine | Impairs the development of sperm and sperm motility | Reversible |
| Antimalarials: Quinine and its derivatives | Impairs sperm motility | Reversible |
| Antidepressants/ Antipsychotics: Alpha-blockers, phenothiazine (particularly SSRIs)
Butyrophenones |
Increases prolactin concentrations, causes sexual dysfunction (inability to ejaculate or maintain erections) and reduces sperm motility v
Increases rates of sperm DNA Fragmentation vi Impairs the development of sperm and sperm motility |
Reversible for some men; for others, the problems persist |
| Corticosteroids: | Reduces sperm concentration and motility | Reversible |
| Non-steroidal anti-inflammatory drugs (NSAIDS): Cox-2 inhibitors | Impairs the rupturing of the follicle and ovulation and impairs tubal function | Reversible |
Taking medicines is essential for many people’s health; anyone thinking of stopping their prescribed medicines should see their MD/GP as unsupervised withdrawal could have serious health consequences.
Ten “over the counter” drugs to avoid in pregnancy vi
| Drug | Found in | Consumer Reports’ recommendation | Possible alternative |
|---|---|---|---|
| Aspirinvii | BayerExcedrin Migraine | Not recommended | Tylenol(acetaminophen) |
| Bismuth subsalicylate | Kaopectate Pepto Bismol | Use with caution before 20 weeks
Not recommended after 20 weeks |
Imodium(loperamide)
(but this also has side effects) |
| Bromphen-iramine | Dimetapp Cold and Allergy | Use with caution before 36 weeks Not recommended after 36 weeks (9th month) |
Claritin (loratadine);Zyrtec (cetirizine) |
| Caffeine | Anacin Regular Strength, Excedrin
Extra Strength, Excedrin Migraine |
Use with caution, and to reduce the risk of miscarriage, don’t exceed 200 milligrams daily. | None |
| Castor Oil | — | Don’t take: an unacceptable risk | Increase physical activity, drink more fluids and eat fibre-rich foods. Consider psyllium- supplements |
| Chlorpheniramine | Chlor-Trimeton combination products:
Advil Allergy Congestion Relief Alka-Seltzer Plus Cold Formula, Dristan Cold |
Use with caution before 36 weeks
Not recommended after 36 weeks (8th month) |
Claritin (loratadine);Zyrtec (cetirizine) |
| Ibuprofen | Advil, Motrin | Use with caution in weeks 14 to 26 (2nd trimester)
Not recommended before 14 weeks and after 27 weeks (1st and 3rd trimester) |
Tylenol(acetaminophen) |
| Naproxen | Aleve | Use with caution in weeks 14 to 26 (2nd trimester)
Not recommended before 14 weeks and after 27 weeks (1st and 3rd trimester) |
Tylenol(acetaminophen) |
| Nicotine | Cigarettes and all other forms of tobacco;Nicorette gum, Nicoderm CQ patches | Not recommended; however, the benefits of gum or patches to help stop smoking may exceed the risks of smoking during pregnancy. | None |
| Phenylephrine and
Pseudo-ephedrine |
Pseudo-ephedrine products: Advil Cold & Sinus, Claritin-D, Sudafed 12 Hour
Phenylephrine products: Alka-Seltzer Plus Day, Sudafed PE Pressure + Pain, Tylenol Cold Multi-symptom, Vicks Dayquil Cold and Flu Relief |
Not recommended before 14 weeks (1st trimester)
Use with caution after 14 weeks (2nd and 3rd trimester) |
Drink plenty of fluids, consider using steam to relieve congestion and avoid irritants like tobacco smoke |
Note: This isn’t a list of every drug to avoid during pregnancy. Always talk to your healthcare provider before taking medicines or supplements.
For scientific literature and fully referenced information on drugs and other chemicals known to affect breastfeeding mothers and their babies (with suggestions for therapeutic alternatives), please refer to the LactMed® database.
Photo by Myriam Zilles on Unsplash
i The National Survey of Drug Use and Health (NSDUH) conducted by the Department of Health and Human Services (Substance Abuse and Mental Health Services Administration [SAMHSA], 2010)
ii ‘The Insults of Illicit Drug Use on Male Fertility’ Carolyn M. Fronczak, et al. Journal of AndrologyVolume 33, Issue 4, pages 515–528, July-August 2012
iii ‘The manifold actions of endocannabinoids on female and male reproductive events.’ Bari M, et al. (PMID:21196184)
iv’ Lifestyle factors and reproductive health: taking control of your fertility’ Sharma et al. Reproductive Biology and Endocrinology 2013, 11:66
ii ’Effect of epilepsy and antiepileptic drugs on male reproductive health’ J. I.T. Isojärvi et al. Neurology January 27, 2004 vol. 62 no. 2 247-253 doi: 0.1212/01.WNL.0000098936.46730.64
vi Antidepressants may harm male fertility
v ‘Semen Parameters are Unrelated to BMI But Vary With SSRI Use and Prior Urological Surgery’Rachna Relwani, et al. Reproductive Sciences April 2011 vol. 18 no. 4 391-397
vi Information from Briggs GG, Freeman RK, Yaffe SJ eds. Drugs in pregnancy and lactation: a reference guide to fetal and neonatal risk. 9th ed. Wolters.
vii Low-dose aspirin (40 to 150 mg daily) may be prescribed for certain conditions associated with pregnancy such as gestational high blood pressure and pre-eclampsia.
